This article is within the scope of WikiProject Astronomy, which collaborates on articles related to Astronomy on Wikipedia.AstronomyWikipedia:WikiProject AstronomyTemplate:WikiProject AstronomyAstronomy
This article is within the scope of WikiProject Astronomy, which collaborates on articles related to Astronomy on Wikipedia.AstronomyWikipedia:WikiProject AstronomyTemplate:WikiProject AstronomyAstronomy
@Nwbeeson: Please see the edit I have just done. These diagrams are for a rotating frame of reference, which means Jupiter stays almost stationary over on the right. So I don't think the diagrams should show the orbit of Jupiter as a circle or a line segment. Eric Kvaalen (talk) 19:57, 6 April 2017 (UTC)[reply]
@Eric Kvaalen:Yes, that is wonderful. I did not pay enough attention to the fact that the original data is in the rotating frame with Jupiter stationary. I have edited, the originals to put Jupiter in its place. Thanks for the help, it is a demonstration of the power of Wikipedians working together to get it right. Nick Beeson (talk) 20:08, 10 April 2017 (UTC)[reply]
“It is very extreme—particularly since they don’t have any dynamic modeling approach—to support their ideas is by saying that everything else is impossible,” says Southwest Research Institute scientist Hal Levison, who wasn't involved with the new study. ... Bottke and his colleague David Nesvorny suspect that BZ509 is actually an inactive comet from the Oort Cloud, a zone of icy debris on the far outskirts of the solar system. After being nudged long ago into a backward orbit, it could have entered its current loop just a few million years ago, they suggest.
Reading the paper I came across this:
"However if such orbits exist then they are the ones that correspond to the actual motion of the asteroid and not the short-lived unstable orbits. Choosing the former orbits over the latter is motivated by the Copernican principle that 2015 BZ509 is not being observed at a preferred epoch in Solar system history."
They are assuming that since there search identified some stable orbits exists (27 out of 1 million) the object must be in that orbit because otherwise we are observing it at some special time. But there is another possibility: many objects could have spent a short time in a similar orbit and BZ509 is just the current example. Concluding that this object has been on its orbit since the beginning of the solar system instead of being one of many temporary objects should only follow a study of the probability of comets from the Oort cloud entering this orbit. Agmartin (talk) 20:42, 21 May 2018 (UTC)[reply]
An interstellar origin would have one advantage: the drag from the gas in the protoplanetary disk could slow an object into a circular orbit, retrograde objects would likely spiral into the sun so it would require good timing relative to the loss of the gas. There was even a recent article discussing this. This might also work for solar system objects too if they were captured in the Oort cloud then soon after were perturbed by a nearby star and reentered on a retrograde orbit. Agmartin (talk) 20:55, 21 May 2018 (UTC)[reply]
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