The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
Big Bang theoreticians have made the claim that 80% or so of gravitating matter in the universe must be some unknown kind of non-byronic matter that is as yet undetected and barely interacts with normal matter (or itself). This claim is apparently needed for agreement with Big Bang nuclear synthesis calculations.
I am looking for any firm confirmation that dark matter cannot be large quantities of cold dark H2, the most common molecule in the universe. I understand that at least someone believes that the FUSE satellite data has proved that no large amounts of H2 exist to account for the gravitating mass. However I have been unable so far to deduce such a claim from science reports from the FUSE project that I have seen.
Can anyone enlighten me on this subject?
Moreover in 1999 large amounts of neutral H2 were detected in the edge-on galaxy NGC 891. The reports suggested that enough was found to account for the missing dark matter. Does anyone know if this claim was refuted?
Finally around 1998 through about 2002 several articles appeared discussing Extreme Scattering Events which have been attributed to a large population of extraordinarily small and dense H2 clouds in our galaxy. Has any further progress been made in this research since? Will the Planck mission data be able to shed some light on the existence of such gas clouds?
Hydrogen and all other atoms and molecules have characteristic absorption and emission spectra including in the < 10 Kelvin blackbody emission region which would be evident if there were massive unmapped clouds of cold dust or gas. There are no such clouds because dark matter is primordial, intermediate mass black holes.[1] We know this because any massive but non-baryonic or weakly-interacting matter would have fallen into black holes billions of years ago.[2] Professor Paul Frampton has been saying this for decades,[3](free at [4]) but the hundreds of astrophysicists who search for WIMPs and axions refuse to listen, because even though there has never been a shred of empirical evidence for such exotic particles (they are merely the hypothetical postulations of supersymmetry, which is not doing so well at the Large Hadron Collider at the moment) there was until very recently no way that anyone had thought of to detect intermediate mass black holes[5][6] so you couldn't get a grant to look for them. Science meets economics and economics wins, sadly. Our Dark matter article is pathetically equivocal on this topic because it's been heavily edited by astrophysicists in favor of their own continued funding, and you can't blame them, really. However, this is not to say that there aren't large unmapped clouds of interstellar hydrogen emitting in the < 10 Kelvin blackbody range; there most certainly are, and they are being detected all the time by, e.g., the Spitzer telescope, but they are orders of magnitude less massive than dark matter. Do you have links for the NGC 891 and scattering observations? 69.171.160.45 (talk) 06:49, 3 October 2011 (UTC)[reply]
I've always thought that "dark matter" (and "dark enery") is simply the "here be dragons" of modern astrophysics. Just a convenient label for "everything we can't specifically identify (yet)", thus it could basically be anything (that isn't "glowing" and thus broadcasting it's identity). Roger (talk) 07:52, 3 October 2011 (UTC)[reply]
An event rate modulation which has been unconfirmed since 1986, and 69 detection events from unexplained sources which are therefore theorized as WIMPs? I'm glad you're not picking my investment portfolio. On the other hand, two intermediate mass black holes have been confirmed for years now. Is there anyone supporting WIMPs who isn't in the community depending on grants for looking for them? NASA doesn't. 69.171.160.119 (talk) 20:37, 3 October 2011 (UTC)[reply]
Another shower of PoV from 69.171.160.119. The 69 events have no other known explanation while the Black holes might not be primordial. Dauto (talk) 22:46, 3 October 2011 (UTC)[reply]
Oh, By the way, the DAMA/LIBRA experiment has collected data as recently as 2009 published in 2010 showing modulation beyond 8.9 sigma confidence limit. Dauto (talk) 23:10, 3 October 2011 (UTC)[reply]
Is there a link for that? I seem to remember that wide binary star measurements are consistent with black holes but not WIMPs. Does anyone remember where that was discussed? 67.21.131.22 (talk) 23:53, 3 October 2011 (UTC)[reply]
The wide binary orbits were once said to be inconsistent with black holes but that has been overturned by [7](free at [8]) but this is not strictly evidence for black holes at present. 69.171.160.201 (talk) 19:48, 4 October 2011 (UTC)[reply]
Any idea if it's made it through peer review? Or how they deal with DM particle accretion in ordinary stellar mass or supermassive black holes? 69.171.160.201 (talk) 19:48, 4 October 2011 (UTC)[reply]
The peer reviewed reference is Eur. Phys. J. C (2010) 67: 39-49. Any claims to constraints coming from possible Black holes are not their concern since it is not related to their experiment. Dauto (talk) 20:06, 4 October 2011 (UTC)[reply]
That just your opinion, not a fact. The observed modulation is quite solid, the explanation given in the paper is reasonable, and I haven't seen any alternate explanation being proposed. Dauto (talk) 20:31, 4 October 2011 (UTC)[reply]
One more thing. The NASA page linked above is talking about micro black holes not intermediate black holes. Micro black holes are just another variety of WIMPs. Dauto (talk) 14:26, 4 October 2011 (UTC)[reply]
Yes, they are. In fact their interactions is even weaker. They only interact through gravity. You need a large mas in order for gravity to become strong and those micro holes have sub-grams masses. Dauto (talk) 20:06, 4 October 2011 (UTC)[reply]
Thanks for everyone's response. I was actually asking more specifically about the search for molecular hydrogen and how much has been found. Here is a link to the 1999 paper about H2 in NCG 891
Here is a link to one of the papers about Extreme Scattering Events probably due to dense H2 clouds: arXiv:astro-ph/9802111v2.
It would appear that very cold clouds of nearly pure H2 would be difficult to detect, so perhaps it still is an unknown, but I'm not sure. Maybe not as exciting as primordial black holes and WIMPs but seems to me scientist should be looking for horses as well as zebras.
The remark about POV is valid but it seems to be the case in this field that not enough is yet known to have a solid scientific theory that can be agreed upon and solidly supported by evidence. After all we don't even know what 95% of the Universe is made of. Carl Hitchon (talk) 00:11, 4 October 2011 (UTC)[reply]
Again, hydrogen or any other gas or dust would emit blackbody radiation, and while that would not be detectable from the surface of the Earth because of atmospheric absorption and heat interference, the several cryostatic infrared space telescopes which have been operational since 1999 have not found any evidence of the necessary masses of interstellar media to explain more than a tiny fraction of dark matter. 69.171.160.201 (talk) 20:06, 4 October 2011 (UTC)[reply]
Actually, this is only true if you assume that the ISM (or H2 gas as DM for that purpose) is actually dense enough to form a Maxwell-Boltzmannn style velocity distribution, which -while only being indirectly related to a Plack Black Body- is required to show this kind of radiation. However, the ISM is mostly regarded as being "too transparent" or in other words, not dense enough to have photon creation by collision on a global scale. This is also the reason why we can observe the rather "bright" 21cm hyperfine structure transition line of Neutral Hydrogen, which would otherwise drown in the pure thermal radiation of HI, considering it being created by a highly forbidden, low probability event.
Can you site a reference indicating that it would radiate as a black body? I thought awestonomers always looked for specific emission and absorption lines to detect the stuff. I've heard the claim that's it's been ruled out, however there do seem to some instances of detection (mentioned above) that could be large amounts. Carl Hitchon (talk) 18:02, 5 October 2011 (UTC)[reply]
A recent proposal is that much hydrogen may be hidden from view in the form of Hydrogen ion clusters, although these too would have an absorption spectrum. Solid hydrogen snow is possible if the vapour pressure is lower than the gas density. However there is a problem with primordial nucleosynthesis if the density of baryonic matter is too great, it does not end up producing elements in the ratio that we see now. Graeme Bartlett (talk) 10:02, 4 October 2011 (UTC)[reply]
The Extreme Scattering Events I referred to are thought to be caused by relatively small (<1AU) H2 gas clouds that are quite dense (10^3 or so times the usual ISM). Yes, I'm well aware of the conflict with the BBN theory and that's apparently why we are looking for harder for zebras than horses (so to speak). Thanks for the references. Carl Hitchon (talk) 18:02, 5 October 2011 (UTC)[reply]
Are there physical or biological lower limits on the size of mammals? In particular, would it be possible for a cat or dog to evolve to an insect-like or microscopic size (full grown), while retaining its basic cat/dog body shape and characteristics? 69.111.16.7 (talk) 03:48, 3 October 2011 (UTC)[reply]
Most mammals (and most birds) are endothermichomeotherms (traditionally, but inaccurately - "warm-blooded"). The smaller the size, the harder it is to maintain acceptable body temperatures for their metabolisms to occur normally. The smallest homeothermic vertebrates (e.g. shrews and hummingbirds), as a consequence have very high metabolic rates. They have to keep eating all the time and require so much oxygen that their heartbeat rates are astonishing (600 to 1320 bpm for the masked shrew).
The other limit, is of course, morphological. This affects poikilotherms and ectothermic homeotherms ("cold-blooded" animals) as well as endothermic homeotherms. A microscopic dog or cat would not have enough space (or cells even) to possess the organ systems necessary to keep functioning. Unless of course, it devolves drastically and manages to find a way to remain alive even after jettisoning most of its organs. Examples of miniaturization achieved by basically giving up the necessities of having to remain alive include anglerfish males which can only survive by becoming embedded parasites of the much larger females (they are basically nothing more than living testes). The males of the fairyfly Dicopomorpha echmepterygis, the smallest insects, also do not have eyes and have no means to feed themselves as adults - they only live to fertilize the females immediately after emerging as adults, then die. Even down to the mm range, there are already constraints as to what can be fitted into a body. In the smallest vertebrate adults, fish of the genus Paedocypris, the skulls have become cartilaginous and roofless, leaving their brains exposed. In the tiny Thorius salamanders, the eyes and the brain have a larger "smallest operational sizes" than other elements of the skull and thus now take up much of the space.
And lastly, smaller sizes means different niches. They have to adapt to different ways of acquiring food, different methods of locomotion, etc. And that means necessarily changing body shape. So no, a microscopic vertebrate is impossible. -- Obsidi♠nSoul06:53, 3 October 2011 (UTC)[reply]
"Or"? Most currently-used English Bibles are pretty clear about it being seven pairs (or seven and their mates) in Genesis 7:2. Direct translation of the Hebrew agrees ("you shall take seven seven man and woman of him") So WP:V wins again. DMacks (talk) 12:00, 3 October 2011 (UTC)[reply]
Maybe the scribe stuttered? Oh well... at least we got a rainbow out of it. Antediluvian Earth must have been completely monochromatic.-- Obsidi♠nSoul12:25, 3 October 2011 (UTC)[reply]
Are shrews smaller than marmosets, or are these just young? I guess they are young, since Shrew says, "several are very small, notably the Etruscan Shrew (Suncus etruscus) which at about 3.5 cm and 2 grams is the smallest living terrestrial mammal." Terrestrial? Is there a tiny dolphin or something? 69.171.160.45 (talk) 07:56, 3 October 2011 (UTC)[reply]
The larger marmosets in those pictures are (assuming the hand is of an average adult human) at least 10cm long excluding their tails, and by comparison even the smaller younger ones are considerably larger than a typical adult shrew. {The poster formerly known as 87.81.230.195} 90.197.66.215 (talk) 08:33, 3 October 2011 (UTC)[reply]
I think that might actually be an Imperial hand, although in the current context its difference from the Metric hand is not great enough to be significant. {The poster formerly known as 87.81.230.195} 90.197.66.215 (talk) 18:10, 3 October 2011 (UTC)[reply]
I have only found this message a day later! How you find who edited an article is by looking at the history. A talk link will be listed against the editor. Graeme Bartlett (talk) 09:51, 4 October 2011 (UTC)[reply]
Losing weight
In terms of attempting to lose weight ... why do they say that when you have more muscle, it helps you to burn more fat? What exactly is the relationship between the two? What are the basics of the underlying concepts involved? What is the basic physiology or biology involved with that concept? Thanks! (Joseph A. Spadaro (talk) 15:27, 3 October 2011 (UTC))[reply]
Perhaps it's very simple and just means that when you have more muscle you can exercise more strenuously and for longer. And when you exercise you burn calories. Itsmejudith (talk) 16:14, 3 October 2011 (UTC)[reply]
I don't believe that's right Judith. More muscle increases the Basal metabolic rate which makes you burn more energy along the day. The energy that you lose through exercise it not very high (despite popular believe that exercise can make you thin). That's why you always have to combine exercise ((muscle building and aerobic) with a diet to lose weight. Trustinchaos (talk) 16:20, 3 October 2011 (UTC)[reply]
You lose 100-150 kcal for every mile you walk or run. That translates into 20-30 miles per lb of fat. Most people in reasonable condition could walk/run 3-4 miles a day, which is around 500 kcal. Many people might find it easier to just eat 500kcal less, but doing both is how to lose weight the fastest obviously. Googlemeister (talk) 16:25, 3 October 2011 (UTC)[reply]
That implies losing about 3-4 pounds/month, which is not much, but only if you indeed walk 3-4 miles every day, which is more than most people do. Provided that you don't eat more (or more energetic food/drinks), it could work for losing a little bit of weight, but it's highly improbable. Wikiweek (talk) 22:04, 3 October 2011 (UTC)[reply]
Most doctors don't recommend people try to lose more then 1-2 lbs per week in normal circumstances. And if losing weight was easy, there wouldn't be a multi-billion dollar industry for it. Googlemeister (talk) 13:29, 4 October 2011 (UTC)[reply]
That's double of what I said, but you are right, losing weight is not as easy as it sounds, specially not gaining it again can be a tough thing. Wikiweek (talk) 20:59, 4 October 2011 (UTC)[reply]
Just keeping tissue alive (even if you're not moving about or visibly 'exercising') burns a certain number of calories (as noted by others, see basal metabolic rate). This page suggests a burn rate of 7-10 calories per day for every pound of muscle tissue, versus approximately 2-3 calories per day per pound of body fat. So keeping a pound of muscle alive for a year burns about 3000 calories—the amount of energy, coincidentally, stored in a pound of fat.
