Posted on 12/14/2005 10:12:29 AM PST by SunkenCiv
Astronomers working in Canada, France and the United States said they had found a small deep-space object, nicknamed Buffy, that challenges mainstream theories about the evolution of the Solar System. The rock lies in the Kuiper Belt, the name for the flock of objects beyond Neptune's orbit that are believed to be leftover rubble from the Solar System's building phase and are the source for many comets... Measuring between 500 and 1,000 kilometers (300 to 600 miles) across and taking about 440 years to make just one circuit of the Sun, Buffy is remarkable not for its size -- around half a dozen identified Kuiper Belt objects are bigger -- but for its location and orbital tilt... Buffy has an almost perfect circular orbit and encircles the Sun at an extreme tilt, at 47 degrees to the orbital plane of the planets as they swing around the Sun... Buffy is the temporary name given by the team for the object, whose official designation by the Paris-based International Astronomical Union (IAU) is 2004 XR 190. Its orbit is in a relatively narrow range of between 52 and and 62 astronomical units (AU) from the Sun (an AU is a standard measurement, being that of the distance between the Earth and the Sun, of approximately 150 million kilometers, or 93 million miles). By comparison, another "extended scattered disk" member called Sedna swings out to as far as 900 AU before coming as close to the Sun as 76 AU.
(Excerpt) Read more at physorg.com ...
I do wonder why the article calls it almost perfectly circular, since it ranges from 52 to 62 AU, about 20 per cent. The Moon is on an elliptical orbit where there's about 5 per cent difference between apocenter and pericenter. :')
If those are the elements (52x62 AU), then the eccentricity works out to about 0.08, which is resonably circular -- close enough to zero so that my toolkit of "near-circular approximations" would work just fine.
The question is, how do you get an orbit that circular with an inclination that high? It's hard to think of a "capture" scenario that would work; and it's likewise hard to think of a scenario where something huge knocked this guy out of the ecliptic plane. Either way, you'd expect to see a highly elliptical orbit -- something with an eccentricity over 0.5.
There'd have to be some long-term and regular perturbation to circularize it ... but what would it be?
:') Escape from orbit around something else? Or, it's been out there quite a while, and has had a few bumps, a brute force, monkeys and typewriters method, during encounters with other minor planets. Also, I think the article said it was an oblong piece of rock, so perhaps a very high early rotation rate altered the orbit to what is seen today (and therefore the rotation rate is low today).
Would lead to significant eccentricity with respect to the sun, probably.
Or, it's been out there quite a while, and has had a few bumps, a brute force, monkeys and typewriters method, during encounters with other minor planets.
But this is unlike other bodies in similar orbits....
Also, I think the article said it was an oblong piece of rock, so perhaps a very high early rotation rate altered the orbit to what is seen today (and therefore the rotation rate is low today).
That would probably require a long-term stay by a nearby large body, though (think about the moon's rotation, which slowed to what it is now by gravity gradient/tidal forces). Not to mention that a slowdown in rotation would not, in itself, have any bearing on the orbit of the body. The orbit and rotation would have had to have been affected by the same perturbing force.
But this is unlike other bodies in similar orbits......each of which has a unique orbit. :') Also, there are more to be discovered, and eventually this "Buffy" oddball could be known as just the first of a whole family of similar objects. That has definitely happened before.
Hi.
Please add me to your space ping list.
If that is debris from a collision or planetary explosion, there has not been time since the sun was created for the debris to spread over 100 AU.
That's certainly possible -- which is why they say its discovery raises questions about the origin of the solar system. As current theory has it, the solar system originated from a spinning ball of gas, which is why everything we know about is pretty close to the ecliptic. To find a bunch of bodies in near-circular, off-ecliptic orbits would suggest some other mechanism.
I say "near-circular" for a reason: highly elliptical bodies would be in orbits that should take them close enough to us for easy observation, and we'd probably already know about them.
"Also, the atmosphere of Jupiter is enriched in noble gases, and members of the team which discovered that suggested that it indicated an origin for Jupiter that lay past the outer planets today."
Jupiter was once a comet? Paging Cark Sagan...paging Carl Sagan...
Jupiter's Composition Throws Planet-formation Theories into DisarrayExamining four-year-old data, researchers have found significantly elevated levels of argon, krypton and xenon in Jupiter's atmosphere that may force a rethinking of theories about how the planet, and possibly the entire solar system, formed. Prevailing theories of planetary formation hold that the sun gathered itself together in the center of a pancake-shaped disk of gas and dust, then the planets begin to take shape by cleaning up the leftovers. In Jupiter's current orbit, 5 astronomical units from the sun, temperatures are too warm for the planetesimals to have trapped the noble gases. Only in the Kuiper belt -- a frigid region of the solar system more than 40 AU from the sun -- could planetesimals have trapped argon, krypton and xenon.
by Robert Roy Britt
Nov 17 1999
While lead researcher Tobias Owen does not put much stock in the idea that Jupiter might have migrated inward to its present position, other scientists on the team say the idea merits consideration. Owen expects the probes will find similarly high levels of noble gases in Saturn, Uranus and Neptune. Hints of these gases have even been found in the thick atmosphere of Venus, another planet now begging more study.
Definitely.
"Hints of these gases have even been found in the thick atmosphere of Venus, another planet now begging more study."
Finally!
I'm sure it's just a huge coincidence, or perhaps incompetence or fraud. ;')
"I'm sure it's just a huge coincidence, or perhaps incompetence or fraud. ;')"
Dr Cecilia Payne-Gaposchkin, now there's someone who could tell us...but she died in 1979. (pity, I was hoping she would live long enough to apologise.)
Speaking of coincidence, I ran across this last night whilst browsing through WIC...page 195
'In the second half of the second millenium and in the beginning of the first millenium, Venus was still a comet; and though a comet can have a circular orbit - there is such a comet in the solar system -
(The Schwassmann-Wachmann comet, the orbit of which is between the orbits of Jupiter and Saturn.)
On the Net: The Venus Tablets.
http://www.kronia.com/library/journals/ventablt.txt
One is just an extremely rare accident.
Wake me when there are two.
Coincidence?
If an object typically has an elliptical orbit of some random eccentricity, sometimes the major and minor axes just work out to be nearly equal.
Wake me when we see a statistical distribution.
Great minds think alike. I should have read to the end before posting.
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