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July 4

New Madrid earthquake damage zone

Red represents severe damage, and yellow lesser damage

What geological factors (aside from the horizontal extent and severity of a fault, of course) influence the amount of surface (mi², km²) that is affected by an earthquake with its epicenter at a given location? In this case, I'm wondering why a 6.8 earthquake at New Madrid would cause heavy damage as far east as eastern Ohio while causing lesser damage in much of southeastern Missouri — not to mention the far tinier area damaged by a Los Angeles earthquake of slightly lesser strength. Nyttend (talk) 04:40, 4 July 2016 (UTC)[reply]

Well for one, I believe this is a map of structural damage. The New Madrid earthquake took place when there were no seismic codes, while the Northridge quake took place in an area with very good seismic codes. Besides that, soil type and terrain will play a role. Different types of ground transmit seismic waves differently. The Los Angeles area is basically a bunch of mountain valleys bunched up against the sea, so the mountain terrain will attenuate seismic waves. And the depth of the hypocenter will influence how far the waves travel. --71.110.8.102 (talk) 06:12, 4 July 2016 (UTC)[reply]

To back that up with an anecdotal note, I lived through the Northridge quake, in the same home I'm sitting in right now in Riverside County. All we got was a good few jolts. There was no real structural damage in the area. --71.110.8.102 (talk) 06:20, 4 July 2016 (UTC)[reply]

Here is a Wayback Machine copy of the page the image was taken from. Red indicates "minor to major damage to buildings and their contents", which might be affected by building codes, but yellow indicates "shaking felt, but little or no damage to objects, such as dishes" and so its outer boundary will not be affected by building codes. (I'll add those explanations to the image's description page.) The page states that "Earthquakes in the central or eastern United States affect much larger areas than earthquakes of similar magnitude in the western United States", but says nothing about why. --69.159.60.163 (talk) 03:45, 5 July 2016 (UTC)[reply]

Well, you might as well look at the Virginia 2011 earthquake which was felt from Canada to the southern coast. It was not such a large temblor absolutely, but the crust of the eastern US is very cold, hence solid, hence a good transmittor of what in California wouuld be small, local quakes. μηδείς (talk) 17:48, 4 July 2016 (UTC)[reply]

We're talking about 'Q' anelastic attenuation factor (or strictly its inverse), the degree to which rocks absorb seismic energy. The rocks of the Laurentian shield have generally high Q and therefore seismic waves are not attenuated quickly. California is a lot more heterogeneous and has a generally much lower Q value. This paper (Figure 11) compares the variation of Q with frequency for different parts of the continental US. The maps of yellow and red by the way are isoseismal maps. Mikenorton (talk) 22:40, 5 July 2016 (UTC)[reply]

Finasteride and anabolic steroids

Request for Medical Advice

The following discussion has been closed. Please do not modify it.

If a person is taking finasteride 1 mg for male pattern baldness and uses steroids for bodybuilding then does finasteride withstand the huge surge of testosterone? — Preceding unsigned comment added by 182.18.177.78 (talk) 10:38, 4 July 2016 (UTC)[reply]

This is a biology question, not a medical advice question. The biology is pretty interesting - testosterone is converted to the more androgenic dihydrotestosterone by 5-alpha reductase. It is that last thing, an enzyme, that finasteride actually blocks - the drug is not actually an antagonist of testosterone like cyproterone acetate. That means that some anabolic steroids - our article lists mesterolone (1α-methyl-DHT) and drostanolone (2α-methyl-DHT) - are analogues of the DHT that is already past the gate finasteride is supposed to guard, and it will have zero effect on them. (Then again, I don't know that, because biology could throw some crazy curve ball, reacting to the change in testosterone level in some other way!) Other anabolic steroids, like testosterone, still may interact with finasteride, though honestly I have not done the research needed to see if the enzyme is already converting as much testosterone as it can so that no more can effect it. Either way, by and large, I expect the large doses and strange forms of steroids will make finasteride pretty irrelevant at stopping their anabolic effects. Now on the other hand, what about the hair loss? Well, honestly, I haven't looked it up. Every artificial steroid has its own chance potentially to interact differently with receptors in the cell, and so while it would seem a good guess that muscle-building and hair-loss effects are in lockstep, I'd have to see empirical evidence to believe it. And who is going to round up a bunch of balding men to give them dangerous steroids to see if they lose all their hair in a hurry? Unless I land a job at a POW camp for a very long war, I'm expecting not to figure this one out, though it's possible there's some wince-worthy study buried in the literature. Wnt (talk) 20:38, 4 July 2016 (UTC)[reply]

Suggestions for excess solar energy

Hi I have a 5kW solar solution (with 20 panels) but my average usage during the day is about 1.5kW. At night I connect to the grid but have a battery backup if the grid goes down. Originally I was told that excess energy could in future be fed back into the grid, but this is not yet supported in my country by the national energy regulator. In the mean time I would like to make use of all this excess energy and recover some of the costs of this hugely expensive solar investment. Given that I have on average about 2.5kw to 3kW to spare during the day (taking into account losses like shading, time of day and irradiation seasonal differences) - can you guys come up with some ideas to make some recovery money off this? I would be open to an additional smaller investment if necessary. Thank you. Sandman1142 (talk) 11:29, 4 July 2016 (UTC)[reply]

Could you increase your consumption of electricity? Do you heat and cook with electricity already? Do you have any electrical vehicle? --Hofhof (talk) 12:11, 4 July 2016 (UTC)[reply]

Oh I forgot to mention I use gas for cooking (low gas usage) and water heating (high gas usage). This was chosen 5 years before deciding on solar. No electric car. Makes sense to do the water heating with solar but I had already invested a lot of money in the gas connection and Rinnai heater which works very well. Sandman1142 (talk) 12:40, 4 July 2016 (UTC)[reply]

Get a multicooker and a microwave, which are inexpensive and useful.
You can save fuel and environment, preheatung the coolant of the combustion engine in the car and charge the battery. Cold start and cold run require increased fuel consumption. Higher valued vehilces built for use in Canada, Alaska, Siberia, Scandinavia and Iceland are equipped with it, but the savings might be not that high. It requieres an electric coolant pump. Anyway in Winter, then not too early for sun rise, You would not have the need to scrap the ice from the windshield. But it would require expensive batteries, to store the electricity over night for the next morning. Also the lifetime of batteries is limited.
If You can, have the freezer of the refirgerator going lower to save the bought electricity over night. Never use washing machine, dryer and dishwasher over night, just pre wash, if neccessary.
A geothermal heat pump will exceed the power of Your solar panels, but if You own a air condition which is designed to use the its heat pump in reverse for heating the room, it might heat up to double efficient than a conventional heating resistor. Some air conditions only have a conventional heater installed. There are no further savings on energy. But if the air condition is able to operate the pump by switching radiator and condensor each other, it just cools the atmosphere outside and pumps the heat into the room, saving energy compared to a conventional heater.
Power to gas units are not avail in a 5 kWh range and do not work efficient, but produce gas from water and electric energy. Often the units produce hydrogen only, but methane is requried for the gas grid. Gasoline cars can be modified to switch to a propane and buthane mix in ratios of 40/60% and 60/40% when the cold run finished, only. The 40/60 ratios are swapped by summer/winter season, due any engine damage. The engine needs to startup with gasoline.

In Germany the electic companies are required by law to buy up to 10 kWh per customer. --Hans Haase (有问题吗) 14:26, 4 July 2016 (UTC)[reply]

You could join distributed computing projects. See List of distributed computing projects. You get a chance of making a discovery (many such discoverers are mentioned in Wikipedia) or contributing to a shared effort. I don't know whether any projects offer payment apart from a tiny prize chance in Great Internet Mersenne Prime Search (GIMPS).[2] If you pay for electricity then the cost is many times larger than the expected prize money. PrimeHunter (talk) 15:01, 4 July 2016 (UTC)[reply]

Mining of bitcoin which requires a sizeable investment in computing hardware to perform "proof of work" is a way to convert surplus electric power to an income in Cryptocurrency. AllBestFaith (talk) 16:02, 4 July 2016 (UTC)[reply]

What a coincidence you should say this! I literally 10 minutes ago listened to the NPR podcast Planet Money which was talking about bitcoin mining. It also talks about the main issue in bitcoins right now - the fact that bitcoins aren't transferring.[3]

Whoever gets a good solution to this should move to Germany and get rich. This is becoming a serious problem in Germany, a country with lots of solar, where the grid sees inverse spikes when the sun pops from behind a cloud.