Of course, you're likely to burn far more calories than that in the activities used to build and maintain that pound of muscle than you ever will relying on its contribution to your basal metabolic rate. (If you start with a pound of muscle and don't use it for a year, it won't still be there at the end of the year, and your body will have used up the material in that muscle (catabolism) as a source of energy.) TenOfAllTrades(talk) 16:53, 3 October 2011 (UTC)[reply]
One reason for that would of course be that no one in the U.S. has been daft enough to eat potato fruits in the last 50 years... =) JIP | Talk18:49, 5 October 2011 (UTC)[reply]
Petroleum value and chemical uses
I was very surprised to read a statement in Nature News, "Eighty-five percent of the volume of a barrel of oil is used to make fuel, but the chemicals that come from the remaining 15% account for 85% of the barrel's monetary value." I'm skeptical... is there truth to this?[9]
For example, if a barrel of oil cost $100, and this is true, then with petroleum at $100, 55*0.85 = 47 gallons of petroleum destined for fuel should cost $15 - the base cost of the fuel, before refining, should be about $0.33.
More to the point, if this claim were true, then if the technologies discussed in the article, such as biotech isoprene for tires, come to fruition, the base cost of the fuel should be increased. This is because the chemical part of the oil becomes less and less valuable due to competition, whereas the expense of producing it doesn't decrease. (If capitalism even applies to the oil market, which I'm also a bit skeptical about). If that 47 gallons has to produce most of the $100 cost of the petroleum, the base price of the fuel rises $1.66 per gallon to around $2.00.
I suspect what they really mean is that, after the chemicals are worked on, adding value, they become more valuable than bulk fuel, not that those fractions of the oil are more valuable to start? Wnt (talk) 19:21, 3 October 2011 (UTC)[reply]
At face value it sounds very fishy to me too. Another possible reading that I could imagine is if "value" were understood as "profit" for refiners. I could easily believe that there isn't much profit margin in gasoline for refiners, and that the profit margins on the less common refined products might be much higher. Dragons flight (talk) 20:00, 3 October 2011 (UTC)[reply]
Some of the longer chain hydrocarbons in petroleum are used to synthesize ridiculously expensive pharmaceuticals, and less expensive pesticides which are still often much more valuable than fuel by weight. 69.171.160.201 (talk) 20:16, 4 October 2011 (UTC)[reply]
Mean swell wavelength in the open ocean
What is the mean wavelength of swells in the open ocean? E.g. if I placed a large number buoys in the open ocean at random and collected wave data for several years, then looked at just the wavelengths, and averaged them, what length would I get? Standard deviation would be great too! :) — Preceding unsigned comment added by 131.107.0.115 (talk) 20:25, 3 October 2011 (UTC)[reply]
The wavelength depends on the speed of the waves and the speed becomes roughly equal to the speed of the wind.[10]Wind wave says
using the notation in the article. For deep water
so λ is approximately (0.8c)2 where λ is in metres and c in m/s. Swell tends to continue in this way even after the wind has stopped (all this in Wind wave). I expect you were hoping the weather wouldn't come into things! Thincat (talk) 23:11, 3 October 2011 (UTC)[reply]
Thanks for this. I understand that wavelength is a function of wave period and speed; I guess what I'm really asking is what is the actual value? — Preceding unsigned comment added by 131.107.0.95 (talk) 00:01, 4 October 2011 (UTC)[reply]
There is no actual value for the average wave length. Waves come in ripples and tsunamis, so the mean you'd want is completely dependent on the accuracy of the buoys used. An extremely precise buoy might come up with millimeters. A very nice read about waves (how they work, how they're measured, and a lot more) is in Oceanography and Seamanship by William G. Van Dorn. Joepnl (talk) 01:04, 4 October 2011 (UTC)[reply]
Thanks Joepnl, I hadn't considered that a buoy could register a 1 mm change in water height as a wave (which I suppose it is; it sounds like now we're getting in to defining what a wave is) or that a buoy would be unable to differentiate the peak of one wave from that over another passing at a different speed. — Preceding unsigned comment added by 131.107.0.94 (talk) 01:13, 4 October 2011 (UTC)[reply]
The buoys can differentiate between different waves coming from different directions at different speeds. One cool thing I learned from the book I mentioned is that Fourier transformations are used to calculate where all the waves came from. Joepnl (talk) 01:29, 4 October 2011 (UTC)[reply]
Awesome! I'm disappointed that I'm not getting a quick answer to what I thought was a simple problem, but I am beyond stoked to find out that something I thought was simple (because I wasn't really thinking about it) opens the door to what looks like a super interesting subject. I can't wait to dig into this book.
Waves are just a small part of it but it seems that every (non-scientific) article about waves refers to this quite old (and pretty expensive) book which is about seamanship, really. Waves are really interesting. I thought an object on a wave was just going up and down. But the water needs to go somewhere. So here are some more fun facts: a floating object on a wave moves in circles, the circles go on below the surface, and they go on way further down than you'd expect. I think that smart kids learning about where canon balls should land after being shot at X degrees at speed Y should also be learning how waves work. Btw, thank you for making me look up the word "stoked", I'm learning here as well :) Joepnl (talk) 00:33, 5 October 2011 (UTC)[reply]
My cat pees on a power socket. Why? How can I stop it?
He's done it three times now! After each incident I've removed the power socket (known as a power point where I am in Australia) and left the wires there (with the live ends suitably covered with insulating tape) while I unstressed myself, cleaned everything up, and figured out how to stop it happening again.
Most recently, some badly stained carpet was completely removed, and the timber flooring and wall panelling thoroughly washed and sealed with two layers of a quality timber finish. The cat stopped showing any interest in the area. The power socket was finally replaced two days ago after a couple of months. First, the cat peed on the floor close by, then peed on the power socket itself, shorting out the power for the house, again!
Why? Any cat psychologists in the house?
How do I stop it? Sensible repellent suggestions welcome, but please don't recommend citronella. That repels me as well. HiLo48 (talk) 20:47, 3 October 2011 (UTC)[reply]
There are passive infrared sensor devices that emit ultrasonic sound and spray gasses or liquids or whatever concoction you enjoy. Some cats are deterred by whatever puts them on alert to possible danger. Even a wind blown CD outdoors will keep them searching for the places they feel safe. --DeeperQA (talk) 23:49, 3 October 2011 (UTC)[reply]
The approach is twofold: make the area he's peeing in less attractive, and make the area you want him to pee in (presumably the litter box) more attractive. So, you want to make sure that he likes the litter you're using (no scent might be better than scented), that you change it often, that the box is in a quiet, safe, and convenient place. He may prefer one with a "privacy" lid, or may prefer an open-topped type. To make the socket area less appealing, you want to be sure that previous urine mistakes are thoroughly cleaned up (may need enzyme-type products to do so). Purportedly, some cats don't like walking on aluminum foil, so spreading it out on the floor might also make the area less appealing. - Nunh-huh00:24, 4 October 2011 (UTC)[reply]
Perhaps put his bedding, such as a nest bed, there or nearby, because if he is still a healthy cat he should be keeping his den area clean and not marking it... or perhaps a small bowl of dry food down on a mat in the area for him to graze, because you wouldn't think he would want to ruin his appetite. I can't say for sure if those ideas would work though, and, in any case, since this is also a question of safety; yours, your home and the cats from both electric shock and fire due to the high current from an electrical short, you should block his access to the outlet. Thus, I'd put some plastic and a throw rug over the area to protect the floor and a bookcase or chest against the wall so that there is absolutely no chance of a repeat episode. --Modocc (talk) 04:54, 4 October 2011 (UTC)[reply]
Thanks guys. There's some creative ideas there. The food bowl idea could work. I'm aware of the safety issues. We do have what's called a safety switch here in Australia which automatically and very quickly turns off the current when it detects high leakage. I still think the dumb cat is rapidly working through his nine lives though. I'll put the idea of something blocking access into my subconscious to see if it can come up with something appropriate for the location. HiLo48 (talk) 05:37, 4 October 2011 (UTC)[reply]
Here in the UK we have Feliway pheromone diffusers, which you plug into the socket and which emits a "happy cat" odour. I wonder if putting one of these in the socket would confuse the cat enough to send him away happy? --TammyMoet (talk) 07:32, 4 October 2011 (UTC)[reply]
Wow, that looks highly relevant. The vet has said before that this cat is very susceptible to stress. (There is actually very little stress in its life. It's just crazy.) And your web link even took me to the company's local counterpart in Australia. Thanks. HiLo48 (talk) 21:44, 4 October 2011 (UTC)[reply]
It seems very difficult to apply a subjective ethical determination like "evil" to a power meter with any real meaning or significance. Issues of data protection certainly exist, but I'm not sure what you're wanting beyond that. — Lomn22:18, 3 October 2011 (UTC)[reply]
They're certainly not popular. Your question is very topical in my neighbourhood. Our local major spreadsheet newspaper (not the more popular Murdoch tabloid) has just published this article with the headline "Smart meters given a fail". HiLo48 (talk) 22:19, 3 October 2011 (UTC)[reply]
It depends what you use your electricity for. High electricity use seems to be a common way that hydroponic marijuana growing is detected around my part of the world. (Not suggesting that our OP is an indoor gardener.) HiLo48 (talk) 22:27, 3 October 2011 (UTC)[reply]
Yes, they could know when I am at home/at the office, and therefore call me offering some junk product or service. And a hacker could break into the system and know exactly when I am at home and more or less what I am doing - they could discover how many appliances I have. A potential employer could discover that I rarely stand up early, but come home late at night many days during the week. The question is not how they could use my private data, the question is that they are my private data. Wikiweek (talk) 22:41, 3 October 2011 (UTC)[reply]
Given the meters are individually hackable and regulatable, yes, their mandatory installation is yet another statist evil.μηδείς (talk) 22:31, 3 October 2011 (UTC)[reply]
Not for the first time, you win this weeks most stupid answer competition. Congratulations. That there are risks associated with access to banking facilities from the internet has no bearing whatsoever on the question of whether or not smart meters are evil. So. Did you have a point to make or were you just a bit pissed off that your previous stupid comment had been proven to be, err, stupid? --Tagishsimon(talk)00:00, 5 October 2011 (UTC)[reply]
In NZ there is no regulation or legal requirement for power companies to install smart meters. (Most major power companies here are state owned enterprises which in NZ means they operate more or less as private companies albeit with the government as share holder.) Howevering probably figuring it will be cheaper in the long run, they're doing it anyway but not bothering to make sure their meters have support a home area network to provide any info to the consumer or are compatible with each other [11][12][13][14][15]. If you want those you'll usually have to install a device yourself whicn connects to the power line since there doesn't seem to be any easy way to get it from the smart meters. Without your seperate power meter you paid for directly, any info on usage needs to come from the power company (if they want to provide it) and at best tends have a day granularity [16][17]. Some installers have even admitted said there is basically no real benefit to the consumer for the smart meters that are being installed, it's all to the power company. Of course if you don't want an ordinary smart meter, a prepaid one is an easy option, just don't pay your bill on time once [18]Nil Einne (talk) 23:57, 3 October 2011 (UTC)[reply]
(edit conflict)As an anthropologist I can say that the idea of evil varies greatly from culture to culture and doesn't really have a concrete definition; it's also a matter of opinion. If you define evil from a US perspective though, evil would mean Communist. As I don't like electric metres given that they are depressing (that's money they're measuring); then I, as an American, must define it as most likely Communist and therefore evil. Question answered. As for a serious answer, it's hard from them to really pin down the make and model of appliances you are using. Even if a hacker did care enough to look at your smart meter thingy, it wouldn't tell him the type of computer you use, the OS, programs, passwords, or any other thing of remote interest to him (or her). I don't think that your employer would access your meter without your permission either.... Sir William Matthew Flinders Petrie | Say Shalom! 6 Tishrei 5772 00:06, 4 October 2011 (UTC)[reply]
Technically a potential employer could demand to see your meter info before they offer you a job, or make it a part of your contract you need to give them access when employed. You could reject such a condition, but if you're fairly low-skilled with a lot of people competing for the same job you may have limited choice if you want to make a living. Now, why they would want to do this, I'm not sure, unless you live alone the fact there's high power usage late in to the night won't necessarily tell them you sleep late, nor will a sudden drop at say 9pm tell them you sleep early (perhaps someone else does and you don't bother with lights when using your computer). Also in evil statist countries, it may be illegal for employers to make such demands and even if it isn't it may become so if they start doing it. Nil Einne (talk) 13:27, 5 October 2011 (UTC)[reply]
It's worth considering whether one's electricity usage counts as private information that ought to be concealed. I'm not sure it does. Does one really generally expect that such information is kept confidentially? The meters usually are accessible from the street, their numbers displayed. The power company gives you no assurance that your usage is considered private information. The possibility of misuse seems ridiculously low, even with the idea that "hackers" are somehow getting all of the data at once. The potential threats to any individual seem nil — your named threats are that you are afraid of some so far totally ridiculous schemes by which telemarketers or employers, none of which sound very plausible to me, and all of such ills could be cured through separate policy (if employer actually did start discriminating on the basis of electrical meters, the easier option is to just ban that sort of discrimination). Anyway it all seems rather silly to me. I don't see any "evil". I'm not sure I see anything that actually even ought to legitimately harm or irritate the consumer, other than the apparent fact that they may not work correctly or may be expensive. (Which I consider a separate question from the privacy issue. Smart meters may not be a good idea, but I don't see how privacy has anything to do with that. There are far bigger fish to fry in the privacy arena.) --Mr.98 (talk) 01:02, 4 October 2011 (UTC)[reply]
I'm not sure it does not count as private information. BTW, it doesn't matter if people expect that it will be kept confidential and it doesn't matter if you expect it to be misused or not. If it's your private information no company should be using it for purposes other than agreed upon. And it doesn't matter if I cannot imagine any real harm that could be done. Wikiweek (talk) 13:13, 4 October 2011 (UTC)[reply]
You keep stating that you think it is private information, yet you offer up no criteria for deciding what you should be private and what should not. My analysis is based in the concept of privacy in US law; what are you offering up as yours? --Mr.98 (talk) 23:14, 4 October 2011 (UTC)[reply]
Information on the energy leaving their network and entering your house would seem to be as much their information as it is yours. Of course, you always have the freedom not to buy electricity from the power company. Dragons flight (talk) 23:56, 4 October 2011 (UTC)[reply]
To answer questions above, note that tools are not evil but foolishly installing tools open to abuse by hackers and the police state is a bad thing and when mandated by the government (you know, the ones who put you in jail, seize your property, and shoot you if you resist) it is evil. And Mr. Petrie, what it the world are you talking about saying evil in the US is defined as Communism? Evil is simply willful harm of any sort. Malice or (reckless disregard) which violates another. That's not a difficult definition. Doesn't require, but does include Marxist dictatorships. μηδείς (talk) 01:17, 4 October 2011 (UTC)[reply]
Ah, that is a joke I use sometimes, making fun of my country's tendency to refer to certain things as Socialist or Communist (though I am a socialist myself and have no real dislike of the communist idea itself, just the results of its practice thus far). Willful harm as defined by our values, but in anthropology, you learn to grey the hell out of everything you consider as many things we view are viewed very differently in other cultures. And I'm afraid that Prof. Petrie is no longer with us. Sir William Matthew Flinders Petrie | Say Shalom! 6 Tishrei 5772 01:27, 4 October 2011 (UTC)[reply]
The problem here seems to be that once a "technical upgrade" is envisioned, there seems to be no discretion in deciding what features to add. You could make a smart meter that tots up the electrical usage during each hour of the day and can be interrogated for a monthly report for billing purposes, to encourage conservation - yet not give it the ability to shut down the home's access to current, nor give it any real-time monitoring ability so that someone can try to figure out exactly what kind of grow light is being used in the house, nor allow it to spy on RF signals leaking down the line from a computer monitor nor receive sound recordings from bugs concealed in the house. (I'm not sure they do every last one of those things, though nowadays, one expects it until proven otherwise - and is usually right) Wnt (talk) 03:29, 4 October 2011 (UTC)[reply]
Puh-leeze. These thing are not that smart. And the fallout from violating various wiretapping laws (yes, there are laws about this sort of thing!) would be huge and prohibitive. These things almost surely just measure the electrical output and send it home when they ask for it. If there's no reason to suspect otherwise, it's ridiculous to assume they have all sorts of nefarious capabilities that are well outside their technical specifications. --Mr.98 (talk) 23:14, 4 October 2011 (UTC)[reply]
Not that I agree with Wnt but I disagree with your idea the only thing they can do is to measure the output. Some do in fact have the ability to do remote disconnects (meaning the power company can send a signal to your meter to cut off your power completely) and some do have a home area network meaning they could cut the power to certain devices when receiving a signal from the power company, but only if the device supports it. This is mention in our article on smart meters. However these features aren't hidden, in fact the HAN feature is generally an advertised one (remote disconnects perhaps less so but I see no sign it's usually hidden). The rest of the stuff is largely nonsense. (Well the real time monitoring of power usage is obviously real, any ability to figure out what devices you are using and when would depend entirely on their remote computer systems. I do agree they're unlikely to be able to figure out that much.) Of course, cutting off the power to certain devices isn't new, we've had it in NZ for hot water heaters for years and see Load management. Nil Einne (talk) 13:18, 5 October 2011 (UTC)[reply]
If you are going to insist it is private, you should give some argument as to why. So far the argument has been based on the potential of misuse. This would be a valid reason, if the potential was really there. I'm not sure it is, more than a lot of other information that is not considered private. I still don't understand what hackers are supposed to be doing with this information, or what the police state is supposed to be doing with it, or whatever. This seems like a lot of to-do about nothing. I wonder if you put as much thought into your choice of ISP or phone carriers, who almost surely are doing things that you would definite as violations of privacy or police state-ish. --Mr.98 (talk) 23:14, 4 October 2011 (UTC)[reply]
A smart meter could tell the police right away if I am at home. A normal meter gets read only once in a while, and only if I allow it. You seem to believe that it doesn't matter, since the police just persecute criminals. However, keep in mind that some people around the globe want (yes, that's true) to have a weak police force, which cannot control the whole of the population. It's certainly not a sensitive private data issue (like race, health, sexual preferences), but I still believe citizens have a right not to be the object of surveillance. Regarding the ISP or phone company, the problem is even more acute. Wikiweek (talk) 12:14, 5 October 2011 (UTC)[reply]
Personal information in general is information that can be tied to you. So, 1,80 m is not personal, but Wikiweek: 1,80 m is. But, not all personal information is worth protecting. Applied to the case of energy consumption, 50kw/h for client number x is not private, but 50kw/h for wikiweek is. There are ways of anonymizing information and still being able to process it to provide a service, which is perfectly legit.
