David Calder Hardy's Cosmology
Solar System Theories Challenged
December 14, 2005
ASTRONOMERS working in Canada, France and the United States said today 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, the Canada-France Ecliptic
Plane Survey (CFEPS) said.
Measuring between 500 and 1000 kilometres 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.
"This new object challenges current theories about the history of the early Solar System," CFEPS said in a statement.
"This new discovery is exciting because it causes us to rethink our understanding about how the Kuiper Belt formed."
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.
But it lies in a curious outer region of the Kuiper Belt, on the dark, bone-freezing fringes of the Solar System.
The theory is that, billions of years ago, this remote community of rocks, the so-called "extended scattered disk" of the Kuiper Belt, got their extremely eccentric orbits because of a passing star.
The star's gravitational pull was enough to give the objects a tug, pulling them out of a circular orbit but not enough to coax them away from enslavement to the Sun.
But Buffy is the odd one out - its almost-perfect orbit and tilt circular puts a dent in the "star" theory.
One possibility, the discoverers said, is that, in the infant days of the Solar System, the nascent Neptune lay much closer to the Sun.
It eventually migrated outwards, causing at least some members of the Belt's "extended scattered disk" to develop more circular and tilted orbits, they speculate.
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 kilometres).
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.
The Kuiper Belt was first recognised in 1992.
Most of its objects lie in a region that extends from 30 to 50 AU where there are "at least" 70,000 rocks with a diameter of 100 kms or more, according to David Jewitt, a specialist at the University of Hawaii (http://www.ifa.hawaii.edu/faculty/jewitt/kb.html).
Buffy was first noted by Lynne Allen of the University of British Columbia, Canada, in December last year as she pored over data from powerful computers that sift through telescopic images in search of new celestial sightings.
Because Kuiper Belt objects take so long to go around the Sun, it takes between one and two years of additional observations to calculate their orbits precisely.
Further measurements are needed over the next three months for a fine-tuning of Buffy's orbit.
Three cheers for Buffy. Little did I expect that a new planet would help with my theory of a spiralling planetary system. Well, yes, it's early days yet, but if Neptune lay much closer to the sun, one one expect that the other planets progressively did also. All the planets, including Neptune, are positioned in that Bode prediction, more or less. If Neptune was much closer to the sun billions of years ago, and the rest remained in fixed orbit there would have been chaos. I now anxiously await more data on this theory.
The report suggests that Buffy has not conformed with the characteristics of the Kuiper Belt. Whereas the Kuiper Belt appears to have been interfered with by some passing star or large object, Buffy has not. This suggests that either the Kuiper Belt has migrated to where it is now or that Buffy has migrated to where it is.
For Genesis Continuous to be right then it has to be Buffy who has spiralled out to where it is, and that the Kuiper Belt was formed billions of years before, soon after the sun became an active star as the result of solar-wind, long before Buffy migrated through it.
This scenario puts the problems with this discovery into a believable perspective. But I cannot believe that Buffy is the only one migrating. I guess that this will be confirmed later.
There is one problem with this theory and that is, if planets migrate out
and through the Kuiper belt, do they pick up some of its material? One would
think that Buffy could have a swarm of rocks and dust circling it. I wonder.
After all to spiral through it means that it is travelling faster than the
Kuiper belt and will come into proximity of a lot of rocks and dust in the
time it takes to do that. If it has swept up a ring of material perhaps that
will be discovered in the future.
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