For South Africa, can you look at cold banking? Producing cold during excess capacity and making use of that through an aircon system? All of these solar energy storage systems are needing to develop as local solutions for local climates. What's right for Spain or Germany isn't necessarily the right thing for South Africa. Andy Dingley (talk) 11:30, 5 July 2016 (UTC)[reply]

Thanks everyone for the replies. Producing cold or extra heat is a bit of a conundrum, because we are typically at work during the peak solar periods. We will only need the aircon or water heating or oven when are back home and that is around sunset or after. Bitcoin mining is interesting but I believe you need some serious hardware just to get a chance of solving one; a normal PC will not cope. I am considering an electrical water heater on the other side of house and then running the gas heater on the original side. Do you call these things geysers too? Wish I lived in Germany but here in Africa things move sloooowly. I was also considering running some sort of high energy manufacturing machines in my garage during the day... Sandman1142 (talk) 11:46, 5 July 2016 (UTC)[reply]

Sandman1142, before You think Germany is a paradise. No, Germany is a paradise for crimal people. Heating up water is not efficient with electric solar, only. Solar cells convert less than 20 % electric power for the light input. Thermal solar collectors can preheat the water, sometimes hot enough, else reaching the needed temperature can be done by gas or electric. Prices for electric energy have increased in Germany, but are still cheap. Never the less several thousands were cut form electricity due unable to pay the bill. Gasoline is expensive, diesel is taxed lower. Never the less in Germany, false information is spread about automotive technic, especially about hybrid vehicles. One of the suggested lies is, Plug-in hybrid vehicles were unable to drive when batteries could not be charged from the grid. The truth is, charging the battery is cheap, but the vehicle gernerates its own electric power from a generator and convert the brake power. In the US, rumors about "free energy" are spread arround. While a policical decission ruined most of the German solar industry, now the Chinese do a good job. Wikipedia has no article about. It is not mentioned in 2011 in Germany#Renewable energy and Solar power in Germany, but still have a vision about Desertec. --Hans Haase (有问题吗) 00:39, 6 July 2016 (UTC)[reply]

UV incidence

What's the difference between UV incidence in the shadow and direct exposure to the sun? For example, if you are in a street and one side is sunny while the other is shadowy. How much would the UV rays bounce to the shadow?--Hofhof (talk) 11:58, 4 July 2016 (UTC)[reply]

Visible light can be measured in units of lux; have a a look at radiometry to review all the different ways we can measure "amount of light." For ultraviolet light, we typically prefer to use a different unit. (Are we counting photons? Watts? Integrating watts over wavelengths? Estimating perceptual brightness to the human eye? Using some type of dosimetry to estimate health impact? ... and so forth). The original question was phrased in terms of "incidence" - so we might reasonably assume that we want to use Illuminance ... but because we're talking about the UV spectrum, there is definitionally zero ultraviolet illuminance in the sun and in the shade! The standard unit only measures visible light. This makes sense - your human eye sees the exact same amount of ultraviolet light whether you stand in the sun or in the shade - and that's what "incidence" measures in the SI system of units.

In the visible spectrum, our article on lux § illuminance estimates anywhere from 10 to 100 times more light - in units of lux - in direct sunlight than in shade. It is reasonable to assume approximately the same ratio between direct sun and shade for invisible near-ultra-violet light; it won't be exactly the same, because various materials and surfaces reflect and disperse UV and visible light differently - but it's a good ballpark estimate. More to the point, we rarely use lux for the ultraviolet portion of the spectrum - these special units of measurement only correctly apply to the visible spectrum of light. If you want more precise measures, it will help to start by refining the search based on how you want to measure the amount of ultraviolet light. In other words, which type of unit are you looking for?

For the scientifically inclined reader: this website - the personal website of one Pat Arnott, a professor, researcher, and enthusiast of satellite remote-sensing, hosts a 1987 JGR publication on the reflectivity and transmittivity properties of Earth's atmosphere in the ultraviolet spectrum. That'll probably give you all the math you need to completely constrain the incident power in most parts of the Ultraviolet spectrum, on Earth, in various weather conditions. You might not even want to answer your original question unless you're the kind of person who finds this type of sentence attractive: "the directional albedo A of a Rayleigh scattering atmosphere of optical depth τ bounded by an opaque lambertian surface of reflectivity R is given by... (massive equation)."

Nimur (talk) 12:50, 4 July 2016 (UTC)[reply]

Here's another source, from a dosimetry standpoint: Penetration of solar erythemal UV radiation in the shade of two common Australian trees. (1999). That source indicates that UV dosage, as pertaining to its health effects on human skin, measured in the shade provided under a tree was 37% to 55% of the dosage in direct sunlight. Here's a more recent review article, Human exposure to solar ultraviolet radiation (2001). Both articles provide lots of additional citations. Nimur (talk) 15:33, 4 July 2016 (UTC)[reply]

The article Ultraviolet photography provides a link to these ultraviolet street scenes. Images photographed in ultraviolet light must be presented in a false monochrome or colours. AllBestFaith (talk) 15:48, 4 July 2016 (UTC)[reply]

Rayleigh scattering preferentially affects shorter wavelengths, so that diffuse light (which is what makes it into shadows) is relatively enriched in UV. An interesting article is available here. Shock Brigade Harvester Boris (talk) 03:51, 5 July 2016 (UTC)[reply]

The die is cast

Until reading out article on alea iacta est, I assumed that "die" referred to a Die (manufacturing) after the process of casting, when it's too late to make another design, not to half of a pair of dice that had been thrown. Was the use of metal dies (in any form, regardless of how primitive) known to the Romans in Cæsar's day? The article has no history of dies, and it's really hard to run a search when the term "die" is so commonly used for other concepts. Nyttend (talk) 13:21, 4 July 2016 (UTC)[reply]

The way I learned the history of technology, machine tools - and specifically, the use of metal die tooling - are an amazingly new invention, circa 1800 AD - in the earliest days of the steam-engine. Earlier metalworking used forging, casting, brazing, but never punching or tooling. It's hard to specifically cite the non-existence of older machine tools... but that's how I've always seen things laid out in history museums. For example, the British Science Museum has an excellent collection of industrial tools and there is a marked transition in their exhibit on steam power, where the first metal machine tools are found. Episode #5 of Series One of James Burke's Connections described the connection between the rifle, the cotton gin, and subsequent invention of machine tools and dies in the 1790s.

It might be worthwhile to find a good dictionary and review the etymologies for the word "die" - there's surely some significant information buried in the fact that the Latin word is not like our word, but I'm not enough of a linguist to interpret that signal.

Nimur (talk) 13:40, 4 July 2016 (UTC)[reply]

According to the Oxford English Dictionary, the source of English "die" is surprisingly the Latin "datum" meaning "given". They say "it is inferred that, in late popular Latin, datum was taken in the sense 'that which is given or decreed (sc. by lot or fortune)', and was so applied to the dice by which this was determined." The meaning "an engraved stamp used for impressing a design upon some softer material" is first attested in 1699 although there's no indication of how this transfer of sense occurred. According to Wiktionary [4], the Latin "alea" originally meant "pivot-bone or joint-bone, since bones were used for early dice" and derives from "axis". CodeTalker (talk) 14:44, 4 July 2016 (UTC)[reply]

The article linked above is pretty clear, tracing the phrase back to a Greek phrase in which the key word is κύβος, which is to say, a "cube" or six-sided die. Wnt (talk) 20:14, 4 July 2016 (UTC)[reply]

Hammered coinage claims the earliest coins (first millennium BC) were made by hammering on a planchet placed between two dies. No clue where the word comes from, however. Thincat (talk) 21:09, 4 July 2016 (UTC)[reply]

That's factually accurate, but the words you are using, such as "coin" are very recent, not Greek or Latin. Originally, knuckle bones were used as dice. μηδείς (talk) 22:29, 7 July 2016 (UTC)[reply]

Why are thorium and uranium so stable?

²³²Th and ²³⁸U have half-lives of billions of years, while everything else in that region decays away in at most millions (²³⁵U, ²³⁶U, ²³⁷Np, ²⁴⁴Pu, ²⁴⁷Cm), and most likely not even that. I assume there is a nuclear shell closure going on here, but where can I find a less vague, more detailed explanation? Double sharp (talk) 14:52, 4 July 2016 (UTC)[reply]

Stable nuclide. AllBestFaith (talk) 15:30, 4 July 2016 (UTC)[reply]

I'm well aware of that article, but thorium and uranium are not actually absolutely stable like the nuclides discussed there are. They are, on the other hand, relatively much more stable than the neighbouring elements, and my question was why they decay as slowly as they do. Double sharp (talk) 15:37, 4 July 2016 (UTC)[reply]

Because they are within one of islands of stability. Ruslik_Zero 16:18, 4 July 2016 (UTC)[reply]

As far as I am aware, la Isla de estabilidad is an award-winning novel by Umberto Eco. Its existence is more expected than it is an explanation. μηδείς (talk) 17:22, 4 July 2016 (UTC)[reply]

Are you talking about L'isola del giorno prima? --Trovatore (talk) 23:08, 7 July 2016 (UTC) [reply]

The article has a bare-bones explanation:

The hypothesis is based upon the nuclear shell model, which implies that the atomic nucleus is built up in "shells" in a manner similar to the structure of the much larger electron shells in atoms. In both cases, shells are just groups of quantum energy levels that are relatively close to each other. Energy levels from quantum states in two different shells will be separated by a relatively large energy gap. So when the number of neutrons and protons completely fills the energy levels of a given shell in the nucleus, the binding energy per nucleon will reach a local maximum and thus that particular configuration will have a longer lifetime than nearby isotopes that do not possess filled shells.