A second point: just knowing how much energy you are consuming does not give much clues about what you are doing. Modern devices are as smart as the smart meters: they stop and start autonomously. Refrigerators do that since ages, a computer downloading a file will also change it's consumption of energy without user's input, you cell-phone will stop charging after the battery is full.
Third: the easier way to track you down is through your cell-phone. This would be, if hacked illegally or tapped by the police, one of the best sources of private information from you too, together with your computer. However, most people rarely care about the security of their computer, and even less about the cell-phone. They equally join unknown wifi nets, choose weak passwords and do much more things that are potential insecure. Some evil private data gathered have much better sources to hack than a smart meter. Quest09 (talk) 14:49, 5 October 2011 (UTC)[reply]
And don't forget about NFC. Makes stealing someone's money much easier. "Oh my, he's stolen my e-wallet! Well, I'll just use my cellphone to call the bank and... wait, that was my e-wallet". Even having a BB won't help you with that. Sir William Matthew Flinders Petrie | Say Shalom! 7 Tishrei 5772 19:12, 5 October 2011 (UTC)[reply]
In response to Mr98's question above, police have been using electrical profiles of houses to look for grow lights (i.e. for marijuana) for decades - I think they were doing it even in the 70s in some crude way.
But beyond this, there's a separate risk that emerges when collective data becomes too available, that goes beyond the risk to one individual. If the electric company knows when one person turns on his air conditioning, there is little they can do with that. But if they know they know when every single person turns it on, then they might decide to charge a higher rate for turning it on during peak times, for example. Now such programs in real life are generally voluntary and perceived as a discount good for the environment; nonetheless, it would be possible for the information to be used in a way customers wouldn't like. Wnt (talk) 19:40, 5 October 2011 (UTC)[reply]
Well, they are collaborating in an unjust campaign to deny basic civil liberties for the sole and deliberate purpose of enriching and expanding the Zeta and Sinaloa cartels. Wnt (talk) 03:21, 6 October 2011 (UTC)[reply]
You know, peaking power really does cost the power company more to produce than baseload power. For large industrial and commercial users, charging more for power during peak times has actually been pretty standard in many jurisdictions for quite a while. That kind of detailed, time-resolved monitoring had been expensive though so it wasn't economical to apply at a residential level, but the wide distribution of smart meters is changing that. I wouldn't be surprised to see the actual costs of peak power passed on to all consumers in the not-too-distant future. Dragons flight (talk) 20:17, 5 October 2011 (UTC)[reply]
Indeed, charging more or less under market conditions wouldn't be much different than what happens with other services and products. Quest09 (talk) 20:22, 5 October 2011 (UTC)[reply]
Oh, it's all perfectly good logic, and yet, it's a reason why customers might legitimately object to the meters. Maybe they don't want to think about when they're using electricity. There are other industries where intelligence and flexibility create huge disadvantages - for example, consider how preferable it is in a city to use a train rather than a bus for public transit. It's not really that the train is all that much faster - the point is, it's locked to a track and there's no way to move it. You can't have one schedule for weekdays, one for Saturdays, one for Sundays, one for holidays and Labor Day, all with different routes here and there (as is literally the case for the Madison, Wisconsin bus system). Another example would be the supermarket's quaint simplicity of ordinary cash and fixed prices versus the glitzy game of shopper cards, credit cards, "cash back", etc., all played out in daily bottlenecks at the card reader. Stupidity can be liberating ... it has a hidden sensibility to it. Wnt (talk) 03:19, 6 October 2011 (UTC)[reply]
No one is likely to force you to think about when you use electricity. If you don't want to think that's your choice, you'll just potentially have to pay higher prices then if you thought a little about it. Note that long term, depending precisely on how people react and how the companies choose to adjust their rates, those who choose not to think about it could still end up paying less then if that info had not been available. Similarly I don't know where you live but in most countries you can still use cash, no one is forcing you to use anything else. On a personal level, I find credit cards and debit cards much simpler then cash a lot of the time. No need to look for change or anything like that and although this does depend on your financial system and bank set up, often no need to worry about whether you have enough money (without carrying a lot of cash around). Your comment on buses vs trains isn't that accurate either. It depends significantly where you live.Nil Einne (talk) 06:49, 6 October 2011 (UTC)[reply]
I'm not really disagreeing with you much - I'm not actually an activist against smart meters. I just wanted to point out that opposition to them can be rational, and hope that a vigorous discussion about such issues will help to ensure a better outcome. From your "depending precisely..." statement it sounds like you actually agree with me that the meters could be problematic for some people. Wnt (talk) 13:55, 6 October 2011 (UTC)[reply]
No, I'm simply saying if they actually cause people to significantly modify their behaviour, by their own choice, then this could lead to a significant reduction in the peak demand which could lead to a lower price for everyone. On the other hand, if most people, again by their own choice, don't adjust their behaviour then it may not. In such a case, the majority may end up paying a slightly higher price, with some (those who do adjust their behavior) paying less. However it doesn't automatically follow these people will feel hard done by. They may recognise that it was their choice not to adjust their behaviour. Nil Einne (talk) 15:26, 6 October 2011 (UTC)[reply]
I just had a can of Manischewitz Chicken Noodle Soup and I noticed afterward that there's 20g of protein per serving for a total of 40g in all. Here is the nutritional fact label [19] So, why does this wee can of soup have more protein than a bottle of that Super Protein Odwalla stuff? Is it the egg noodles? Sir William Matthew Flinders Petrie | Say Shalom! 6 Tishrei 5772 00:19, 4 October 2011 (UTC)[reply]
Could be from the grain the noodle is made from. Wheat has a lot of protein. Chicken breast also has a lot of protein. Other than that can't think of anything. --DeeperQA (talk) 00:51, 4 October 2011 (UTC)[reply]
So, another question. First the context. After consuming an omelette composed of ten large eggs, I was told by my ima that I need to have egg white omelettes from now on or I'll have a heart attack, etc. I looked at Wiki's article about them and saw that 4/5 of the egg's protein is contained in the egg whites, but it says nothing of the vitamins (unless I missed something). So my question is, what is the usual vitamin content of egg whites in a large egg? I'd like to know before I consider switching to egg white omelettes. Sir William Matthew Flinders Petrie | Say Shalom! 6 Tishrei 5772 00:27, 4 October 2011 (UTC)[reply]
Little vitamins. Many sites on the Internet provide the exact breakdown. (Nutitiondata) I purchased 50 lbs of egg white to support the protein requirements of my diet and depend upon vitamin supplements for vitamins. However I have returned to whole fresh eggs since the egg yoke has many vitamins and I take a Lecithin concentrate (400mg) 3 times a day plus a prescription medication to keep the cholesterol under control. --DeeperQA (talk) 00:43, 4 October 2011 (UTC)[reply]
Ima? You do realize unless your under medical advice to cut out yolks entirely you could cut down to one whole egg and a few eggwhites on top? It'll taste better too. Ten eggs'd kill anybody. There's the case of that guy on death row got a reprieve and died from the final meal of two whole chickens and a five lb bucket of peaches he'd eaten. μηδείς (talk) 00:55, 4 October 2011 (UTC)[reply]
Ima is the rapport of every Israeli child (though usually said as imaaaaaaaaaaaaaaaaaaa!!!!!!) Yeah I was thinking about that. It would be half and half though as I use one of those pans with the weird egg guy on it and it only fits two eggs at a time (and cooks them in a manner similar to pita bread with an air pocket in the center). Last doctor's check I had just had two slices of cheese pizza and so the doctor thought it best to wait on a cholesterol test (though a few years back I had had a cholesterol issue of levels which sounded like they would be fatal from the Wiki article). Come to think of it, the perscription slip for one is lying right there on the end table since 22 August. Meh, if I didn't eat it, my dad wouldn't have he was concerned that it had sort of missed the spatula if you get my meaning (though I roasted any germs off). I probably won't eat one that big again though, but man was it good (with a lot of parsley in it). Well the inmate sounds like an idiot for eating that many peaches, and I have a desire to lol, but at the same time... not a bad way to die, really. Sir William Matthew Flinders Petrie | Say Shalom! 6 Tishrei 5772
Isn't it true though that the cholesterol in your blood is not terribly related to the cholesterol content of the food you eat since the cholesterol in your blood is stuff that you yourself produced from fat? Googlemeister (talk) 13:19, 4 October 2011 (UTC)[reply]
It is quite true afaik my good sir, but try telling that to a Jewish mother. From what I have read, your body will either excrete excess food cholesterol or produce the missing on its own; the bad evil heart clogging cholesterol comes from saturated fats, or, more specifically, the content of delicious Hagen Dasz Ice Cream sundaes and beef ribs. :( Sir William Matthew Flinders Petrie | Say Shalom! 7 Tishrei 5772 01:10, 5 October 2011 (UTC)[reply]
Our nearby Whole Foods was selling ostrich eggs at one point, but I didn't like eggs at the time. Now that I do, they've stopped selling ostrich eggs! How do those taste compared to chicken omelettes (not that my spicing can't fix anything)? Sir William Matthew Flinders Petrie | Say Shalom! 7 Tishrei 5772 01:10, 5 October 2011 (UTC)[reply]
Unless maybe you are in South Africa or something I would think an ostrich egg would have to be way more expensive then the number of chicken eggs it would take to make a similar sized dish. Googlemeister (talk) 13:14, 5 October 2011 (UTC)[reply]
Hi,
every time that someone makes a buzzcut, you can see its scalp.
Well my question is why on the the top of the head you see the skin, and on the other places you can't, another question is which parameter is related to this subject. — Preceding unsigned comment added by 77.126.59.28 (talk) 00:35, 4 October 2011 (UTC)[reply]
It depends on the angle of vision, the type of cut caesar haircut, fade haircut and the fact that hair does not all lie flat, with hair on the top of the scalp of people with straight hair usually curling outward from a hair whorl or cowlick. Ask a friend to let you examine his hair next time he gets such a cut. Run your fingers across the top of his head, then around the ears and up the back of his neck and see how it feels. μηδείς (talk) 01:44, 4 October 2011 (UTC)[reply]
Though I suffer from both acrophobia and a sincere fear of flying, during a flight the one thing that does not bother me is the height we're at. It's great to be able to land and recognize individual trees because it means we're about to have an end to this quest. But this is when we're still at a 1000 feet. Being on a balcony at 200 feet scares me. The 1000 feet in a plane is something I seem to take for granted, the 200 feet is actually quite high and obviously I could easily fall over this rather low fence, strange that nobody else seems to acknowledge in what horrible situation we are, I hate this evil architect who probably never walked here himself and probably lives in a bungalow, etc.
