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View Full Version : Discussion: Sedna Untouched for Millions of Years



Fraser
2005-Apr-13, 06:00 PM
SUMMARY: Most objects in the Solar System have been resurfaced by collisions with asteroids, smaller rocks and comets. But Sedna, on the other hand, has spent its lifetime in the remote reaches of the Solar System, and probably hasn't had many impacts at all. It's only been weathered by cosmic rays and solar ultraviolet radiation. Astronomers think that Sedna started out icy, like Pluto and Charon, but was then baked for millennia, until the ice was transformed into a complex hydrocarbon similar to asphalt.

View full article (http://www.universetoday.com/am/publish/sedna_untouched_millions.html)

What do you think about this story? Post your comments below.

antoniseb
2005-Apr-13, 06:13 PM
This is an interesting thought. Certainly most models of how Sedna came into existence suggest that it was by accretion somewhere in the region of the gas giants, but the idea that it may be little altered in the four billion years since it was ejected, except by radiation means there is a possibility for some interesting science if we ever send a probe out to it. Sedna spends most of its time outside the Heliopause, and there may be some cumulative buildup of cosmic ray debris that will tell us some tales of earlier times in our galaxy.

Gustavo 75
2005-Apr-13, 10:20 PM
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It is interesting to observe that since the discovery of Pluto and Charon no new planet was discovered in the Solar System. The distance and size of Sedna makes it invisible to amateur telescopes.
The discovery of Sedna is an astronomical feat though its existence was suspected due to the irregularities in the orbiut of Pluto. It must be no surprise to any astrnomer that Sedna's surface should be ice -rock and that the Sun would look like a distant full Moon

Hermes
2005-Apr-14, 02:51 AM
[QUOTE]Sedna might be more like the minor planet Pholus (that lies just inside the orbit of Saturn)

This surprised me. Something lurking twixt Jupiter and Saturn?. No.


5145 Pholus is located in the Kuiper Belt.

Erimus
2005-Apr-14, 06:32 AM
I wouldn't be surprised to see a push for an unmanned mission to Sedna in the next 20-30 years, especially if better deep space propulsion comes on tap.

Cave Man
2005-Apr-14, 12:21 PM
I think they're just guessing. I remember when Mars was supposed to be
the flattest planet in the Solar System.

Greg
2005-Apr-14, 04:10 PM
A minor planet between Jupiter and Saturn would be news to my ears as well. I like the idea. I guess you could say that Sedna is a super-huge comet since comets are thought to be similarly covered in baked hydrocarbons. Other KBOs would likely be coated in this fashion making them difficult to detect since this would dampen their albedo. The kind of technology needed to drill and then retrieve or analyze a core sample is probably many years away, but would generate a fabulous wealth of info on what has been happening in our vicinity regarding cosmic rays and other events. Most notably their would be a record of a large nearby grb that proportedly caused a mass extincition 350 million years ago. Before we can think of that, a mission should be sent to confirm that this is indeed the composition of its surface: ie virtually no impact craters and no geologic activity.

antoniseb
2005-Apr-14, 04:15 PM
Originally posted by Greg@Apr 14 2005, 04:10 PM
A minor planet between Jupiter and Saturn would be news to my ears as well.
Take a look at this map (the circles are the orbits of Jupiter, Saturn, Uranus, and Neptune.)

Plot of the Outer Solar System (http://cfa-www.harvard.edu/iau/lists/OuterPlot.html)

As you can see there are *many* minor planets between Jupiter and Saturn, including a few pretty big ones.