Of course it's far from a complete explanation, more of a starting point. Presumably you can use the references in the article and follow the thread as far as the state of human knowledge currently allows. --Trovatore (talk) 20:23, 4 July 2016 (UTC)[reply]

A very accurate universal decay law was recently discovered, see here for details. Count Iblis (talk) 22:03, 4 July 2016 (UTC)[reply]

If only it were written in ENGLISH! Otherwise, it seems cool, but it's tooo effin'ard to understand. μηδείς (talk) 02:55, 5 July 2016 (UTC)[reply]

This book https://www.amazon.com/Elements-Their-Origin-Abundance-Distribution/dp/019855298X goes into the nuclear shell theory, it is most certainly among the 10 most brilliantly written and edifying books I have ever read. μηδείς (talk) 22:54, 7 July 2016 (UTC)[reply]

July 5

Smelly hot water

I recently stayed in a private home in Vilnius, Lithuania. The home appeared to be recent construction (< 5 years old, is my guess, but I didn't ask). The cold water appeared normal, but the hot water carried a strong odor that resembled bad eggs. We were told that this had something to do with the builder using the wrong type of pipes to carry hot water. Being Lithuania, we weren't drinking the water at all (bottled water only), though we did use the water for showering / cleaning, as the people who lived there recommended. Can anyone make an educated guess of what kind of pipes react with hot water to give a strong odor? Is this likely to be H2S, or something else? Both the hot and cold water appeared clear. Dragons flight (talk) 07:42, 5 July 2016 (UTC)[reply]

It is doubtful that the metal or plastic of the pipes is caused the smell. Look at this and this, they both seem to think it is something to do with some sort of (?harmless) anaerobic bacteria that react with the anodes in the heating system and make hydrogen sulphide which causes the odour. Richard Avery (talk) 11:04, 5 July 2016 (UTC)[reply]

It's usually a combination of several things. Gypsum in the local geology leads to sulphur in the supply water, then a steel water heater is used, which requires a magnesium sacrificial anode. These encourage anaerobic bacteria to develop which produce hydrogen sulphide you can smell.

It's hard to eradicate this, especially in showers. Hydrogen sulphide can be smelled at very low concentrations (1 or 2 parts per million) and standing in an aerosol of water droplets gives a large surface area to release the dissolved gas from the water. Chlorinated water supplies tend to stop it - but you might then smell the chlorine. A regular drain, clean and bleach treatment for the water heater can be useful in bad cases. This is often needed for properties only used intermittently. Controlling the water heater temperature can help too, and also helps against Legionella. Some makers sell non-bacteriogenic anodes. The traditional British alternative was copper water heaters which didn't need anodes. Germany uses modern stainless or plastic water heaters. A modern solution is to avoid a large-volume stored water heater in favour of low-volume, high-power on-demand "instant" water heating. That's usually the simplest option, if the electricity supply permits it. Andy Dingley (talk) 11:26, 5 July 2016 (UTC)[reply]

We have a garden hose, that when left in the sunlight, produces what smells like swamp water, even though we started with nice chlorinated water. So, you're not alone. StuRat (talk) 00:52, 8 July 2016 (UTC)[reply]

Artist renditions of spacecraft instead of photos

I noticed that many, if not the majority of our articles on spacecraft, most recently Juno uses artist renditions of them rather than actual photos. Isn't it easy for NASA or ESA to make a photo and release it under the same free license they publish artist renditions? Brandmeister^talk 09:07, 5 July 2016 (UTC)[reply]

I don't think anyone would see it with all panels attached and unfurled like that. -- Q Chris (talk) 10:35, 5 July 2016 (UTC)[reply]

The drawings usually show them in space with a planet, moon, asteroid or at least stars in the background. That was also the case in your example where the transparent version was made at Commons. I have displayed both versions here. PrimeHunter (talk) 10:47, 5 July 2016 (UTC)[reply]

In June of this year, I received a ticket to explore JPL, and we got to tour High Bay 1 (the clean-room where Juno was assembled and packed for transport to its launch facility). The clean-room is one of the largest in its class, world-wide - and even still, it would be very difficult to fully assemble the Juno orbiter in its deployed, space-flight configuration. Furthermore, the space-craft is structurally designed for operation in microgravity - it surely is not sturdy enough to hold its own weight with its solar panels deployed in Earth gravity. For demonstration-purposes, an engineering mechanical mock-up of one of Juno's solar panel arrays was fully extended and mounted on a display platform - and the panels are very large compared to the room.

I'll try to find a good photograph from that tour and upload it to an appropriate article. It helps demonstrate why it is difficult to photograph a fully-assembled spacecraft. It may also help to remember that the clean-room is not a photo studio: it is a shared resource for all of NASA JPL. As a one-of-a-kind, world-class, operational engineering facility, its special capabilities must be in continual use to prepare other missions in the multi-year pipeline that is the work of building spacecraft! There's not a lot of "free space" to put together a photo-shoot.

Once in orbit - the spacecraft is usually far away from any person or robot who might take a photograph of it! Sometimes, cameras can be mounted on launch vehicles, or on separated stages, and so forth - but for the most part, the only available cameras are the scientific experiment packages mounted on the spacecraft, pointing away from the spacecraft! Except in very rare cases - like a few of the recent Mars landers - those kinds of science payload cameras can't be pointed or moved at all, so they're totally unable to "take a selfie" of the orbiter platform. For a good conceptual exercise, the next time you ride on a commercial airline flight, think about trying to photograph the airplane, from the outside, while it's flying - and you'll have a greater understanding of how very difficult it would be to get that photo! You can't simply pop open the door and walk onto the wing - and even if you could, you still wouldn't be able to frame the wing in your picture!

Nimur (talk) 14:28, 5 July 2016 (UTC)[reply]

Sure you could. Just wait a couple tenths of a second... Wnt (talk) 15:41, 5 July 2016 (UTC)[reply]

Launch of the Hubble Space Telescope was delayed from 1986 to 1990 due to the Challenger disaster. During that time, it was stored in a nitrogen atmosphere clean room in Silicon Valley. I had the chance to see it during that time through a window. It was impressive but seeing it operational in orbit is another thing entirely. Many in orbit photos are available since it has been serviced four times by astronauts, and it looks much more impressive in orbit than in a crowded clean room. On the other hand, there is no opportunity to take photos of operational deep space probes. Cullen³²⁸ Let's discuss it 07:39, 6 July 2016 (UTC)[reply]

The only recognisable photos of probes in deep space that I'm aware of are the pictures that Philae and Rosetta took of each other as they separated: photo 1, photo 2. These show another problem with trying to get pictures in space: you're not going to get anywhere near the quality you do on Earth (If you think those are bad, here's how Huygens looked pictured by Cassini). The cameras aren't designed for tracking a fast-moving, nearby object, especially one that's not well lit by sun. Plus, a spacecraft being a few metres across means that you need to be relatively close to it to get a decent photo (even the Lunar Reconnaissance Orbiter, our best Moon spacecraft, can barely make out the Apollo landing craft). Smurrayinchester 07:45, 7 July 2016 (UTC)[reply]

Bats eating mosquitoes

A headline in today's NYTimes reads: "Devouring 1,000 Mosquitoes an Hour, Bats Are Now Welcome Guests as Zika Fears Rise". A quick google search indeed suggests that this 1000/hr rate is widely quoted. That would be one mosquito every 2.7 seconds for an hour straight... I'm skeptical. It just doesn't pass the common sense test. I would like to be pointed to a credible scientific source confirming or repudiating such a claim. I reckon the NYTimes should be better than this, and maybe also the local officials in towns hoping to impact Zika by housing bats. It isn't hard to find seemingly authoritative sources suggesting that controlling mozzies with bats has not been proven as effective...thanks if you can shed any echolocation on this claim. — Preceding unsigned comment added by 94.210.130.103 (talk) 12:40, 5 July 2016 (UTC)[reply]

Wouldn't that be one every 3.6 seconds ? Also note that they could consume at the rate of 1000 per hour without actually eating for an hour. (If they eat 250 in 15 minutes, that's still the rate of 1000 per hour, even if they then stop.) StuRat (talk) 20:35, 5 July 2016 (UTC)[reply]

Note that the star-nosed mole can eat worms in less than a quarter second: [5]. In the case of bats, that speed may be based on the assumption that the mosquitoes are tightly packed, say near a swamp. StuRat (talk) 20:43, 5 July 2016 (UTC)[reply]

Yeah I strongly suspect this would be "when there's a swarm of mosquitos", I doubt they "chase and hunt" each mosquito one by one. Vespine (talk) 23:30, 5 July 2016 (UTC)[reply]

Yes, your math is way better to get to the one every 3.6 seconds. Thanks for that. But I think my question remains ... the headline and the story, and the many repetitions of the number and the claim - don't talk about 'at a rate of 1000 hour', over a short time - I can also kill one mosquito in 3.6 seconds - but my point, and my curiosity about finding any real research, is that even though I can kill a mosquito in 3.6 seconds by a method of slapping it with my hands, and maybe another in another 3.6 seconds in the right circumstances - I'm sure I wouldn't sustain the rate and be able to kill 1000 mosquitoes in an hour, and I'll be surprised if a bat can. The headline, story and other sources really talk about a bat eating as many as 1000 mosquitoes in an hour. The only time I don't like the ref desk is when a query specifies trying to find actual academic, scientific, or other referenced sources. In this case, speculating that in a swarm of mosquitoes, in a swamp, a bat might eat some mosquitoes at a rate pf one every 3.6 seconds for a while, which when you multiply that out means that they eat at a rate of 1000 an hour...and therefore local officials are encouraging bat boxes in urban neighborhoods to fight the Zika virus...the logic breaks down which is the point of my original question. — Preceding unsigned comment added by 94.210.130.103 (talk) 02:52, 6 July 2016 (UTC)[reply]