My theory is that the big difference is that in the case of flying there is no building or rock I need to trust not to fall apart. My evolutionary brain obviously doesn't understand that falling from a hot air balloon is just as deadly as falling from a big building because my genes never had to deal with flying to survive. My genes also never had a problem with heights when walking up a 200 ft hill. In my experience, acrophobia does not really imply a fear of height itself but a fear of the consequences of a failing construction which are obviously higher at 100ft than at 10ft. I see no mention of that in Acrophobia and I would like some insight in my own phobias :) Joepnl (talk) 00:40, 4 October 2011 (UTC)[reply]
I don't know from phobias, but I share your seeming dichotomy about flying vs. balconies, except that I don't have any fear of flying at all. I feel "safe" in an airplane because it's totally enclosed. (I could be wrong, but if I'm wrong, I'll only be wrong once.) Being anywhere near a situation where I could either fall off a high place or where a structure such as a balcony railing could give way, has the effect of making sure I keep well away from the edge. And the photo of Phillippe Petit tightrope walking between the World Trade Center towers still gives me sweaty palms. However, keep in mind you could be killed falling from the second story of a building. The only difference in falling a hundred stories is that you have time to think about it on the way down. ←Baseball BugsWhat's up, Doc?carrots→ 06:22, 4 October 2011 (UTC)[reply]
I can't quite understand what you mean by 'my genes...' As I understand it as a sufferer and an ex-therapist who has treated people for other kinds of phobias, the fear is an acquired behavioural problem and has less to do with genes. The anxiety associated with acrophobia can be overcome with help and permanently suppressed. The anxious ideas and emotions felt within an active phobia are always present and always irrational, 'I might throw myself off this parapet', 'If I go any further I will have a heart attack', 'this building could collapse at any moment'. This irrationality is the heart of the beast and once you have been able to overcome the apparent 'truth' of these silly ideas then the phobia will be overcome. Your theory about the plane not collapsing does not hold for many people who fear its mechanical failure/pilot being suicidal/terrorist attack/bird strike etc. etc. Getting a phobia fixed is not difficult, it requires some steely determination as you challenge to destruction those irrational ideas of what might happen. I am not advising you to do anything, that is up to you.Caesar's Daddy (talk) 07:34, 4 October 2011 (UTC)[reply]
By "my genes" I mean that I think that down below there is a rational reason to be afraid of heights. People who are afraid of heights probably live longer than people who really like heights. That's where the genes come in. Being scared too much is acquired as you say. When I was 9 I didn't have it. (But when I was 2, I also didn't have a problem eating poo for which I have acquired a phobia, too). My theory about planes not collapsing is only meant for heights. I experience exactly the things you describe when it comes to flying, but the very odd thing about it is that the height absolutely doesn't bother me. Being "phobia-prone" that's the thing that amazes me. Btw, I do fly when it's necessary, it's just not a nice experience. Tall buildings are easy to avoid. Being afraid of spiders would be more inconvenient. Joepnl (talk) 00:02, 5 October 2011 (UTC)[reply]
I'm curious about this too. It's odd. Tiny planes, large planes, hot air balloons are fine but standing on the edge of cliffs, tall buildings (and I've lived/stayed in many), the decks of large boats, being in tall trees are all scary for me. Being connected to the ground seems to makes a big difference. It's patently irrational because I can rationally compare the consequences (fell off a cliff=wasn't too bad vs botched hot air ballon landing=fractured a rib, hurt like hell) and it hasn't changed my instinctive response at all. Sean.hoyland - talk07:33, 4 October 2011 (UTC)[reply]
Aren't phobias, strictly speaking, irrational fears? I don't know about you but I think that the fear of falling off a 100 ft cliff to be perfectly rational. It would be irrational if one were to fear a cliff which was only 4 feet tall. Googlemeister (talk) 13:14, 4 October 2011 (UTC)[reply]
Yes, I guess a phobia is by definition irrational but it's odd how some responses are pretty resistant to evidence and experience e.g. people only have to put their hand in a fire once to not do it again and they aren't left with an irrational response everytime they see a fire whereas most phobias are hard to dislodge. I guess it would be rational to fear heights etc if it made someone more careful in those situations but oddly it often seems to have the opposite effect and increases the likelihood of someone doing the wrong thing. Phobias rarely seem to be useful either. I've never met anyone, anywhere, with a mosquito phobia for instance (which you might expect to be quite a useful thing to have evolved) or an irrational fear of pointy things but put a harmless snake in front of many people or put them on a perfectly safe ledge up in the air and everything goes wrong. Bizarre. Sean.hoyland - talk15:39, 4 October 2011 (UTC)[reply]
Evidence and experience are both not hardwired in a brain. From personal experience "doing the wrong thing" is not what you do. People with acrophobia trying to jump over the fence sounds like a urban legend to me. I do have a mosquito phobia and so do you. If a mosquito touches you, you're not going to think "in this area it won't carry malaria so I'll just let it feed on my blood". You smash it the moment you see it landing. That's pretty close to a phobia to me, except that because everyone has the same phobia it's not called one. The fear of pointy things may not be observed a lot, but pointy things are usually not that lethal. To differentiate between harmless snakes and the ones that kill you is quite a job whereas just running away when you see any snake is easy. That's perfectly rational, like not eating any mushrooms because some of them might kill you and it's not worth it to find out which. Washing your hands is a wise thing to do, washing them 200 times a day is not. I think a fear of heights is perfectly rational too, till a certain level. Being afraid that the structure you walk on might fail is wise, but rationality is gone when one, like me, is afraid the Eiffel Tower could collapse because you feel movement.
Anyway, my own acrophobia nor fear of flying was a reason to start this topic. My job does not involve meeting people at 300 ft and I'm perfectly happy driving to France for a holiday. I'm just wondering if the psychologists have been looking at the right thing. A skyscraper at 300ft is scary, a hill at 300 ft is not. It's not the height itself, it's the building. Joepnl (talk) 23:42, 4 October 2011 (UTC)[reply]
"because everyone has the same phobia it's not called one" is a good point. I'm curious whether someone has measured the error rates, completion times etc for people walking along something like a 20cm wide, 5m long straight path at various heights to see whether the error rate is flat, increases or decreases with height. Nevertheless, attachment to the ground does seem to play some kind of role for many people. Being on a balcony in a tall building seems to feel different from being in a hot air balloon. Maybe the brain can't deal with not being attached to the ground and it just treats it like being in deep water for lack of a better hardwired model. Sean.hoyland - talk06:10, 5 October 2011 (UTC)[reply]
I am working to put together a simple list of “Open Questions in Science”, as topics for speakers at a Science Club to which I belong. They would be ones of some interest to professionals and the general educated public, and cover all fields. To give you an idea, here are ones I have nominated already:
1. What is dark matter, and does it really exist?
2. What is dark energy, and does it really exist?
3. How did Neanderthals become extinct, and are we really related to them?
4. Did an asteroid impact really wipe out the dinosaurs?
5. How did our Moon come to be? (this one has recently been regarded as settled).
6. Is time travel theoretically possible?
7. How do new species emerge from the old species to which they belonged?
8. Could we engineer our bodies to become immortal?
9. Why do we see no evidence of extraterrestrial life?
10. Is the general form of our Solar System common or rare?
11. Are quantum computers really possible?
12. Is faster than light travel possible, or is it forever prohibited?
That is more like a pop-culture list than what I would expect from scientists in their fields. 3,4,5,and 7 have consensus answers. Six, 8 and 12 are perennial fantasies, although immortality in some form is theoretically possible with enough time and resources to develop and apply the methods. Eleven is an engineering program. The answers to 9 and 10 need more data, but look at Fomalhaut b for recent evidence of Borg activity.
Some better questions might be:
A Is the replicating molecule or the lipid-membrane first model of life's origin correct.
B Are all human languages descended from a common source, and can it or its daughters be partially reconstructed?
C Why is gravitic mass apparently equal to inertial mass?
D Are the physical constants arbitrary, or mathematically necessitated from self-evident principles?
Is our system of nucleic acids one of only a few possibilities for life during evolution, or are there many ways just as good or better for life to use to store its genetic information during its early evolution?
Do alien ecosystems develop the species concept like Earth did? If they evolve species, do they resemble those on Earth? Do they develop plants and animals? Trees have evolved many times here - did similar-looking autotrophs evolve elsewhere? Is bilateral symmetry inevitable? Do quadrupeds, segmented organisms with many legs, bipeds, birds, snakes evolve on other worlds?
How did the laws of logic, mathematics, and physics come to exist? Why is mathematics so detailed? Could another cosmos have different values for pi and e, different arithmetic, different theorems in predicate logic?
Both a person and a video of a person appear to talk, experience stimuli, think and feel. But the video playback is believed incapable of sensation. If you develop the computing system playing the video sufficiently, is there some level of complexity in the computer algorithms controlling the video that can make it so that it becomes capable of feeling? If not, if any arbitrarily complex computer program is never capable of "real" consciousness, what distinguishes brain matter from the computing system in this regard?
The biggest open, obvious, super-important question that I can think of — one that we as of yet have still only groping ideas of even how to approach — is What is consciousness? How does it emerge? How does it work? To me there are few problems of such severe importance as the hard problem of consciousness, and yet after centuries of research, we still have only glimpses as to the answer. --Mr.98 (talk) 23:15, 4 October 2011 (UTC)[reply]
From the realm of meteorology, "Why/How do tornadoes form?" is a pretty big one that is yet unsolved. See Tornado#Ongoing research. If that question could be definitively answered, it would be much easier to forecast where and when tornadoes would hit, possibly eventually leading to the development of Warn on Forecast for tornadoes. Ks0stm(T•C•G•E)23:33, 4 October 2011 (UTC)[reply]
OP myles325a back live. Thanks all, for a great list, it's more than a beginning. I have one, philosophical AND scientific of my own.
PROB: Are all causative agents ultimately reducible to fundamental physics, or can laws governing reality somehow emerge at higher levels and possess a structure which is not defined by laws at a lower level? This is one of those problems, like the possibility of extra terrestrial life, in which either a yea or nay answer is equally astounding. If all phenomena are reducible to quantum physics, then the Weimar Republic is explicable in those terms, and a better understanding of particle physics will make for a better understanding of the history of that Republic. If it is not, then that means that laws can emerge as higher levels come into being. But how can such a thing operate?
I think Wnt's point, above, on AI, is spot on. Consciousness may very well be an emergent property of complexity (and it would be hard to imagine a conscious matchbox) but if complexity is NECESSARY, is it also SUFFICIENT? That is the rub. For I can imagine very complex machines which might not be conscious, say one that controls air traffic all around the world. Myles325a (talk) 01:05, 5 October 2011 (UTC)[reply]
No-one seems to have touched number 6 on the OP's original list. Time travel into the future is just a problem of engineering now, as a consequence of relativity. See Twin Paradox for a good example. I know that probably isn't what you had in mind but it could have been worse. After all, everything that we interact with on a daily basis is traveling though time at a rate of approximately 1 second per second. A big open question in physics is the search for a "theory of everything", and indeed whether there is one. Teshmanesh (talk) 15:16, 6 October 2011 (UTC)[reply]
I would narrow Mr.98's question of the nature of consciousness to the question of what is the nature of and mechanism behind sense qualia. That is, what, exactly causes "bare" sensations like hot, sulfurous, soft, red, middle C, sweet, and painful and sleepy to be what they are and different from each other. That's the nut to crack--the higher level stuff supervenes on qualia. μηδείς (talk) 03:03, 7 October 2011 (UTC)[reply]
Maximum weight per unit surface area that water can support
Small objects can float on the surface of water due to finite surface tension. Suppose one makes a platform of a few square meters consisting of billions of nanotubes a few nanometers apart as the support. Would such a platform support a few million kg/m^2 as one would expect from the total length times the surface tension, or wouldn't this work? Count Iblis (talk) 04:24, 4 October 2011 (UTC)[reply]
No, it would not work. You got your nanotube surface density calculation wrong. All you would accomplish, is to trap a film of air underneath the platform, but it will still sink. Plasmic Physics (talk) 04:41, 4 October 2011 (UTC)[reply]
It could work, but there are some serious changes that needs to be made, and it is highly impractical with current technology. I'll go into it a bit later. Plasmic Physics (talk) 04:53, 4 October 2011 (UTC)[reply]
Essentially, surface tension keeps a single nanotube afloat, if a sufficiently large weight is applied to a nanotube, it will sink. A cluster of nanotubes is kept afloat by having a lower density than water, provided by a thin film of air trapped between nanotubes closer than the critical radius by surface tension. The more air can be trapped the lower the density, this can be accomplished by altering the length of the nanotubes, or by using multiple layers nanotube clusters. Frankly, it's chheper to glue layers of aerogel to your platform. Plasmic Physics (talk) 05:58, 4 October 2011 (UTC)[reply]
... and, of course, "a few million kg/m^2" is completely unrealistic. Nanotubes, however clever they are, cannot overcome Archimedes' principle, so you would need to displace "a few million kg" of water to provide the buoyancy. Surface tension only modifies buoyancy by moving the displaced water further away from the object. It doesn't provide a force independent of buoyancy. Dbfirs07:41, 4 October 2011 (UTC)[reply]
But surface tension can provide a force in the absence of gravity, showing that the two mechanisms are indeed independent. Robinh (talk) 18:41, 4 October 2011 (UTC)[reply]
Yes, I wasn't suggesting that surface tension is not an independent force, just that its role under gravity can only be to modify the distance to which a fluid is displaced. It is a force between molecules, so has no net large-scale effect. Archimedes' principle rules buoyancy. I suppose that surface tension can also provide a "downwards buoyancy force" by lifting a liquid upwards against gravity. I agree fully with the analysis by Plasmic Physics above, except that I would add that the buoyancy of the nanotube is provided ultimately by the weight of water it displaces. The surface tension acts only as an intermediary force, upwards on the nanotube and downwards on the displaced water. Dbfirs07:28, 5 October 2011 (UTC)[reply]
In solution, copper (II) ions form more stable bonds with water, likely due to the greater charge density (2+ vs. 1+ over essentially the same volume), thus forming stronger bonds with the Solvation shell. Copper (I) ions tend to disproportionate in water, as the difference in energy between the solvation of copper (II) and copper (I) ions is greater than the energy needed to transfer an electron between two copper (I) ions to cause the disproportionation to occur. At least, that's the opinion here: [21]. This page: [22] has a discussion of Copper (I) chemistry and how to avoid disproportionation. This page here looks at the disporpotionation of copper (I) from an electrochemical/thermodynamic point of view. The disproportionation reaction has a positive Eo value, which means that it is thermodynamically spontaneous. It is apparent that the existance of the radical is not the predominant factor in determining the stability of a species in this case. (And in other cases as well. The ground state of O2 is Triplet oxygen, which is a diradical.) --Jayron3213:13, 4 October 2011 (UTC)[reply]
Copper (II) is more stable than copper (I) in nearly all conditions, given a long enough time frame nearly all copper (I) compounds will eventually (and in solution, usually rather quickly) disproportionate; this can be of a long enough time frame to create metastable copper (I) compounds which remain long enough to be useful for long times, however thermodynamically the disporportionation of copper (I) into copper (II) and neutral copper is always spontaneous. The Jahn–Teller effect doesn't deal with the overall stability of these ions, it is pretty much unrelated to the OP's question. That effect deals with the shapes and symmetries of coordination complexes of some metal ligands; it applies to copper (II) because of the radical nature of copper (II) prevents complexes of copper (II) from assuming certain types of symmetry. That has nothing to do with the overall stability of copper (II) vis a vis copper (I) which is an unrelated problem. --Jayron3213:33, 4 October 2011 (UTC)[reply]
TenOfAllTrades:By more stable, I mean at a lower ground state. I understand that diradicals are more stable than monoradicals, but not why this monoradical is more stable than the nonradical. It is to me like someone saying that Ga•4+ is more stable than Ga3+, we all know it's not, but that's point. My logic tells me that it should be energetically unfavourable to remove a second electron from Cu+, but it is not. (proven by experiment) Plasmic Physics (talk) 23:07, 4 October 2011 (UTC)[reply]
I think, Plasmic, the mistake you are making here is assuming that a single variable (paired vs. unpaired electrons) is the sole variable when determining the relative "stability" of two species. It is true that, in many situations, radicals are often less stable than those situations where there are no unpaired electrons; but not always (the example of dioxygen is important to consider here) and can't be handwaved with "but it's a diradical". If the only consideration were the presense of unpaired electrons, dioxygen would have all of its electrons paired. There are obviously other factors at play which can make radicals more stable than non-radical analogues. Arguing that copper (I), a nonradical, should be more stable than copper (II), a radical, ignores an important bit of evidence called "reality". If your assumptions don't match reality, then it isn't reality which is incorrect. --Jayron3200:12, 5 October 2011 (UTC)[reply]
I don't really have an answer yet, having a positive Eo value is consequencial rather than casual. The disproportionation of Cu+ is consequencial of its relative instability compared to the products. What is at the root of it all? Plasmic Physics (talk) 22:05, 5 October 2011 (UTC)[reply]
Actually I had taken this photo in Malaysia, and the size is like a thumb's size(you can also compare it with the structure of the moss). Thanks for the information.--Inspector (talk) 08:46, 5 October 2011 (UTC)[reply]
Ah, then it's very likely to be C. sulcipes :) There are several pictures of them also from Malaysia on the internet. I have requested a rename of the file.-- Obsidi♠nSoul11:25, 5 October 2011 (UTC)[reply]
firing a blank
The old story goes that when someone is executed by a firing squad, one of the rifles contains a blank and the rest contains live rounds. Supposedly this is done so that each firer will have some doubt whether he fired a bullet killing the condemned. However, since the gun is not actually sending a projectile out, but only the firing gasses, I would think that he would know he did not fire a bullet because the gun would not recoil nearly as much. I myself have never fired a blank round, but is my supposition correct here? Googlemeister (talk) 13:37, 4 October 2011 (UTC)[reply]
It depends on the type of blank and the rifle used. For example, you cannot fire a blank from an M-16. The gas will escape and it will not push the bolt back. So, the M-16 requires a blank firing adapter to trap the gas in the barrel. It would be very obvious if you had a BFA on your rifle. But, the recoil would be similar because the recoil you feel is used to push the bolt back and, if the recoil of the blank+BFA is capable of pushing the bolt back, you feel it. Ignoring semi-auto gas-powered rifles like the M-16, consider gunpowder rounds in a standard rifle. If you have a round with just gunpowder, it doesn't kick very hard at all. If you use a wax round, you get a reasonable kick compared to a live round. It depends heavily on how intact the wax is as it escapes the rifle barrel. So, by using good wax, you can create a dummy round that won't kill anyone at a distance, but will kick reasonably well. There are also paper rounds - often used in movies.The paper burns up in the air, but still allows for a reasonable kick. My experience is that the paper rounds don't kick as hard as the wax rounds. So, if I was trying to fake a real round, I'd use wax. -- kainaw™13:59, 4 October 2011 (UTC)[reply]
I can say both from personal experience and from my knowledge of physics that a weapon with a BFA (blank fire adapter) will not have anywhere near the same recoil as a when you fire a live round. The recoil you will feel comes from the conservation of momentum, and for a given weapon it depends on the weight and forward velocity of the bullet and the gases as they leave the muzzle (or BFA as the case may be). Blank rounds for military use often have a plastic bullet that's much lighter than a live one. The plastic bullet disintegrates in the BFA and leaves the weapon with a pretty low forward velocity. The lower weight and velocity makes for a weaker recoil. Yes, the BFA traps the powder gases for a short while so there's a force that acts on the bolt and pushes it back, but there's also a forward force acting on the BFA from the bullet and gases hitting it and those forces nearly cancel each other out.Sjö (talk) 17:57, 4 October 2011 (UTC)[reply]
None of the blanks I used in my M-16 had bullets of any kind. They were regular rounds with the bullet removed and the case crimped shut. There are obviously many kinds of blanks with very different results. -- kainaw™18:15, 4 October 2011 (UTC)[reply]
I've never fired an M-16 with a BFA so I guess it's possible that the recoil for that weapon is roughly the same with or without the BFA.Sjö (talk) 18:30, 4 October 2011 (UTC)[reply]
Although there have been very few firing squads since the introduction of automatic or self-loading rifles - at least in countries civilized enough to worry about the guilty conciences of the participants. The last person shot in this way by the British Army seems to have been a German spy called Josef Jakobs who was shot in 1941 in the moat of the Tower of London, presumably with standard Lee Enfield bolt-action rifles. Alansplodge (talk) 23:22, 5 October 2011 (UTC)[reply]
Gary Gilmore was executed by firing squad in 1977, and according to a source in the article [26] one of the rifles was loaded with a blank. I'd also like to point out that you can easily fire a single blank round in a self-loading weapon, but it won't reload due to the weaker recoil and gas pressure.Sjö (talk) 10:32, 6 October 2011 (UTC)[reply]
Of course, but if the point is to camouflage the fact you fired a blank, the firearm would need to behave as normal, which would mean the self loading would need to take place. Googlemeister (talk) 13:31, 6 October 2011 (UTC)[reply]
While an experienced marksman can tell the difference between a blank and a live cartridge based on the recoil (the blank will have lower recoil), there is a psychological incentive to not pay attention and, over time, to remember the recoil as soft.[citation needed] In more recent times, such as in the execution of Ronnie Lee Gardner in Utah in the United States in 2010, a rifleman may be given a "dummy" cartridge containing wax instead of a bullet, which provides a more realistic recoil.[1]
It's sourced and wax bullets were also used in the execution of John Albert Taylor in 1996. On the other hand [27] calls in to the question how well wax bullets stimulate a live round. Other sources like [28] which aren't discussing their use in executions mention wax bullets tend to have low recoil. Of course those generally rely on experiences with normal wax bullets. From [29] it's apparently a specially designed wax bullet which was tested to be difficult to distinguish. How this is done isn't really explained (since I believe the lower mass is one of the problems) although in the earlier ref there were some suggestions (although it would seem to be problematic to weight a bullet if you want to be reasonably sure it remains non lethal).
Imagine I was building an oceangoing vessel (I'm not, this is purely hypothetical, but it helps to make the question less abstract). I would like to make the windows in my imaginary wheelhouse proof against being broken in a very severe storm. The damage they need to resist could come either from the pure weight of water, or potentially a point impact from items on deck being thrown against the windows. It's not really possible to model those forces, so instead I set my hypothetical design requirement to be that the windows mustn't be any weaker than the metal structure of the wheelhouse itself. The wheelhouse is made of aluminium, whatever grade is commonly used for such purposes. As a finger in the air, let's say it's made of 10mm plate. Each window is perhaps 2 feet by 2 feet.
The glass can be toughened, laminated, whatever technology is available, but it does need to behave like "real" glass, eg not scratch like plastic windows. Since it is to be fitted to an imaginary vessel, cost is not really a concern, but the suspension of disbelief probably doesn't extend to really exotic materials costing hundreds of thousands.
Is it feasible to have a window that is as strong as the wheelhouse in this way? What material would it be made of, and how thick would it have to be?
Energy absorbed by brittle (red) and ductile (blue) materials before breaking You can certainly increase the strength of glass by laminating or tempering it, but I'm going to venture a guess that achieving equivalent strength of the structure (by the way, most oceangoing ships are made of steel, not aluminum) is probably not feasible without a very, very thick pane of glass. The reason is the difference in the Resilience of glass and metals (i.e. the amount of energy that can be absorbed before breaking)--glass is very brittle, while metals are more ductile, so metal can absorb much more energy before breaking. This is commonly cited as one of the reasons the Titanic sank-- the steel that composed the hull was much more brittle than it should have been, which was exacerbated by sailing in the cold waters of the North Atlantic. Mildly MadTC16:38, 4 October 2011 (UTC)[reply]
According to our article on AlON, your 2'x2' window pane could be made at a cost of around $5-10k each. I don't know if strictly speaking it is a strong as aluminum, but it seems like it is very good at impact resistance. Googlemeister (talk) 18:31, 4 October 2011 (UTC)[reply]
I'd go with coated polycarbonate, to get both polycarbonate's impact resistance and the coating's scratch resistance. There's a reason why it's used for things like airplane canopies and bulletproof glass. --Carnildo (talk) 01:07, 5 October 2011 (UTC)[reply]
Thanks for your answers - must admit I'd hoped someone might find some specific figures from a manufacturer or engineering databook :-). I'll look at the general references though.
For what it's worth, aluminium upperworks are not uncommon on smaller vessels even when the hull is steel - helps keep the centre of gravity a bit lower. --Pete — Preceding unsigned comment added by 93.97.184.230 (talk) 20:54, 5 October 2011 (UTC)[reply]
What makes a material tough from a molecular point of view?
On one hand, you have ceramic which is hard, but brittle. On the other hand you have metal which is ductile, but not as hard as ceramic. Is it possible to model on a computer, an arrangement of atoms and say, "yeah this would give it characteristics of both"? ScienceApe (talk) 21:13, 4 October 2011 (UTC)[reply]
To some extent, the ability to resist impact is diametrically opposed to hardness. However, there are materials, such as metals, which are a good compromise between hardness and the flexibility needed to absorb energy from impacts without fracture. Also, a denser material is able to absorb more force, hence the use of materials like depleted uranium for armor. Another approach to get "the best of both worlds" is composite materials, such as in a Kevlarbulletproof vest. StuRat (talk) 02:18, 5 October 2011 (UTC)[reply]
Young's modulus in metals and fully bound solids like diamond and salts is notoriously difficult to simulate from Schroedinger wave equations because it's heavily dependent on resonances between many if not most of the substance's outer electrons. And the other quantity you ask about, resilience, depends on it. You can have slightly better luck with composites but in general they are much weaker and more brittle, and when they aren't, as in carbon fiber composites, you run in to the same problem. 69.171.160.19 (talk) 04:10, 5 October 2011 (UTC)[reply]
Irish winters
What were the causes of the cold winters that hit Ireland and other countries in europe to get a cold winter of during 2009-10 and 2010-2011 is this likely happen again this year at the same severity or much worse. --86.45.141.20 (talk) 21:15, 4 October 2011 (UTC)[reply]
No. See Winter of 2010–2011 in Great Britain and Ireland; "During the latter part of November, northern blocking established over Greenland which resulted in the Jet Stream moving south, allowing cold air to flow in from the east." The Winter of 2009–2010 in Europe: "Globally, atypical weather patterns brought cold, moist air from the north. Weather systems were undergoing cyclogenesis from North American storms moving across the Atlantic Ocean to the west, and saw many parts of Europe experiencing heavy snowfall and record-low temperatures."Alansplodge (talk) 23:04, 5 October 2011 (UTC)[reply]
What's the maximum distance an electron can be from the nucleus before the value of the probability distribution is 0? Or is it always positive (though very small)? --99.119.63.240 (talk) 21:32, 4 October 2011 (UTC)[reply]
An electron will have positive probability almost everywhere including at arbitrarily large distances (though the probability decreases exponentially towards zero with distance). Dragons flight (talk) 21:36, 4 October 2011 (UTC)[reply]
Sort of. Except that would assume that you could identify an electron at a single location which you cannot. Saying (in a quantum sense) that the probability of finding an electron at any given distance from the nucleus is nonzero is not the same thing as finding a discrete ball of negative change just hanging out at a point in space at that distance. The electron would have to actually, you know, exist as a discrete ball which stays still at that point. Also, as electrons are nondistinguishible, detecting an electron with an actual detector gives you no information as to the actual specific atom that is the source of that electron. So, you actually can't extend the probability distribution given by the wavefunction into a real chance of finding a specific electron (such as say, the ground state electron of a specific atom of hydrogen) at a specific distance from the nucleus. There's just no way to do that, in an empirical sense. --Jayron3202:57, 5 October 2011 (UTC)[reply]
Yes, one can observe this indirectly. If you put an atom in a constant electric field, then it has a finite ionization probability, no matter how weak the electric field is. The physical reason for this is that there is enough energy to ionize the atom if the electron moves a large enough distance. But this does mean that even in the ground state, the electron can be arbitrarily far removed from the nucleus. If the wavefunction were such that an electron is always less than some distance d from the nucleus, the ionization probability would become zero already below some nozero electric field strength. Count Iblis (talk) 23:40, 4 October 2011 (UTC)[reply]
Previously in 2008 on the Ref Desk or in the article Atom we discussed an experiment in which an atom was isolated, and energy was pumped into it until the electron was at a ridiculous distance from the nucleus, like a millimeter. The phenomenon was derided as being merely was something like a "Rydberg atom" without clarifying how it was not a "true atom." The archives of the article are not responding, so I cannot cite the relevant revisions other than [30].Edison (talk) 05:04, 5 October 2011 (UTC)[reply]
We do have an article about the Rydberg atom (cool (sorry:) bit of physics!). The comment appears to have been removed from Atom with this talk-page discussion. I disagree with that, now that there are multiple papers (heck, a whole cited article about the phenomenon)...not for WP editors to judge whether it's "a real atom" if that's what WP:RS call it. Can certainly improve the wording to be more WP:V correct numerically, etc. DMacks (talk) 18:04, 5 October 2011 (UTC)[reply]
Wardens
My question for the community to investigate is, "Do wardens execute criminals?" I have attempted to respond accurately to this science question, but I CANNOT DO IT! Can someone in the community PLEASE help me? — Preceding unsigned comment added by 24.0.70.91 (talk) 22:53, 4 October 2011 (UTC)[reply]
The warden gives the final order for the execution to proceed (indicating, among other things, that there's been no reprieve). To that extent, he/she is a participant in the execution: even though someone else sets up the IVs and pushes the button, the warden is the one who, in the end, says "push it". -Nunh-huh01:52, 5 October 2011 (UTC)[reply]
Yes. The OP seems to be using warden in its sense of any prison guard while the answerers seem to be using the (apparently mainly American) definition meaning only the boss of the prison. Certainly in most cases a prison employee is the executioner. Rmhermen (talk) 14:08, 5 October 2011 (UTC)[reply]
Yes, I was confused over the meaning of the term used in the question. In the UK, a prison officer is a warder not a warden. Dbfirs20:58, 5 October 2011 (UTC)[reply]
Whether you call him a warder or a warden, if he's executing anyone in the UK, I'd say he's improvising rather dangerously. - Nunh-huh05:03, 6 October 2011 (UTC)[reply]
Clinton Duffy was the Warden for 12 years at San Quenton prison, and suoervised the execution of 90 people. In the US, it has been common to establish continuous communication with the state Attorney General and Governor to make sure there is no impediment such as a stay from a judge or a pardon or stay from a Governor. The Warden would arrange for an executioner and for the means of execution (gallows, firing squad, electric chair, gas chamber, lethal injection). He decides on the exact time of execution. He would arrange for a physician to pronounce the prisoner dead. He would ascertain that there was a valid execution order. He would arrange for a Priest or spiritual adviser if the condemned prisoner requests one. He would arrange for witnesses (friends or family of the condemned, victims' family, citizens and press). [32], [33], [34]. Edison (talk) 22:52, 5 October 2011 (UTC)[reply]
October 5
Why are impact craters on Moon all circular?