I would also be skeptical of the 1000 per hour claim, but that doesn't invalidate the argument that bats eat a lot of skeeters and that they are therefore a welcome addition to the battle against mosquito-borne diseases. OR here, but my Mom's house has bats, and mosquitoes are rare there, while my house does not, and I have lots of the buzzing bastards around. Also, bats are amazingly stealthy. All I ever see is the slightest flicker out of the corner of my eye in a shadow. No sound I can detect, and they stay hidden when I am around. They were a problem when they were living in my Mom's attic (and pooping there), but the bat houses would solve that. StuRat (talk) 03:33, 6 July 2016 (UTC)[reply]

Well.... I found ONE relevant study which actually states that most insectivorous bats DON'T eat a lot of mozzies. Of course saying that most don't does not exclude that a few DO. I've seen some interesting reading if you search for "bat diet mosquito" in google scholar, if you spent a couple of hours going through the results you could possibly find your answer. I suspect, but have not found where, the answer was derived from studying bat droppings which extrapolated or determined that in a 2 hour "feeding" period, a colony of 1000 bats ate 10kg of insects (10g each), of which 50% was mosquitoes. 5kg makes 2 million mosquitoes (at 2.5 milligrams each) , that's 2000 mosquitoes per bat, or 1000 per bat per hour. It would ALSO not surprise me if one step had been left out or left to assumption, like someone came up with total numbers and someone ELSE decided to count mosquitoes but forgot to count the moths out of the equation for example. So I do not consider this settled.. Vespine (talk) 05:31, 6 July 2016 (UTC)[reply]

This probably isn't an unbiased source [6] but some of the details could be followed up on. Interestingly they mention a fairly artificial study which estimated a consumption rate of 600 mosquitos per hour. While searching for info on the person (who I thought) did the study I found [7] which is mostly looking at the potential effect of mosquito control on bat populations. More interesting was [8] which quotes a 500-1000 per hour figure with [9] and [10]. Looking at the sources, the first one could be a decent study although it was in 1960, however as with the Tuttle study, it seems fairly artificial. The second one is interesting, but I'm not sure "With a bat detector and a stop watch, I have recorded as many as 20 catches per minute, which means that one bat may eat more than 1,000 mosquitoes in an hour!" should be counted as a particularly reliable measure. Going back to the PLOS study, it sounds like the 600 per hour figure from Tuttle wasn't actually from their own study but was simply mentioned in their book [11] and was based on the 1960 Griffin, et al. study. (Re-reading the first source, it doesn't actually say the experiment was conducted by Tuttle.) So the actual sourcing for consumption figures I could find don't seem particularly robust. Nil Einne (talk) 20:26, 7 July 2016 (UTC)[reply]

"Sparkler bomb"

I'm seeing some crazy stories [12] about a kid who supposedly taped 180 sparklers together and ended up blinding himself and a friend with metal fragments, blowing off the fingers of one hand, having part of a leg amputated, surgery on both arms, and leaving a "4 foot hole in the ground". Reading the article, apparently sparkler bomb really is a thing, with rare injuries of this type. But why do ordinary sparklers burn slowly and to all appearances safely, even when kids hold them clumped together in their hands, yet bump the number up an order of magnitude and they become an apparent high explosive? Or were these not ordinary sparklers? Wnt (talk) 15:39, 5 July 2016 (UTC)[reply]

From what the sparkler article says, a sparkler bomb is when you bundle a bunch of sparklers together and light them on fire. This will cause all the fuel in the sparklers to combust extremely rapidly. Combustion is a chemical reaction. The rate at which the reaction proceeds is affected by surface area. Light a single sparkler normally, and the reaction only proceeds at the tip. But if you ignite the whole thing, a lot more energy is released. This kind of thing is how you get dust explosions. See for instance what happens when you ignite a bunch of match heads all at once. Turns out explosives can be dangerous! This is why you have a bunch of people blowing their fingers off every Fourth of July here in the good old USA; they don't have a healthy respect for fire and explosives, and think fireworks are magic devices that just make cool lights and sounds, and can't possibly harm people or start fires. --71.110.8.102 (talk) 17:01, 5 July 2016 (UTC)[reply]

Hmmm, match heads are a weird case also. A safety match being struck, as far as I know, is essentially an application of Armstrong's mixture, one of the most notoriously user-hostile compositions in all of pyrotechnics. But it's true that without the striker they're just an oxidizer and fuel mixture, just as sparklers are. So I guess the mystery comes down to when sometimes fuel with oxidizer burns slowly, why some "combusts rapidly" and why some (like the Unabomber's aluminum powder fuel) is AFAIK truly a high explosive. It doesn't even depend on the chemical, come to think of it - charcoal in oxygen is a nice little fire, charcoal soaked in liquid oxygen is like dynamite. I guess a big part of it also is that we (or at least I) lack an intuitive sense for how much motion is hidden in a bit of heat - you work through calculations in joules and it just seems crazy. I guess nobody expects this, especially not kids playing with a big bundle of sparklers. Wnt (talk) 19:19, 5 July 2016 (UTC)[reply]

I suspect what you see in a sparkler bomb is chain reaction. Of course, a single sparkler also is a chain reaction, of a sort, in that the bit currently burning lights to next bit, etc. But the big difference is that with a single sparkler, most of the energy is dissipated into the air, while, if there are adjacent sparklers, the energy instead goes into lighting them, then their energy goes into lighting others, etc. Once they are all lit, the energy has no place to go other than further up the already lit sparklers, forcing them to burn faster. StuRat (talk) 20:30, 5 July 2016 (UTC)[reply]

I learned this lesson the hard way myself. I used to make home made blackpowder smoke bombs when I was a kid, you wrapped some of the black powder in a tissue and light it and it fizzles and spits and makes an enormous amount of smoke. One day I wrapped one up a bit too tightly with a bit too much tissue and instead of fizzling, it exploded. Fortunately it was only about a tablespoon worth and all I suffered from was a start and some burned eyebrows and a good helping of embarrassment because all my friends who were watching were rolling around on the floor laughing at me. Vespine (talk) 23:27, 5 July 2016 (UTC)[reply]

Pressure can accelerate burning rate, even to the extent of a deflagration to detonation transition. And partially constraining something that releases energy can increase the amount of energy directed in a certain direction (increasing the general acceleration of reaction due to pressure and/or the destructive power at a certain area). Constraining or putting many devices close together prevents energy loss to the surrounding air, which can cause temperature to increase more than usual, which acclerates reactions (and possibly leads to other reactions that don't occur at expected temperatures). DMacks (talk) 03:22, 8 July 2016 (UTC)[reply]

Attempting to identify this insect

Found a mile or so inland on the Sonoma Coast in California.

http://imgur.com/a/VFK9P

Thanks in advance! Waggie (talk) 16:31, 5 July 2016 (UTC)[reply]

Beautiful photos - worth uploading to Commons. You are in the top 5% of people asking for insect IDs around here.

Looking at them, I'd say that this insect has wing covers (elytra) instead of forewings, which puts it into the "sheath-winged" category of Coleoptera. It has filiform antennae with, oh, by counting I'd guess 11 segments but I'm likely to be off by one. (See [13]) for terminology. It has overall a fairly primitive appearance; this is not a scarab beetle, say, but seems like a fairly generic insect.

Now given that the antennae are longer than the body, I'm tempted to call this a longhorn beetle of some sort. There is such ridiculous variety among beetles that this doesn't come with a guarantee, but it's a place to start. Before we get too paranoid, note this doesn't look at all like an Asian longhorn beetle, so don't worry about that. Anyway, it's possible to start there and navigate taxonomy at sites like this, but I wouldn't expect this to be as easy as the usual case because we're dealing with beetles here. I can see some boring beetles with the same number of antenna segments (give or take one) as I counted in your photo, a few with antennae that long... not nearly enough. We're not getting through this gate with a pick gun; we're gonna need a key. Going to [14], I fooled around and got a list of five possibles based almost entirely on saying yes to "head distinctly elongate, forming a muzzle". I think that is true, but this isn't something I've done. The five are Compsocerini Rhagiomorphini Rhinotragini Stenoderini Uracanthini. The catch is that sample photos don't really make one look any better than the others; they all seem too graceful of wing, so to speak. And the suck is that that's just the first of five options from [15]. Their higher level key may allow me to narrow things down to Lamiinae and Cerambycinae (the one I used as an example above), based largely on my perception that there's a really short second antennomere (antennal segment). So it might be one of those five, but I don't know; even in those there is digging to do. So far, haven't struck gold yet. (That's a wonderful site and I should have gotten to an answer, but I'm not sure how to answer many of the questions) Wnt (talk) 21:00, 5 July 2016 (UTC)[reply]

I just went back and did a little random browsing of Compsocerini and initially got excited by an intriguing photo [16] but without annotation (the page linked to by bing images was blank, but it said it was a "eucalypt ringbarker longicorn", which is unfortunately just as vague. Phoracantha is an imported pest in California and so it is tempting, but the examples I see have spines on many antennomeres and too recognizable a pattern on the elytra. For all I know the image was mislabeled in the first place anyway. But I don't think this is very far phylogenetically. Unfortunately the key used above doesn't resolve down to species. Searching compsocerini on PubMed gets no results; searching compsocerini key on Google Scholar got me to this dissertation. This is absolutely stunning, one of the most gorgeous taxonomic works, richly illustrated, that I have come across (if only because I look so infrequently, and haven't done so much lately). Alas, many of the characters they look at are hard to assess even with your excellent photos; and worse, looking through the pictures makes me realize that some of the aspects of body shape that I was looking for in a search by eye really vary widely within many different groups and in any one of them there are beetles that look a little bit like this one. (Homoplasy) There is still an answer here, but it requires a more careful approach. Wnt (talk) 13:25, 6 July 2016 (UTC)[reply]

Equation of plane

moved to mathematics reference desk

Juno orbiter

I've read that the Juno orbiter will be deliberately crashed into Jupiter once it has completed its 37 orbits, because it might contain minute traces of Earth life, and if it happens that some of Jupiter's moons harbour life of their own, the Earth life might contaminate or even eradicate it. Does this mean we cannot ever send a lander, let alone a manned mission, to Jupiter's moons?

And also, I'm quite sure I've asked this before, but I noted that the spacecraft carries three special Lego minifigures, which are made of aluminum instead of plastic to withstand the harsh conditions of space. What's the point of this, given that no one will ever see them in space? But anyway, it was Lego, not NASA, who paid for them, and it's not like the money ever actually left Earth. JIP | Talk 22:09, 5 July 2016 (UTC)[reply]

I would imagine that landers would be held to an even higher level of scrutiny than satellites to make sure they don't leave Earth carrying contaminants, but I'm not sure if there's a way to be completely sure a lander wouldn't cause contamination. As for the second question, it's really just a symbolic thing, as the minifigures represent Galileo, who discovered the moons orbiting Jupiter, and the Roman gods Juno (namesake of the orbiter) and Jupiter (namesake of the planet). clpo13_(talk) 22:15, 5 July 2016 (UTC)[reply]

Actually, to take this contamination thing even further, strictly speaking, we cannot ever send anything to any heavenly body we are not completely certain is lifeless. The common sci-fi scenario of meeting extraterrestrial life is never going to happen, as we are actively trying to prevent it. Might it be possible if we first find evidence of existence of extraterrestrial life without risking contaminating it? JIP | Talk 22:22, 5 July 2016 (UTC)[reply]

COSPAR (Committee on Space Research) have rules for how deeply sterilized a spacecraft has to be, and these vary depending on the target. Where there is a chance of contamination (Mars is the obvious example), cleanroom assembly, extensive disinfecting and constant monitoring is required to ensure the spacecraft is clean. Where contamination is unlikely to cause problems, there only needs to be risk assessment and reporting in the event of the spacecraft impacting a body. An orbiter around Jupiter is Category II, so it doesn't need extensive cleaning, but a lander on Europa (the only moon of Jupiter so far assessed) would be in the much more rigorous Category IV. So we certainly can send a spacecraft to Europa, it'll just cost more and take longer to build. Smurrayinchester 14:42, 6 July 2016 (UTC)[reply]

(Edit: Ganymede has also been investigated. It is provisionally Category II) Smurrayinchester 15:03, 6 July 2016 (UTC)[reply]

Our article: Planetary protection. -- ToE 12:21, 6 July 2016 (UTC)[reply]

July 6

Robin mother won't feed chicks

We have a American robin nesting in a hanging plant on our patio. She laid 3 eggs and all three hatched. But she doesn't seem to be feeding them and they are all quite lethargic. It's been several days now. There is a male nearby, presumably the father, and I understand that the males are rather standoffish, as is this one. I am considering putting some bait worms and berries in the nest so hopefully the chicks will eat, regain their strength, and start chirping for more, triggering the mother robin's instinct to feed them. What do you think of this plan ? StuRat (talk) 00:27, 6 July 2016 (UTC)[reply]

I think nature is red in tooth and claw. This borders on medical advice ;) anything we advise here could go terribly wrong. There's a widely held belief that birds have keen smell and if you merely "touch" a nestling you are likely to get it rejected by the parents. I have read that this is "generally" untrue, but, I think you'll just need to proceed at your own caution. If it were me, I would leave nature to it self. Maybe there's something "wrong" with them and if they don't survive to adulthood, they wouldn't "make it in the wild" anyway? And you feeding them is just prolonging the suffering. Vespine (talk) 01:25, 6 July 2016 (UTC)[reply]

That is generally untrue; with a few exceptions, birds tend to have a poor sense of smell. However, they do tend to have excellent vision and, given the importance of the location, I doubt it will be possible for the OP to mess around with the nest without them being seen. The tampering may have already signaled to the parents that the nest should be abandoned as dangerous. FYI, robins are likely covered by the Migratory Bird Treaty Act of 1918. Matt Deres (talk) 02:36, 6 July 2016 (UTC)[reply]

Another exception possibly being homing pigeons using olfactory navigation. Vespine (talk) 04:16, 6 July 2016 (UTC)[reply]

Birds know when to hold 'em and when to fold 'em. Robins tend toward starving the weakest in tough times. Very few animals need reminders about needing food to live; even the bird-brained have been doing this longer than we have. A chicken of mine recently killed her own premature baby, an hour or so after I went "D'aww!" at its wobbling and started thinking of names. Life sucks sometimes.

Helping the less fortunate is generally the nice thing to do, but helping creates caring, and caring for someone you can't save is taxing while they're alive and painful when they die. On the bright side, robins usually won't starve all three. I'll wish the big one well. InedibleHulk (talk) 07:48, July 6, 2016 (UTC)

Robins are born altricial i.e. with no feathers, eyes closed, entirely dependent on parents for food and warmth. If an adult bird does not return after about three hours then rescue will be necessary. A small bird will die if it doesn't eat for 48 hours. All too often baby birds are "rescued" unnecessarily, see TO “RESCUE” OR NOT - BABY BIRDS. Birds in rehabilitation should not be reared on worms. AllBestFaith (talk) 09:27, 6 July 2016 (UTC)[reply]

UPDATE: We left berries out on the patio, and they disappeared. That doesn't necessarily mean the robins ate them, as we have other critters around, but the chicks are doing better now, and we see the chicks' beaks wide open and begging for food. StuRat (talk) 00:55, 8 July 2016 (UTC)[reply]

Does cannibalism cause insanity?

According to Kuru (disease), a prion found in humans could cause insanity. However, do all humans have this prion? If the brain is not eaten, or the meat is thoroughly cooked, would cannibalism be healthy?--Hofhof (talk) 13:45, 6 July 2016 (UTC)[reply]

Yes. But don't eat too many near relatives. YohanN7 (talk) 14:02, 6 July 2016 (UTC)[reply]

According to this source, prions can only be "deactivated" by incinerating at 900 degrees Fahrenheit (482 Celsius) for 4 hours, by which time, your brain recipe would be seriously overdone. I shan't be going to your house for dinner, thank you all the same. Alansplodge (talk) 17:10, 6 July 2016 (UTC)[reply]

Humans don't all have the prion. The natural incidence of Creutzfeld-Jacob disease is quite low, and I have read claims it is less transmissible by eating than vCJD or kuru. The existence of multiple types of misfolded PrP is truly one of the weirdest things in biology - it's almost like a genetic system coded in the misfolding of a protein, which is utterly mysterious. That said, the incidence of diagnosed CJD will inevitably be lower than the incidence of some prions loose in the brain of someone simply thought to be a little old and a little slow by the time of death. Even supposing there is some kind of collective social memory of these risks, I've never understood how great armies, in times when there has been little reluctance to commit atrocities or suffer casualties, would risk starvation or at least degradation of combat readiness while camped in the middle of so much freshly slaughtered meat. Wnt (talk) 17:37, 6 July 2016 (UTC)[reply]

Japanese war crimes#Cannibalism:

"Perhaps the most senior officer convicted of cannibalism was Lt Gen. Yoshio Tachibana (立花芳夫,Tachibana Yoshio)"

"The airmen were beheaded on Tachibana's orders. Because military and international law did not specifically deal with cannibalism, they were tried for murder and "prevention of honorable burial"." Sagittarian Milky Way (talk) 10:06, 8 July 2016 (UTC)[reply]

"It's simply not done" applies to a multitude of activities. -- Jack of Oz ^{[pleasantries]} 22:45, 7 July 2016 (UTC) [reply]

Point at which pressure converts solid into liquid

Is there a term for the collection of points at which pressure causes a solid to become a liquid? For example, "At -17°, ice becomes water at [pressure 1], as it does at -5° at a pressure of [pressure 2]. These points, together with other points manifesting the same phenomena, are known as the [term that I'm looking for]". Nyttend (talk) 16:28, 6 July 2016 (UTC)[reply]

Pressure melting point? I don't think there's a more specific term, it is simply the melting point defined at a given pressure. —Akrabbim^talk 17:06, 6 July 2016 (UTC)[reply]

Thanks; all I could think of was "triple point", and I knew it was wrong. Lake Vostok now improved with a link to pressure melting point. Nyttend (talk) 17:09, 6 July 2016 (UTC)[reply]

Phase diagram Wnt (talk) 17:30, 6 July 2016 (UTC)[reply]