This came up at a Science Meet where an exponent of non-Standard Model of the Universe (to wit: Electric Universe) declared that these formations were volcanic in origin, and were not impact craters. He cited in evidence that if they were impact craters, then many would be like skid marks, from asteroids which came in obliquely. There were other criticisms of the asteroid theory, but they were quite technical. Otoh, the objection to craters in that they are all too circular and neat caused me to raise my monobrow like a big hairy boomerang. What do you think? Myles325a (talk) 01:14, 5 October 2011 (UTC)[reply]
The energy released at the point of impact converts to heat, causing debris to expand in all directions from that point. There will also be a few skid mark craters that are elliptical in shape due to glancing blows. Did you read Impact crater? Graeme Bartlett (talk) 01:41, 5 October 2011 (UTC)[reply]
I believe the maria are ancient lava flows, so volcanism did occur early on. Here's an example that looks like a skipping meteor blow to me, in the lower left corner: [35]. Also, if the meteor skips enough, it may make a shallow impact over a wide area rather than a single deep crater. That type of shallow crater is likely to be obscured more quickly by volcanism, dust, and later meteor impacts. StuRat (talk) 01:50, 5 October 2011 (UTC)[reply]
Reaching back into the inventory of everything I ever read, some fictional work about space exploration asserted that if you spread a layer of flour on a countertop, then throw little round dense objects (lead shot? peas?) at it vertically or at any conceivable angle, every crater is observed to be circular. Intuitively, I would have expected a vertical drop to produce a circle, but a 45 degree angle to produce an ellipse. Edison (talk) 04:53, 5 October 2011 (UTC)[reply]
There are young craters with asymmetric ray systems such as Proclus (crater) suggesting an oblique impact. I don't understand how the person who is suggesting a volcanic origin proposes to explain the extensive shock deformations you can see in lunar samples. Sean.hoyland - talk05:49, 5 October 2011 (UTC)[reply]
Apparently the answer is most, but not all are circular. Please see Impact crater#Crater formation, "Since craters are caused by explosions, they are nearly always circular – only very low-angle impacts cause significantly elliptical craters." Ref. Melosh, H.J., 1989, Impact cratering: A geologic process. New York, Oxford University Press, 245 p.' The same section of the article also has a video of "a laboratory simulation of an impact event and crater formation" (apologies to Graeme Bartlett, who I now see has referred you to the same article.) • Here is an Australian Broadcasting Corporation (ABC) webpage on the question, Are impact craters always circular? - 220.101talk\Contribs08:44, 5 October 2011 (UTC),[reply]
If I were to have a sheet of say, aluminum that was a 2-inch square and 1 atom thick, would I be able to see it by looking at it from the "square" side? If so, would it look any different from the kind of aluminum foil that comes on a roll? (other than the fact that it appears much thinner) Assume that variables that could damage the foil (oxidation, corrosion, wind, etc.) are nonexistent. Hmmwhatsthisdo (talk) 06:34, 5 October 2011 (UTC)[reply]
It would be completely transparent at optical wavelengths (except for a few sharp faint frequency harmonic bands that you would be completely unable to discern.) The atomic radius of aluminum, 1.4 angstroms, is less than 1/2,500th the wavelength of visible light. Also it would spontaneously disintegrate due to unavoidable Brownian motion of the air, which isn't wind. 69.171.160.19 (talk) 07:03, 5 October 2011 (UTC)[reply]
It spontaneously disintegrates in a vacuum too, just as fast, due to inherent mechanical strain of the vibration of room temperature heat. There is essentially no cohesion of metals an atom thick. They might as well be molten as far as they act. 69.171.160.19 (talk) 07:28, 5 October 2011 (UTC)[reply]
I've made a <5 nm (50 angstroms) bismuth nanofilm in the lab before. It's very translucent, and has infinite resistance (whereas a 20 nm nanofilm conducts a decent amount of electricity -- a small piece would have had a resistance of about 500-1000 ohms). elle vécut heureuseà jamais (be free) 05:08, 6 October 2011 (UTC)[reply]
Height Increase
I have heard that height of a human being can be increased artificially by a painful surgery. Is it possible? Please give the name of it. — Preceding unsigned comment added by 119.235.51.130 (talk) 14:16, 5 October 2011 (UTC)[reply]
It's worth interpreting that number cautiously. It looks like the publication there may be the abstract of a conference poster or talk, so I don't know if it's possible to readily get hold of the full data, but the abstract has some relevant information. Of the 151 'complications' captured in their study, 78 (52%) fell into their Grade I: Benign complication without any unexpected surgery or anaesthesia. Only 14 (9%) fell into the highest Grade III: Severe complication category. Still not what I would call a safe or worry-free procedure by any means, but not quite the unmitigated disaster that one might infer from a 100% complication rate. TenOfAllTrades(talk) 14:15, 7 October 2011 (UTC)[reply]
The phylogeny of the flowering plants, as of APG III (2009).
It's not just catnip really. Those (unranked) 'ranks' above the ordinal level in plants are clades, which do not actually have taxonomic ranks. This is because all plant articles in Wikipedia follow the modern APG III system of the Angiosperm Phylogeny Group. This system is more accurate than the old Linnean system because it uses molecular genetic data for grouping plants. Remember that the Linnean system was established before the discovery of evolution and the DNA. So they were traditionally and inaccurately grouped simply by morphological and biochemical characteristics.
For example, flowering plants (angiosperms) were once grouped into two classes - Monocotyledons and Dicotyledons based on the number of cotyledons. Obviously this is a rather unreliable way to classify plants. APG discovered that though monocots are monophyletic (that is, they are all descendants of a common ancestor), dicots are not. Though most dicots are monophyletic (now grouped into the clade Eudicots - 'true dicots'), not all of them descended from a common ancestor. Magnoliids, for example, exhibit two cotyledons and have been traditionally classified under dicots, but they actually diverged earlier than eudicots (see phylogenetic tree on the right). Some genera, like Amborella, are also basal (arising earlier than other clades) and thus can not be classified under any of the traditional orders (as of APG III, the single species of the genus has been classified under their own order, separate from the rest). Others are simply not well understood like members of the family Sabiaceae, etc.-- Obsidi♠nSoul04:07, 6 October 2011 (UTC)[reply]
I don't think it is true that all Wikipedia plant articles use the modern system, although that is probably a goal -- at the moment there is still a lot of variability. Looie496 (talk) 14:53, 6 October 2011 (UTC)[reply]
It's preferred (in angiosperms at least), like animal and microbio taxonomy, there's always disagreement on which should be in which among specialists. Add to that good faith editors that use outdated classifications (bananas and plantains for example, were still classified as Musa × sapientum and Musa × paradisiaca a year ago... :/ Using autotaxoboxes helps standardize things at least, though there are necessary exceptions. -- Obsidi♠nSoul19:23, 6 October 2011 (UTC)[reply]
I have not tried to do that. I have run a 3 phase motor on 2 phase power. That is not very uncommon. When the only power available is 1 phase power, a static 1 phase to 3 phase power converter will produce 3 phase power to get a 3 phase motor started. Then, the static converter will drop to 2 phase power to continue running the motor (yes, this can damage 3 phase motors not designed for 2 phase power). I don't see how a single phase will keep it rotating under any load. Unlike a single phase motor, a three phase motor doesn't have a capacitor to rotate the incoming power and create a second phase (technically, single-phase motors convert the power to 2 phase power internally and are really 2 phase motors). It is possible that some very fancy three phase motors are internally six-phase motors (using the same technology as a single phase motor). Then, I'd be certain that if you got it started, you can keep it spinning on a single phase of power. -- kainaw™13:19, 6 October 2011 (UTC)[reply]
I've seen three phase motors burn out when only single phase power is furnished to them, but I cannot rule out some motor being capable of being internally rewired to allow single phase operation, perhaps at a reduced HP. I remember hearing one three phase motor driving ventilators slowly wind down over perhaps a 2 minute period when it was single phased while running. It burned out due to the prolonged overload. Engineers have gotten in trouble for failing to provide protection for a motor against such single-phasing, when they specify the protective circuit for a large motor. If the motor is spun up with 3 phase, then "Alternating current fundamentals" by Herman says it will continue to turn if only one phase is powered, with a "greatly reduced capacity." It would overheat and burn out if it were called on to operate the full 3 phase load on 1 phase. A single phase applied to a stopped 3 phase motor would not produce the phase shift or rotating magnetic field needed to start it turning. The question was a bit fuzzy. Did the OP mean "Could a 3 phase motor also be wound with a single phase winding, along with provision for a capacitor?" If so then the answer is likely "Yes." It would not seem efficient or economical to build motors with that capability. Here is an account from 1918 of how someone added an external phase splitter to start a three phase motor, which was then switched to operate direectly from a single phase source when it got up to speed. Edison (talk) 18:41, 6 October 2011 (UTC)[reply]
A three phase motor operated from single phase can also be used to produce the missing phases, and thereby power other three phase motors, or produce dangerous and unexpected backfeed on the phases thought to be dead, endangering utility workers. Edison (talk) 15:43, 7 October 2011 (UTC)[reply]
homology / analogy of env viral coat proteins, across mammals and Drosophila
I'm designing the beginnings of a selective intercellular transport protocol, and I'd like to take advantage of some of the interesting properties exhibited by HIV env (perhaps make a pseudotype). I note that Drosophila has some endogeneous retroviruses, such as gypsy which too, codes for an "env-like" protein. However, when I actually do a BLAST search between gypsy env and HIV env, the alignment is quite poor, on both a protein level (for gypsy open reading frame 3, which codes for env, and HIV gp120 / gp160 etc.) and a nucleotide level -- often the query coverage is less than 20%. How possible is that HIV env and gypsy env would just keep a few conserved domains and rapidly mutate all the non-critical domains, and that BLAST scores aren't useful for detecting homology between retroviruses of distant species?
Other than the receptors, are there significant differences in the mechanisms of HIV-1 env and gypsy env? Could I use HIV env in Drosophila? This is because the required receptors on the target cell required for gypsy env to induce efficient infections remain poorly-characterised, unlike the receptors/coreceptors required for HIV env. elle vécut heureuseà jamais (be free) 05:05, 6 October 2011 (UTC)[reply]
It may be difficult to identify homology, particularly if the entry process has diverged substantially (i.e. if very little homology exists). For a search like this, I would expect PSI-BLAST (PMID 9254694, available as an algorithm choice on the BLAST page) to be more useful for your purpose than BLAST. PSI-BLAST forms a PSSM from BLAST results, and uses the highest-scoring positions in an iterative BLAST search - it's a remarkably powerful process! -- Scray (talk) 02:05, 7 October 2011 (UTC)[reply]
Eating "unpleasant" foods
There are many foods that people eat routinely that are in some sense "unpleasant", such as spicy, sour, and bitter foods. Many of these contain chemical irritants that "burn" your mouth or otherwise might discourage some people from eating them, and yet many of us (myself included) enjoy eating them frequently. Presumably such qualities originally evolved to discourage animals from eating these plants, though now they are paradoxically the reason that we intentionally cultivate many foods for consumption.