It could be termed a phase boundary, but this is more likely the term for the physical surface of the ice water interface. Phase diagram boundary is a bit more descriptive. Diagrams can be multidimensional if you add some other aspect, such as a range of compositions, eg salinity, isotope composition, size of container, that can vary the melting point. Graeme Bartlett (talk) 23:28, 6 July 2016 (UTC)[reply]

Solidus - defines a line in pressure temperature space - see also liquidus (not just varying with temperature as that article says, but other variables including pressure, as Graeme mentions above) where you get 100% liquid. Mikenorton (talk) 09:18, 8 July 2016 (UTC)[reply]

Although that's only for a two or more component system, which is what I think of when hear the term phase diagram, so that wouldn't be appropriate for water. For a single component they're called "phase lines" as in the "solid/liquid phase line" here. Mikenorton (talk)

Heavy duty breakers

I often see heavy duty breakers being used for road works to dig up the road. They are very loud and I'm assuming cause a lot of vibrations. Can they not damage or causes cracks in nearby houses and other structures especially if they're old and weak for example old brick and timber houses? Clover345 (talk) 16:41, 6 July 2016 (UTC)[reply]

Yes. It's uncommon but not unheard of for restrictions to be placed on the use of such machinery when work is undertaken within the vicinity of buildings which might be affected by undue vibration - example in this Daily Hate story about Robbie Williams. I'm sure there's literature on the transmission of vibration through local terrain, and its effects on structures, but I can't point to any right now. --Tagishsimon (talk) 16:50, 6 July 2016 (UTC)[reply]

The article about jackhammers (pneumatic drills or demolition hammers in British English) used to break roadways mentions their bad health effects and here and here are safety warnings. This analysis includes in Table U-2 a summary of construction equipment vibration levels and effects on humans and buildings. AllBestFaith (talk) 18:11, 6 July 2016 (UTC)[reply]

And that's not mentioning the effects on pregnant women. --71.110.8.102 (talk) 21:58, 6 July 2016 (UTC)[reply]

July 7

Wind strength of compressed air

Imagine an invisible field that takes the form of a sphere 1000 meters in diameter filled with air. It is shrunk to a diameter 0.1 meters in diameter. Place it at sea level and shutdown the field. What would the strength of the resulting winds be? — Melab±1 ☎ 00:27, 7 July 2016 (UTC)[reply]

During your magic step that causes the sphere to shrink and the air to become compressed, are you assuming isothermal compression or adiabatic compression or something else? This important detail changes everything - including the equation(s) you need to apply - for the resulting pressure and temperature of the gas inside the sphere. Nimur (talk) 01:37, 7 July 2016 (UTC)[reply]

Would such hypothesized compression change it into a liquid or maybe solid state? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:40, 7 July 2016 (UTC)[reply]

No way! 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 07:26, 7 July 2016 (UTC)[reply]

Remind me as to what isothermal compression would do. All I had in mind was this acting like a spring with just compression. — Melab±1 ☎ 21:46, 8 July 2016 (UTC)[reply]

The wind will almost certainly be turbulent, which doesn't help matters. Where the hyperpressurised air (which, as the IP above points out, would be above its critical point and therefore would become a supercritical fluid) meets the normal air, all sorts of weird turbulence things would start happening along the boundary, which means that to calculate how the air actually flows, you'd need to solve the nasty Navier–Stokes equations. You could try simulating it with Computational fluid dynamics - there are lots of CFD simulators available online, although many of them are very hard to use. Smurrayinchester 08:23, 7 July 2016 (UTC)[reply]

First I would point out that a compression of 1e12 is ridiculous.my approach would be to work out the potential energy of the resulting sphere,eqate it to tons of TNT,and look up the effects of a groundburst of that size of bomb. The windspeed can exceed Mach 1. Greglocock (talk) 09:46, 7 July 2016 (UTC)[reply]

Sadovsky formula is a good phrase to search for.Greglocock (talk) 10:22, 7 July 2016 (UTC)[reply]

Ridiculous in what way? Mach 1 seems too low. — Melab±1 ☎ 21:46, 8 July 2016 (UTC)[reply]

The density of the compressed air would be about 10⁹ kg/litre. This similar to white dwarf matter but below that of neutron star matter. The pressure would be very extreme. perhaps 10¹⁶ atmospheres. Heisenberg's uncertaintly principle can get a handle on the speed. Also this pressure is likely enough to trigger fusion of oxygen and nitrogen. Graeme Bartlett (talk) 13:27, 7 July 2016 (UTC)[reply]

I didn't think it would be that dense. What would oxygen-nitrogen fusion look like? Is it even a common thing in stars? — Melab±1 ☎ 21:46, 8 July 2016 (UTC)[reply]

Total solar eclipse

Maps showing the band of totality of the solar eclipse of August 21, 2017, such as this one, usually show a line at the center of the band. What does this line represent?

I know that obscuration is at least 100% everywhere in the band, increasing slightly above 100% as you move toward the center. What is the difference in the viewing experience near the inside edge of the band, as compared to that at the center, if any?

I have a brother who lives in Kansas City. I used an online tool to determine that his house will see 99.97% obscuration, being just outside the band. I assume that it will be worth the short drive to get within the band, but would it make any noticable difference to drive farther north? It would be an hour's drive to St. Joseph. ―Mandruss ☎ 08:58, 7 July 2016 (UTC)[reply]

The duration of totality. The line at the centre of the band of totality indicates where totality lasts longest. If you're just inside the band of totality, it only lasts for a few seconds. Close the the centre, it may be more than 5 minutes. On the other hand, close to the edge the effects associated with beginning and end of totality (Baily's beads) will last a bit longer. If you want to see the corona, go for the centre. If there are scattered clouds, a longer duration means more chance to see something. PiusImpavidus (talk) 09:53, 7 July 2016 (UTC)[reply]

Ah, now I see. According to this tool, totality in that area, at least, will range from about one second just inside the band to about 158 seconds at the centerline. I suspect he'll go to the center. ―Mandruss ☎ 11:35, 7 July 2016 (UTC)[reply]

It could be worse. 30 years ago there was a flash totality in the ocean that was slightly over 0.15 seconds. Sagittarian Milky Way (talk) 09:49, 8 July 2016 (UTC)[reply]

Snake ID?

This snake fell on my mother as she was walking out the front door of her house this morning. She's located in Southern Oaxaca, Mexico, right on the coast. They called it a "ratonero." Any thoughts? I apologize about the picture quality. Could it be... a fer de lance? Pics. Justin15w (talk) 15:43, 7 July 2016 (UTC)[reply]

First, always assume it's dangerous if you don't know what it is. Second, we'd probably need a much clearer shot of the head, pix, but see the first point. There is also the point that ratonero means "rat hunter", and there are many different species of "rat snake" world wide, some of which look very similar to this specimen. Finally,I do not see the term ratonero used to describe the fer de lance at Spanish wikipedia (where it has a lot of local names, mostly dealing with appearance) or elsewhere on the web. μηδείς (talk) 18:22, 7 July 2016 (UTC)[reply]

This is frustrating. The image quality is not good enough for me even to hallucinate an answer to whether there are loreal pits; clearly, identifying a pit viper would be a useful start here. The shape of the head seems suggestive, but I don't know how misleading it can be. Searching ratonero serpiente on Bing got me something with similar-ish black rings, but they become staggered into a zigzag later and there aren't clear black rings on the side of the body. [17] Worse, it's labeled merely "Vibora" (viper). So I don't think I'm beating it that way. I just don't have enough image to work with to do this any proper way. But maybe a decent naturalist will just recognize it... Come to think of it, I don't know why with all the fancy-dancy AIs out there that claim to keep track of individual people by their faces can't solve the question of which snake is on a low-res photo. Wnt (talk) 19:58, 7 July 2016 (UTC)[reply]

When AI gets to that point, think either Matrix or Terminator.

What appears, to me, to be the wider hind jaw makes the snake look more like a viper such as the fer de lance, rather than a colubrid, which includes Elaphe and the other rat snakes. (Think rattlesnake or adder for viper, and gartersnake for colubrids.) I am wondering if there' a zoo or university of Oaxaca we could contact. μηδείς (talk) 21:01, 7 July 2016 (UTC)[reply]

I think I will conclude by saying that the question is not either or. This doesn't have to be either a fer de lance or a rat snake. It could very well be an anaconda. (Well, no, not an anaconda, but I assume you get the point; we lack the data.) μηδείς (talk) 22:06, 7 July 2016 (UTC)[reply]

@Justin15w:, do either you, your mother, or someone handy speak Spanish? I have looked at some websites re schools in Oaxaca, but they have been "under construction" or otherwise not very helpful. What I would do here in the states is call the main directory for NYU, Cornell, Rutgers, or another local school and as for the biology department, and could I email them a picture. If you (pl.) are not Spanish speakers yourselves, I can help, but I am just not sure which local school would be the best to contact. μηδείς (talk) 23:55, 7 July 2016 (UTC)[reply]

The photo is indeed blurred, but provides contradictory clues. The head is wide at the back and narrow at the front,and seems to transition to a skinny neck and its wedge shape suggests a pit viper. The tail tapers very gradually, unlike certain venomous snake I have met such as water moccasins. In the US, at leas, venomous snakes (except coral snakes) have fat bodies. I would stay the hell away from it. The Wikipedia articles on various poisonous snakes such as fer de lances (or fers de lance if you prefer) have lousy illustrations. The Wikihow article on identifying poisonous snakes might almost be a humor piece from The Onion, since it says to examine the scales on the bottom of the snake's tail, then it says to examine the bite marks on your hand. Edison (talk) 03:56, 8 July 2016 (UTC)[reply]

Railway Prince Rupert–Valemount

When was the railway line from Prince Rupert to Valemount in British Columbia built?--Kopiersperre (talk) 16:04, 7 July 2016 (UTC)[reply]

The Valemount article mentions that the station was moved there in 1927. Rojomoke (talk) 16:24, 7 July 2016 (UTC)[reply]

More information at Rails Over the Mountains: Exploring the Railway Heritage of Canada's Western Mountains by Ron Brown. A station opened at Swift Creek in 1915 and was moved (presumably the whole station building was moved) to Valemount in 1927. It was moved again to become the local museum in 1992. Alansplodge (talk) 16:55, 7 July 2016 (UTC)[reply]

See also the Valemount Museum website which gives a date of 1914 for the original building, which it says was in "a town called Swift Creek [which] was just up the creek". Alansplodge (talk) 16:55, 7 July 2016 (UTC)[reply]

SIGNIFICANT DATES IN CANADIAN RAILWAY HISTORY gives a date of April 7, 1914: "Grand Trunk Pacific Railway main line is completed between Winnipeg, Melville, Edmonton, Jasper and Prince Rupert. The last spike was driven at a location 93 miles west of Prince George, BC". Alansplodge (talk) 17:02, 7 July 2016 (UTC)[reply]

Main Battle Tanks

Are the NATO tanks armored with composite armor at the sides of the hull ? 94.249.30.80 (talk) 21:14, 7 July 2016 (UTC)[reply]

Yes. 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 21:31, 7 July 2016 (UTC)[reply]

...And no. 2606:A000:4C0C:E200:650F:AAC:B91D:D63C (talk) 22:49, 7 July 2016 (UTC)[reply]

Does the "Main" modify "battle" or "tank?" Edison (talk) 03:35, 8 July 2016 (UTC)[reply]

Well it's both: of the things called "battle tanks", this is the main one. Or is this a joke I missed? Yes battle tank links to the same article, but it explains that even though there are still "light tanks" which are battle tanks, it's more of a historical distinction when there used to be light, medium, heavy and super-heavy battle tanks. Vespine (talk) 04:39, 8 July 2016 (UTC)[reply]

Ultra-heavy tank aka leviathan aka landship. Indestructible. Sinks into and gets stuck in any soil it drives on. After one passed road can't be used by anyone. Has many decks. Sagittarian Milky Way (talk) 06:16, 8 July 2016 (UTC)[reply]

Like this one? ;-) 2601:646:8E01:7E0B:ECDB:601F:4E1E:971F (talk) 06:52, 8 July 2016 (UTC)[reply]

More like this land leviathan perhaps? ;-) Dmcq (talk) 07:59, 8 July 2016 (UTC)[reply]

Pfft, all that for only 100,000 square miles? How land-starved can you be? Sagittarian Milky Way (talk) 09:24, 8 July 2016 (UTC)[reply]

Well people , thank you for your contributions , but I`m asking about : M1 Abrams , Challenger 2 , Leclerc and Leopard 2 . Also note that I`m not asking about the added external armor modules , I`m asking about the main body of the tank .149.200.213.154 (talk) 08:29, 8 July 2016 (UTC) I think you want to say : if tanks were heavily armored from sides they will be immobile .149.200.213.154 (talk) 09:21, 8 July 2016 (UTC)[reply]

Safety valve

I am currently looking for a high-pressure safety valve, but can't find one which meets all my specs -- I found one which has the right inlet size, but the maximum pressure is too low (above the working pressure for my apparatus, but far below the normal peak pressure due to water hammer, which means it will open momentarily on each and every startup), and another which has the right maximum pressure, but its inlet is too small. Out of these two evils, which is the lesser one -- or are these both completely unacceptable? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 23:17, 7 July 2016 (UTC)[reply]

The first one sounds safer, as the 2nd one may not drain off the water fast enough to prevent pressure build-up. Some suggestions:

1) Find a way to start up the system gradually, to reduce the water hammer. Do you start up a pump ? Then start it at reduced voltage (ensure that this is safe for the pump first). Do you open a valve to start the system ? Then open it more slowly. This solution may have other benefits, like reducing the wear and tear on the system.

2) Let some water be released during startup. Of course, the acceptability of this solution depends on the situation. In something like a lawn sprinkler system, losing a bit of water is probably fine, as long as it drains safely into the lawn.

3) Use more than one of the smaller safety valve, so that the max flow rate is the same as the large safety valve. Of course, this may involve cutting pipes and joining them back together. This should actually be safer than a single safety valve, especially if the safety valves are widely separated. StuRat (talk) 01:20, 8 July 2016 (UTC)[reply]

Well, of these 3 choices, (1) is not really an option -- the pump gets its power directly from the mains with no voltage regulation (other than overvoltage protection). (2) is actually OK -- I expect the blowdown volume to be small, and although the liquid is somewhat hazardous (dilute phosphoric acid with copper salts), the discharge line will drain it directly into a waste container. (3) is possible, but will add cost and complexity. So I think I'll shop around some more, but if I can't find anything, I'll go with (2) -- especially since the pressure I'm looking for actually represents the worst case, and the actual pressure spikes could be much less. 2601:646:8E01:7E0B:ECDB:601F:4E1E:971F (talk) 07:21, 8 July 2016 (UTC)[reply]

Is the problem with the inlet size merely that it doesn't match your system connections, or that it would not provide adequate flow to relieve your overpressure quickly enough? Usually pretty trivial to get or build adapters for any pipesize differences as long as the relief itself actually works well enough. StuRat makes a good point that avoiding the water-hammer itself by careful system control or (re)design might be better in the long run. Another option for that is an air tank that can act as a damper to even out the pressure (lots of residential and commercial water systems have these). DMacks (talk) 03:06, 8 July 2016 (UTC)[reply]

The maximum flow is actually pretty small, so the flow through the relief valve will in fact relieve the overpressure -- the only problem is that the connections don't match. And my apparatus does in fact include an air chamber (an improvised one -- an upward-pointing dead-end pipe with its top end capped, like in a residential system but bigger and with a high pressure rating), so the pressure spikes will definitely be smaller than my worst-case calculations predict -- the only problem is, I couldn't do any testing of the system (not without a safety valve!), so I don't know how much smaller. So, with all that in mind, would it be better to use (1) the lower-pressure valve which fits the connection (which might or might not waste the reagents upon startup), or (2) the smaller higher-pressure one with an adapter? Also, if the better choice is (2), am I correct that the set pressure will have to be adjusted downward because of the smaller diameter? 2601:646:8E01:7E0B:ECDB:601F:4E1E:971F (talk) 07:21, 8 July 2016 (UTC)[reply]

You need to get both of those right. Safety valves which opened, but were too small to reduce pressure faster than it built up, have been a historic cause of boiler explosions. I'm surprised if water hammer is bad enough to open the valve though. Normally mechanical inertia (rather than spring pressure) is enough to avoid that. Maybe a larger (and so more massive) valve would be more resistant to it? If a system has water hammer to that level, I'd be concerned that the water hammer is going to be its own problem and needs to be addressed, probably by arranging an air reservoir. Andy Dingley (talk) 09:28, 8 July 2016 (UTC)[reply]

I actually don't know whether water hammer will open the safety valve -- it would according to my worst-case calculations, but I haven't tested (or even built) my apparatus yet, so I have no way to know for sure. And the plumbing does include an air chamber -- so the water hammer will be less than what I calculated (I just don't know precisely how much less). 2601:646:8E01:7E0B:ECDB:601F:4E1E:971F (talk) 09:59, 8 July 2016 (UTC)[reply]

My suggestion is option 2, just for testing purposes. If there is leakage, then I would revisit option 1. For example, a rheostat could be installed between the mains and device, allowing you to turn a dial to turn the voltage up. However, you would need to ensure that it's safe to run the pump at reduced voltage, even though it would only be for a second during startup. This is also far less work than cutting into pipes to install an additional safety valve. Note that the rheostat may overheat if used at low voltage, due to the resistor used. (The more common type of "dimmer switch" used these days rapidly turns the power on and off, instead, but this might not be good for the pump.) StuRat (talk) 16:22, 8 July 2016 (UTC)[reply]

Take a look at the valve closest to your requirements first. It probable came in a box of some sort with a label. Phone (not email) the company on that box and ask the switchboard to put you through to their Technical Department (rather than their customer help desk – as they just go by a script and are not tech people). Explain your application. Even if the company does not offer the right valve for you, these real tech people love to help and can redirect you to maybe a different company. Have a note-pad and pencil to hand when you phone so that you can right it all down. Andy Dingley mentioned an 'air reservoir', the tech dept however, might refer to such as a nitrogen bag accumulator. So when they say anything you don't immediately understand, question for clarification and write it down. I used to work in R&D and found it helpful (essential) to learn how to negotiate my way through a switch-board and get to talk to a person that had the right technical knowledge, making sure I had a note of their names, positions, tele ext etc., in case I needed to refer back to them at a later time. It sounds like your application is too specific for us to answer with out you suppling detailed information – and that is why technical departments exists. --Aspro (talk) 20:18, 8 July 2016 (UTC)[reply]

July 8

That thing that squishes dough

Does anyone know the common name for this? It is used in China and elsewhere to knead dough. Anna Frodesiak (talk) 08:52, 8 July 2016 (UTC)[reply]

The term rolling pin is pretty ubiquitous in the English speaking world.--Aspro (talk) 11:18, 8 July 2016 (UTC)[reply]

It's a fiener - I think that's the Yiddish term for them, when they're used for working matzah. They're quite specific to the types of dough they're used with. Most bread making uses a dough hook to emulate hand kneading and the stretching of dough, but a fiener instead squashes the dough. I think this type of squash kneading is only used with unleavened doughs, such as matzah and noodles.