Now, what I am really wondering about is whether the irritants in "unpleasant" foods have an impact beyond the mouth and immediate process of eating them. For example, does eating such foods also tend to irritate the stomach or bowel in a way that can make people more prone to digestive problems such as stomach aches, heart burns, diarrhea, etc? I know people who have given such an explanation for not eating spicy food, but I'm not sure if there is good empirical evidence for this or not. Dragons flight (talk) 07:56, 6 October 2011 (UTC)[reply]
Eating certain spicy foods, irritates the digestive tract. Normally, this is not a problem however, regular consumption of such foods can result in ulceration which may lead to further complications. In fact, it has been proven that daily consumption of curries usually causes the stomach lining to thin considerably. Plasmic Physics (talk) 09:55, 6 October 2011 (UTC)[reply]
[citation needed]. For decades it was believed that alcohol and spicy foods caused peptic ulcers, but that was shown to be a myth wasn't it? [36][37][38]. Our article and those external links generally say that spicy food may aggravate an existing ulcer, but they don't cause them. The last link even suggests that spicy food may partially protect against ulcer formation in healthy people. Since the 2005 Nobel prize was awarded for showing that most ulcers are caused by bacteria, I pretty much assumed that we would be discussing other kinds of digestive problems when I asked the question. Also, where are you getting the curry info from? Dragons flight (talk) 18:59, 6 October 2011 (UTC)[reply]
It's difficult to track down the original research paper, but the main point is that acute gastritis is caused by the phenolic compounds present in "hot" foods, such as capsaicin, this compound induces the secretion of hydrochloric acid in a similiar way that alcohol does. The increased acidity of the stomach acid erodes the stomach lining, and causes inflamation. Curries have a complex chemical makeup, while they contain many healthy chemicals, they also contain unhealthy ones. It's like a candle, oxygen feeds a flame, but if air flow is too great, it extinguishes the candle. The short of it is, moderation is a virtue. Plasmic Physics (talk) 00:57, 7 October 2011 (UTC)[reply]
Within the last ten or so years I read an article about chicken farmers feeding hot pepper to the hens. They (the hens, not the farmers) didn't mind the flavor, it discouraged rodents from eating the feed, and somehow the irritation of the digestive system made the hens healthier. Now when I search for "hen pepper health" all I find are chicken soup recipes. I did find refs for using pepper in bird seed to discourage squirrels, which say that birds do not mind the hot pepper taste:[39]Edison (talk) 15:55, 7 October 2011 (UTC)[reply]
Specifically, Scutigera coleoptrata, or the "house centipede". They look like a little mustache running along. Creepy critters. But supposedly they feed on other, creepier critters. One thing is unclear or unstated in the article: Do they pose any threat to humans? That is, do they bite? Or are they harmless? Does anyone here know? Thank you! ←Baseball BugsWhat's up, Doc?carrots→ 09:39, 6 October 2011 (UTC)[reply]
They don't seem to be considered dangerous to humans. We have the dangerous scolopendrid centipedes (locally known as ulihipan), among which is Ethmostigmus rubripes which can reach a little over six inches in length (compared to one or two inches in American house centipedes). ;) They have the same reputations out here as scorpions (i.e. if you see one inside the house, kill it). -- Obsidi♠nSoul19:47, 6 October 2011 (UTC)[reply]
Centipede bite amazingly .. For the record I was bitten by the European Centipede - not painful like a wasp sting - but very strong - like being kicked by a mule (I never been kicked by a mule so I'm guessing). 87.102.42.171 (talk) 23:21, 6 October 2011 (UTC)[reply]
How might one get bitten by Scutigera coleoptrata? I've seen them skittering along the floor. I've deliberately stomped out the lives of a few, wearing shoes of course. I can't imagine trying to pick one up in my hands. They move too fast to catch. Bus stop (talk) 02:12, 7 October 2011 (UTC)[reply]
A pair of legs on their first trunk segment have been modified into venom-injecting appendages (forcipules). Think of them as poison syringe-tipped hands. This is the origin of the scientific name for their taxon - Chilopoda means "lip leg". Click to see forcipules on Scutigera-- Obsidi♠nSoul09:14, 7 October 2011 (UTC)[reply]
I found myself sharing a bed with one in Turkey once, so I could easily have been 'bitten', although I wasn't. I also managed to catch it in a water bottle and release it in the hotel grounds. Mikenorton (talk) 09:50, 7 October 2011 (UTC)[reply]
I know that the earth's tilted axis is the primary reason that we have seasons, but how much of an effect does the varying day length have? --CGPGrey (talk) 10:07, 6 October 2011 (UTC)[reply]
That might be a bit more detail than an encyclopedia would get into. OR, it might just be that no one has researched it and added it. Obviously, the length of the day has a qualitative effect on both atmospheric and oceanic temperatures. An exact percentage might be hard to come by, as it's liable to vary from season to season, due to factors such as el nino, la nina, and any number of other things. ←Baseball BugsWhat's up, Doc?carrots→ 10:32, 6 October 2011 (UTC)[reply]
Part of the problem is that it would essentially be a 3-dimensional table: One dimension would be the average daily temperature. Another would be the number of hours and minutes of sunlight per day. The third dimension would be the latitude. Obviously, a lot of info, and probably beyond the scope of a wikipedia article. Have you tried googling this subject? ←Baseball BugsWhat's up, Doc?carrots→ 10:38, 6 October 2011 (UTC)[reply]
The inclination of the Earth's axis relative to the Earth's orbital plane causes the cyclic variation in the duration of daylight and solar heating, and this variation causes the seasons. Therefore it is reasonable to say that the seasons are due entirely (100%) to inclination of the Earth's axis. Dolphin(t)10:54, 6 October 2011 (UTC)[reply]
But that's not the whole story, otherwise the coldest day of the year would be the Winter Solstice and the hottest day would be the Summer Solstice (or the opposite in the southern hemisphere). But thanks to seasonal lag, the coldest day of the year is liable to be in early February, and the hottest day in early August, by which time the days are longer than the winter solstice and shorter than the summer solstice, respectively. And besides, the OP apparently wants numbers rather than qualitative observations. ←Baseball BugsWhat's up, Doc?carrots→ 11:00, 6 October 2011 (UTC)[reply]
I agree that the seasonal extreme temperatures don't occur on the solstices, but that doesn't detract from the fact that the Earth's seasonal variations are due 100% to the inclination of the Earth's axis relative to its orbital plane. All other observations, such as seasonal variation in duration of solar radiation and seasonal variation in ocean temperatures, are consequences of the Earth's inclination, not independent causes of seasonal variation. Dolphin(t)11:12, 6 October 2011 (UTC)[reply]
OK. So the simple answer to the OP's question is, indeed, 100 percent. One way to look at it is to look at the extremes. The poles never get warm, but they are not as cold in their respective summertimes when they get 24-hour sunlight, vs. wintertimes when they get none. And at the equator, it's pretty much the same all year around, apart from daily variations due to weather changes. ←Baseball BugsWhat's up, Doc?carrots→ 11:16, 6 October 2011 (UTC)[reply]
I understand that the seasons are caused 100% due to the tilt, but that's not my question. There is increased solar radiation during the summer because the hemisphere is 'facing' the sun, but there is also increased radiation because the duration of exposure is also increased. How much of the increase in solar radiation is attributable to the increase in day length? --CGPGrey (talk) 13:49, 6 October 2011 (UTC)[reply]
Here's a plot of solar irradiance during the summer and winter solstices for 40° of latitude [[43]]. The increase in solar radiation is the area between the two curves. You're asking which fraction of the area is due to the summer curve being higher, and which fraction of the area is due to the summer curve being wider. I don't think that's mathematically defined. 98.248.42.252 (talk) 15:59, 6 October 2011 (UTC)[reply]
Isn't the increased duration of exposure also caused by the axial tilt? The sun is up longer because the hemisphere is tilted toward the sun. thx1138 (talk) 16:46, 6 October 2011 (UTC)[reply]
I disagree with Dolphin's assertion that the Earth's axial inclination is responsible for 100% of the seasonal variations. Because the Earth's orbit is also slightly eccentric, its distance from the Sun varies by about 5,000,000km (about 3.34%) between aphelion (currently around 04 July) and perihelion (03 January), resulting in about 6.9% greater insolation at perihelion. This certainly must have some effect on seasonal temperature variations (ameliorating Northern hemisphere winter temperatures, for example), though as our Earth's orbit article states, the effect is not great compared to that of axial tilt. Nevertheless it is important when considering the Milankovitch cycles. {The poster formerly known as 87.81.230.195} 90.197.66.175 (talk) 13:57, 6 October 2011 (UTC)[reply]
The Earth's tilt is 100% of the reason for the existing seasons, but yes, winter in the Northern hemisphere would be a few % colder (probably only 1 or 2%, depending on what you measure percentages of) if the Earth were at its furthest point from the sun instead of its nearest point. The proportion that is attributable to angle of incidence, compared with the effect day length, will depend not just on latitude but on cloud cover, wind speed and direction, and probably several other factors, so it is unlikely that we can find an answer to the question. We need to decide what we are measuring the proportion of (probably temperature, but this has a fixed point only at −459.67 °F). I wonder if anyone has published any research comparing angle of incidence effect with day length effect. They would be difficult to separate because they are closely related. Dbfirs12:07, 7 October 2011 (UTC)[reply]
oxidation no. in halogens
my teacher said that oxidation no. of Halogens like fluorine and iodine in their peracids is +7 not -1 like HClO4 but i want to know the other peracids which i must calculate the oxidation no. of their halogens by +7 not -1 — Preceding unsigned comment added by Mido22 (talk • contribs) 13:00, 6 October 2011 (UTC)[reply]
Is the local cluster expanding due to dark energy, contracting due to gravity, or at a steady state (by which I mean, whether it's expanding or contracting is statistically insigificant given the margin of error, or that some parts are expanding and others contracting)?
What can this tell us about dark energy and a possible equation for determining the strength of dark matter in a given area? I'm curious if the evidence points to a cosmological constant (i.e., that the vacuum of space necessarily pushes matter apart as an inherent property) or to a scalar field (e.g., a fifth fundamental force, heretofor undetected).
I'm also curious at what point dark energy seems to overpower gravity; am I correct that the equation for gravity is whereas the equation for dark energy is where (part wherein "" stricken; actually, could theoretically be zero or negative Magog the Ogre (talk) 19:16, 6 October 2011 (UTC)) (it seems most likely to me that , but I can't make that assumption precisely)? Magog the Ogre (talk) 16:49, 6 October 2011 (UTC)[reply]
re: Dauto: according to the article dark energy, scalar fields are in fact considered a possibility, with quintessence and moduli considered subpossibilities.
The simplest form of dark energy, a cosmological constant, can be approximately represented as . In other words, the force grows in direct proportion to the separation distance rather than falling off with distance. The effects of dark energy are just barely perceptible on the scale of several billion light years. If dark energy truly has the form given above, then there is no reason to expect that any measurable impact would occur to structures as small as the local cluster. Dragons flight (talk) 19:21, 6 October 2011 (UTC)[reply]
re DF: wait - the force actually expands with distance? That means that a galaxy which is 12 billion ly away is pushing on our planet with greater power than a galaxy at 10 billion ly. If this is correct, wouldn't it eventually mean the disintegration of all matter in the universe? (because, as the universe expands, the distance to massive objects becomes greater, and thus more powerful, such that the forces would become incredibly high... or am I wrong?).
re Tango (not responding inline above; honestly I dislike inline comments because it disrupts the flow): what is the redshift/blueshift of other galaxies within the cluster, how does this relate to their distance from ours, and how is this comparable to other galaxies? I'd think that a measurement of the redshift of these galaxies, versus the redshift of other clusters could give us a pretty good estimation of the scales on which dark energy works. Magog the Ogre (talk) 21:37, 6 October 2011 (UTC)[reply]
Re Magog the Ogre: Quintessence doesn't produce a repulsive force between objects. Not the way you're thinking. We are not being pushed away by distant galaxies. Quintessence creates an expansion of space (In other words, it's a dynamical form of cosmological constant). That's why the further apart galaxies are, the faster they seem to accelerate from us. That happens because there is more space in between to expand. That can be modeled as a repulsive force that is proportional to the distance as Dragons flight pointed out but it isn't an actual force between distant objects. In fact, An actual force between distant objects that increases with the distance would have to propagate faster than light. Dauto (talk) 01:20, 7 October 2011 (UTC)[reply]
Different galaxies within the local group have different redshifts/blueshifts (some of each). There is no correlation between redshift and distance. Redshifts change over time (and change from redshifts to blueshifts and back again) as galaxies move around their elliptical orbits. --Tango (talk) 18:35, 7 October 2011 (UTC)[reply]
Yes, that's right, and as Dragons flight explained above, and I quote "all structures that are not already gravitationally bound will eventually fly so far apart that they are no longer observable". Neither will we be able to see those far away galaxies nor will we be able to fill any force produced by them. They will effectively be beyond the horizon. Dauto (talk) 04:23, 7 October 2011 (UTC)[reply]
More information on the Marbled Lungfish's genome please
I would like more information on the Marbled Lungfish (Protopterus aethiopicus). According to Wikipedia, it has 133 billion base pairs in its genome, which is more than 40x the size of the human genome. My questions are as follows:
How does it fit all of that in each of its cells? Does this animal have any evolutionary adaptations to maintaining such a large genome (wrapping it up more tightly, larger cells on average, more cell space devoted to the nucleus)?
How much of it is junk DNA?
How long does mitosis take for this creature? Any special adaptations for this process?
Disclaimer: I know next to nothing about the genome of the Marbled Lungfish. However, tracing the references from the citation in the artice, the quoted genome size is based on estimates from cell size published in 1972 (here). I can't find anything more recent and it doesn't seem that the lungfish genome is among the 1215 eukaryotic genome projects currently underway. Since the genome size estimates are based on the larger cell size, it appears that the answer to your first question is "unusually large cell size" (1978 article by the same author). Since we don't have an actual genome sequence for the marbled lungfish, the answer to your second question is likely unknown, although based on other genome sequences, there do seem to have been genome duplication events during the evolution of fishes, which might explain its large size. I would predict that the proportion of the genome that is "junk" (terrible term, it just means we don't really know what it does; perhaps plays a structural role or controls gene expression patterns in very complex ways) is somewhat greater than the more compact genomes. I can't find any references that address the last question. The marbled lungfish, as beautiful as it is, does not seem to be one of the favorite model organisms for cell biologists or molecular biologists. --- Medical geneticist (talk) 00:29, 7 October 2011 (UTC)[reply]
Actually a Google Scholar search for "Protopterus aethiopicus DNA" finds quite a bit of stuff, some of it pretty recent. One factor is that the species is apparently tetraploid, meaning that it has four copies of every chromosome instead of the usual two. This recent paper, however, suggests that the quoted genome size value may not be all that reliable -- there seem to be substantial discrepancies between studies. Looie496 (talk) 02:27, 7 October 2011 (UTC)[reply]
Damped oscillations in real life
Why do damped oscillations in real life come to a halt when basic damped oscillations studied in physics/differential equations (such as overdamped, underdamped, and critically damped cases arising from second order linear differential equations with constant coefficients) model oscillations that go on forever, even if with decreasing amplitude? — Trevor K. — 20:27, 6 October 2011 (UTC) — Preceding unsigned comment added by Yakeyglee (talk • contribs)
The model of friction, or other energy-dissipation process in the physics models, is simplified. Also, in real life oscillations below a certain level can't be detected because they are overwhelmed by other motions, electrical noise, or electrical noise and vibration inherent in the measuring device. Jc3s5h (talk) 20:32, 6 October 2011 (UTC)[reply]
ec Because those models have been simplified. At some point, the oscillation in a damped system will be below that of molecule vibration. For all intents and purposes, it is no longer oscillating, but in the mathematical model, you can say it is still oscillating even if it is only moving 1x10^-50 m per cycle. Googlemeister (talk) 20:33, 6 October 2011 (UTC)[reply]
I would say that the most general explanation falls under the description of stick-slip motion. While the surface-mechanics are still an active area of material science research, stick-slip motion is a very well known model of real-world friction behavior. Basically, what it means is, below a certain velocity, the friction becomes much larger and the object "sticks." We have lots of mathematical models to approximate such behavior: various empirical hysteresis curves can be fit to approximate motion.