A rolling pin should work the dough as little as possible. It's for shaping the dough flat, not kneading it to change its properties. Andy Dingley (talk) 11:27, 8 July 2016 (UTC)[reply]

I agree with AD. One is not trying to activate the gluten (takes too long). One is just making it a consistent and well textured dough. Same with some noodles. Wheat noodles can be stretched by hand because the gluten has be activated but others are extruded (like spaghetti). But Fiener is a term exclusively for matzah. This is why I suggested rolling pin to cover all nationalities. (Note: I hasten to add that I'm not referring to 'real' spaghetti which as every one knows comes from the Spaghetti Trees of Europe but to the extruded stuff Americans buy from their supermarkets BBC: Spaghetti-Harvest in Ticino.

Hepatitis B carrier can bring children without to transfer them his virus?

A man has an hepatitis B and his wife doesn't have hepatitis at all, and they want to bring children. Is there any way to make it safty without to transfer it to their child (Eccept of IVF)? 194.114.146.227 (talk) 09:10, 8 July 2016 (UTC)[reply]

In your hypothetical couple, your question is "is hepatitis B virus transmitted via the male germ line?". Given this study, the answer would seem to be no. If a child is born with hepatitis B, it's because the mother is infected and has transmitted it to the fetus. It might be worth mentioning that there are medical options available for mothers who are hepatitis B positive that may prevent hepatitis in their children, which generally would involve giving immune globulin and hepatitis vaccine to the newborn child. But any non-hypothetical couple would surely consult their physician to get medical advice before proceeding. After all, if the man and woman are having sex, he should be concerned about transmitting Hepatitis B to his wife. And she could be vaccinated to prevent her from becoming infected, and if she doesn't become infected, neither will her future fetuses. This is known as "pre-conception hepatitis B vaccination".- Nunh-huh 10:27, 8 July 2016 (UTC)[reply]

The wife should be vaccinated against hepatitis B regardless of any intention to have a child - just to prevent infection, which may cause long term health problems. Ruslik_Zero 16:54, 8 July 2016 (UTC)[reply]

This sounds awfully like a request for medical advice ("I have this friend who has Hepatitis B..."). Anyone who has questions regarding a health condition they have should consult a health care professional. --71.110.8.102 (talk) 20:50, 8 July 2016 (UTC)[reply]

Bristles on Zora

Hello! I found a Zora species in Ireland, and I would like to identify it. In [this key], it asks in couplet 1 how many bristles it has on its first and second metatarsus. Anybody have any ideas as to what the differences are between setae, spines and bristles? Thanks, Megaraptor12345 (talk) 12:54, 8 July 2016 (UTC)[reply]

@Megaraptor12345: ~~The Zora are piscine humanoids.~~ Going by seta and spine (zoology), setae and bristles are synonymous for (basically) "hair" (i.e., flexible) while spines are rigid. I am not sure how that distinction applies in your context though. Tigraan^{Click here to contact me} 14:24, 8 July 2016 (UTC)[reply]

Californian bird that smashes snails?

I live in Southern California, and last year around Christmas I found a bunch of broken snail shells at a local park. (photo) The way they're broken looks similar to those crushed on rocks by the British song thrush. Could these shells I saw have been smashed by a local bird in a similar way? There were lots of American robins and a few hermit thrushes around when I found those smashed shells, so I was wondering if they break snails like song thrushes do. 2602:304:B041:2949:E9C7:FF65:AF81:67C2 (talk) 14:25, 8 July 2016 (UTC)[reply]

Bombs used by US police

In 1985 the Philadelphia police dropped a bomb or bombs on a building held by MOVE activists, causing an explosion and fire which killed 11 people and a fire which destroyed 65 buildings. In the recent Dallas police shootings, the police used a bomb robot to carry a bomb to the location of a shooter and blow him up, without destroying the building or neighborhood. Do US big city police departments have bombs or grenades as part of their official equipment? Do they have RPGs, or other military weapons designed to kill perpetrators when automatic weapon fire is not enough? It seems chancy to expect them to just build a bomb and detonator on the spot. The Move case might be considered as an attempt to gain entrance to the building or to disable a generator on the roof, and not as a clear effort to kill the people in the building. Besides today's use of a police bomb to kill the suspect, are there any other cases in US history where US police or FBI (not military) outside actual wartime used a bomb with the clear intent to kill a suspect, shooter, or perpetrator, not including cases where teargas cause a fire (such as Waco or the SLA shootout)? Edison (talk) 16:49, 8 July 2016 (UTC)[reply]

Contaminating Jupiter

Let's imagine some Johnny Appleseed sabotaged the Lego figurines aboard the Juno, filling each one with hardy endospores in a mirrored thermos and a teeny burst charge set to go off when the atmospheric pressure rises to about 1 atm (which is a region with liquid water clouds in the atmosphere of Jupiter. Is it believed that Earth bacteria could colonize these clouds? How visible would the effect on Jupiter be? Wnt (talk) 16:55, 8 July 2016 (UTC)[reply]

You can find a wide range of atmospheric densities, so there might be an altitude at which something deployable from a probe would float, regardless of whether the individual bacteria would float. Lego plastic is ABS which has a density of 0.9 g/cm3 - 1.53 g/cm3 : median 1.07 g/cm3. The article on Jupiter's atmosphere refers to pressure gradients rather than density, so it's not clear at what level a Lego might float suspended, or a bacterium might float, or whether it would be quickly melted or sterilized. On Earth, updrafts can keep hail suspended in clouds until it is larger than a baseball. Might similar boluses of high density material be suspended by updrafts on Jupiter? There is high radiation in space near Jupiter. Would atmospheric radiation or high temperatures or toxic gases quickly sterilize all known extremophiles from Earth? Edison (talk) 17:17, 8 July 2016 (UTC)[reply]

The Legos that were sent with Juno were not the standard Legos. They were specifically made of aluminum for the mission. And the OP's question isn't about the figures, it's about endospores sent with the figures. Dismas|^(talk) 17:43, 8 July 2016 (UTC)[reply]

Thanks for the correction. The standard Lego has about the density of water, or of a drop of water or bit of water ice contaminated with bacteria. The point is that a spaceprobe has some components with low density. If contaminated, could they float at some altitude after the probe breaks up during entry? Do water drops or ice swirl about in the Jovian atmosphere?Edison (talk) 19:20, 8 July 2016 (UTC)[reply]

First, water clouds in the Jovian atmosphere are thought to lie in the pressure range from 3 to 7 atm, not 1 atm. Second, I doubt that any terrestrial life can survive there due to presence of toxic compounds and lack of necessary nutrients. Ruslik_Zero 20:19, 8 July 2016 (UTC)[reply]

UHD: How does forward compatibility work?

I read Wikipedia's article Ultra-high-definition television but I am wondering about something. If a program is broadcast in UHD, how do older TVs (1080p) display the program? A friend was telling me that the older TVs can just downgrade the signal, but I am doubtful about that. Wouldn't the broadcaster have to send out two separate signals, one with the program in HD and another in UHD? I'm not talking about Netflix or anything like that, I'm referring to free service from regular TV stations (such as the Rio Olympics on NBC, or in a couple of years presumably all primetime US network programming will be UHD). Mathew5000 (talk) 17:35, 8 July 2016 (UTC)[reply]

Clock accuracy on spacecraft like Juno

Apparently the Deep Space Atomic Clock, in development at NASA, will be accurate to within 1 nanosecond every ten days. How accurate are the clocks on current NASA space missions such as Juno? (I know that there is some drift due to relativistic effects, but that can be predicted and compensated for; what I'm asking about is the inherent accuracy of the clock itself.) It was reported that the orbital insertion at Jupiter hit its target "within one second"[18], but was the timepiece accurate enough that it stayed within much less than a second, since departing Earth in 2011? Or was it kept synchronized with clocks on Earth by other means, and if so what? For example, I've heard about using eclipses of the Jovian moons to synchronize timepieces. Or the obvious, send a radio signal and have the spacecraft send a timestamped response immediately on receipt but that method must introduce other inaccuracies and also depends on knowing position. Mathew5000 (talk) 21:03, 8 July 2016 (UTC)[reply]

Effect of a magnetar-strength magnetic field on matter

The magnetar article claims that "The magnetic field of a magnetar would be lethal even at a distance of 1000 km due to the strong magnetic field distorting the electron clouds of the subject's constituent atoms, rendering the chemistry of life impossible.". So if the magnetic field of the Earth became that strong, what would happen to matter? Would it fall apart? Would I be able to walk through walls (since electromagnetism gives solids their solidity)? — Melab±1 ☎ 21:56, 8 July 2016 (UTC)[reply]