Is the gulf stream or north atlantic drift really moving southwards if so what is causing this. Would the mid atlantic ridge eventually have an impact the gulf stream and north atlantic drift therefore changing the climates of different regions. — Preceding unsigned comment added by 86.41.89.65 (talk) 20:52, 6 October 2011 (UTC)[reply]
I'm looking at T1 and T2 relaxation times in physics labs ... and being experienced in chemical NMR I am rather puzzled over many aspects of NMR that I overlooked. The pathetic strength of the magnetic field we're using means that we have to use 21 MHz signals (rather than say 300 MHz signals) though. For one, though resonance frequency differences between protons in different chemical environments can't really be resolved that well (though we can pick up differences that are sometimes on the order of parts per ten thousand as opposed to million). The other thing is that differences in relaxation times can be very dramatic.
Why would T1 of glycerol (T1 seems to be ~20 ms) be much shorter compared to the T1 of isopropanol and water (both are >1000 ms)? I get the idea that more oily or more solid implies a shorter T1 -- but is glycerol really that much different from ethanol chemically? Why would this be so? And how would chemical properties (solvent effects, chemical activities, densities and so forth) theoretically affect T2?
It surely can't be that simple. Water must surely have a stronger and more robust hydrogen-bond network than glycerol. For one, it can pack a lot more hydrogen bonds into a given space. Furthermore, this trend doesn't necessarily hold with other polyols. Furthermore, many viscous liquids aren't even polar. elle vécut heureuseà jamais (be free) 01:48, 7 October 2011 (UTC)[reply]
I don't know the answer to this one. The real question is, how do you predict viscosity (in general) from first principles? I found an abstract [44] which says "So in this work, a virial equation for calculating the viscosity of dense liquid was introduced according to correlating the dimensionless residual viscosity and reduced density. Adopting critical parameter (Tc, Pc), molecular mass (M) and accentric factor (ω) as parameters, the calculation can be accomplished. So the calculation of the viscosity of dense liquid is consistent with the calculation of equilibrium properties perfectly over the entire fluid range." This person has a site here but I couldn't get in. Wnt (talk) 03:09, 7 October 2011 (UTC)[reply]
Also in general, what would differ between glycerol and isopropanol (there are both organic alcohols) that would make for very long T1 and T2 relaxation times for isopropanol compared to glycerol? Why would spin-spin relaxation times be affected? elle vécut heureuseà jamais (be free) 05:11, 7 October 2011 (UTC)[reply]
I can't answer this one. I don't even understand how spin echo can be consistent with what I thought would be the quantization of the nuclear spin each moment is being measured. And I'm not entirely clear on what is being transferred to where with T1 and T2 of these materials. It would be kind if you'd humor me with a description of what you know about this system ... I really hope someone answers your question! Wnt (talk) 17:09, 7 October 2011 (UTC)[reply]
Is there software that can animate chemical reactions?
I would like to be able to set up a reaction and be able to watch it in 2D or 3D, for instance in the reaction CO2 + C > 2 CO I'd like to see the O atom breaking from the first C and then attaching to the second C. I know Chemsketch can animate a molecule, but something that did a reaction would be awesome. Does anything like this exist? NoformationTalk23:17, 6 October 2011 (UTC)[reply]
Plasmic Physics is way off. Such methods of animating simple chemical reactions have existed for decades. Here is an abstract from J. Chem. Ed. from 1995 which discusses how to animate such chemical reactions. I can also find any of several dozen more recent articles from J. Chem. Ed. which discuss the use of computer animations in a wide variety of applications. Many of these are simple animations of "ball and stick" or "space-filling" models transfering balls from one molecule to another, but trivially one could show electron flows between molecular orbitals (i.e. between HOMO and LUMO orbitals) that show bonds breaking and forming in simple computer animations, which would match expected mechanisms of such reactions. Like say this video which involves a reaction even more complicated than the one the OP came up with. --Jayron3204:19, 7 October 2011 (UTC)[reply]
While there is software that can animate *some* chemical reactions, there is no software that can accurately animate an arbitrary chemical reaction. Because, as Plasmic Physics points out, there's no way to predict a priori how a particular chemical reaction proceeds. You can have a theory, or make analogies to other chemical reactions, but you have to actually do experiments to find out. Even then it can be hard to figure out and contentious. If your reaction is of a class that's been extensively studied (e.g. SN2, E1, etc.) a program may be able to make a guess of how the reaction goes, but the literature is filled with reactions which look like SN2 (or E1, etc.) reactions, but were later found to use some other mechanism. If all you have is a list of substrates, a list of products, and a set of reaction conditions, no software in the world will be able to give you an accurate animation, unless someone has already done the lab studies. For example, in the CO2 + C > 2 CO case: yes, a C=O bond needs to be broken and the C needs to form a bond with the O, but how does that happen? Is it dissociative, associative, or coordinated? (What happens first, the old bond breaking, the new bond forming, or do they happen at the same time? The transition state might not be 50%/50%, but something like 20%/30% or 60%/55%.) Is it an end-on attack, or does the new carbon form a three member ring across the C=O bond? (Because the latter is how some halogens add to double bonds.) Additionally, you likely don't have monoatomic carbon - it'll be in some sort of particle, so how does surface effects contribute to the reaction mechanism? - You can animate the reaction any way you like, but you can also draw pentavalent carbons. That doesn't mean that's what happens in the lab. -- 174.24.217.108 (talk) 16:52, 7 October 2011 (UTC)[reply]
All very true, but it wasn't readily clear if the OP wanted animations for software which animated known mechanisms, or predicted mechanisms. I read the question as the first; rather than the second. So it's OK. You can be correct too. I don't mind that much. It really doesn't bother me that you are correct. --Jayron3218:32, 7 October 2011 (UTC)[reply]
October 7
Largest arthropods: land versus sea
See Largest organisms#Arthropods (Arthropoda). It appears to me that the largest arthropods on land are significantly smaller than the largest under-water arthropods. Is this correct? If so, why? Does it have to do with the ability of the exoskeleton to support its weight or access to oxygen or control of water content or vulnerability to predation or what? More generally, what limits the size of arthropods? JRSpriggs (talk) 03:48, 7 October 2011 (UTC)[reply]
For mammals as well, the largest mammal in the sea (the Blue Whale) is orders of magnitude larger than the largest mammal on land (the elephant). The reason for this is buoyancy, and I suspect that for arthropods, the reasoning is similar. --Jayron3204:04, 7 October 2011 (UTC)[reply]
Do you mean that buoyancy reduces the weight of the animal relative to what it would weigh on land? And wouldn't there be another factor in that the ocean is more vast both in surface area but perhaps more importantly in the depth that it offers? Bus stop (talk) 04:15, 7 October 2011 (UTC)[reply]
Animals on land are limited in size because beyond a certain limit, they would not be able to support their own weight. Animals in the water are bouyed by the water, which allows for larger animals to exist in the water. --Jayron3204:23, 7 October 2011 (UTC)[reply]
Perhaps nothing illustrates this more clearly then Siphonophorae, some of which can reach 40m-50m in water, but would obviously resemble little more then puddles of goo on dry land. Vespine (talk) 05:45, 7 October 2011 (UTC)[reply]
The size of the largest aquatic and land-living arthropods, does not differ that much. The largest ever aquatic arthropod is the Devonian eurypterid Jaekelopterus rhenaniae (8.2 ft). The largest ever land arthropod is the Upper Carboniferous myriapod Arthropleura (8.5 ft). The largest extant arthropod by mass is the American lobster Homarus americanus (3.5 ft). The largest living land arthropod is the coconut crab Birgus latro (3.3 ft). The Japanese spider crab may be considered larger by some, but only because it has amazingly long spindly legs. However, it is true that land arthropods are smaller than aquatic arthropods on average. And yes, you're probably correct on all counts (though the oxygen factor as a limit is still contentious):
Gravity - exoskeletons cover the exterior of an animal and thus are much heavier than animals with endoskeletons like vertebrates in proportion to size. Proportionally, a smaller arthropod will require a thinner exoskeleton than a larger arthropod to maintain rigidity and motion. Water provides a buoyant support for large aquatic animals. Land animals, however, have to depend on the rigidity of their supports. And in order for exoskeletons to be more rigid it needs to be exponentially thicker and heavier the larger the animal is. There is a point where it becomes mechanically impossible to increase any further (a gravity limit). In addition, exoskeletons need to be molted, they can not grow continuously like endoskeletons. A molting giant arthropod on land would collapse into a squishy mess under its own weight, resulting in deformities when the exoskeleton hardens. Add to this the fact that when molting they are extremely vulnerable (they can't even move as the exoskeletons are the supports for their muscles like our bones are).
Oxygen - arthropods don't breath with lungs but by direct surface absorption into a network of tracheae. Although crustaceans and arachnids do have gills and book lungs, they also have far more primitive circulatory systems than vertebrates. Tracheal respiration are passive systems. The larger the size of an animal or the thicker the exoskeleton, the harder it is to get oxygen into the deeper internal organs. This is proposed to have been why the hyperoxic conditions of the Carboniferous resulted in land arthropods reaching gigantic sizes. Add to this the problems of water balance. Aquatic arthropods do not have to worry about leaks or evaporation.
Predation - Paleozoic land arthropods (and aquatic arthropods a little further back) reached very large sizes due to the lack of competition (compare eurypterids which arose before fish and Carboniferous land arthropods which arose before land vertebrate dominance). As vertebrates started taking over some niches, it became too risky for them to increase in size. Per previous reasons, the larger they are, the weaker they are relatively in comparison to animals with endoskeletons. A flea can jump ~200 times its body length, increase their size, and that proportionally becomes much lower.-- Obsidi♠nSoul08:20, 7 October 2011 (UTC)[reply]
I should note that as mentioned in Invertebrate trachea, some insects have air sacs at the end of the tracheae, and air can be forced into and out of the system. However, while arthropods ordinarily should be well capable of using muscular movements to suck in air via the tracheae, during molting the situation is different - those movements shouldn't work, but land arthropods take in air by swallowing it.[45] For small arthropods, I assume the air in the stomach provides a source of oxygen (besides, it takes a long, long time to suffocate an arthropod...) - still, it sounds like a problem. But I don't see why very large insects couldn't evolve some method to permit air to leak into the tracheal system or otherwise to distribute itself from the foregut during that time. Wnt (talk) 11:19, 7 October 2011 (UTC)[reply]
Tracheal breathing in bees, grasshoppers, and dragonflies, etc. are actually still heavily mechanical. They only function when the insects are not at rest (e.g. flying, when the metabolic demands are the highest, or when in an alerted state). The rest of the time, it breathes through diffusion. And they did. That's why the largest arthropods today are crustaceans and chelicerates. Because their larger members have gills, branchiostegal lungs, book lungs etc. which do not rely on passive diffusion, and they have blood that can carry oxygen (hemocyanin). But as mentioned, their hearts are still relatively far weaker than vertebrate hearts.-- Obsidi♠nSoul14:12, 7 October 2011 (UTC)[reply]
e/c: Also no. They can not breathe swallowed air. And I'm curious where you got the 'they take a long time to suffocate' bit. Instances of seemingly long suffocation times are merely the result of them still getting oxygen through cutaneous respiration from what would have drowned a vertebrate lung. See [46] -- Obsidi♠nSoul14:49, 7 October 2011 (UTC)[reply]
Well, you can "anesthetize" a caterpillar for purposes of macabre manipulation by keeping it under cold water - given the low metabolic rate, further reduced by the cold, they can survive around an hour that way. This is true even though some effort is made to exclude large external air bubbles, though of course small ones remain.
I would be very surprised if no oxygen makes it out of the stomach, when so much is swallowed that it distends the entire insect. Wnt (talk) 17:01, 7 October 2011 (UTC)[reply]
You mention that the lobster and the coconut crab have roughly the same length, but the lobster is more then 4x heavier. I do not see the weights for the prehistoric examples you mention, but the aquatic one looks like it would also have significantly more bulk. Googlemeister (talk) 14:22, 7 October 2011 (UTC)[reply]
Probably, though both Arthropleura and Jaekelopterus were dorsoventrally flattened, unlike coconut crabs and lobsters. Also note that some eurypterids may have been amphibious, some of the first animals to set foot on land, really. They are actually the direct ancestors of modern land scorpions and spiders.-- Obsidi♠nSoul14:49, 7 October 2011 (UTC)[reply]
Where could I find data on what percentage of Filipinos carry a blue allele for OCA2? I once knew a guy with bright blue eyes whose parents were both Filipinos with brown eyes and it struck me as pretty uncommon. His sister had brown eyes like their parents. 20.137.18.53 (talk) 13:38, 7 October 2011 (UTC)[reply]
That's probably just a result of mixed ancestry? Some "full Filipinos" tend to not be fully Austronesian. One of my grandfathers had blue-gray eyes (more gray than blue), and one of his sons (my uncle) had gray-greenish brown eyes. But our ancestry is very mixed. And yes, this is very uncommon. -- Obsidi♠nSoul15:29, 7 October 2011 (UTC)[reply]
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