Interstellar Interlopers, Coming in from the great beyond |
Interstellar Interlopers, Coming in from the great beyond |
Oct 27 2017, 01:40 PM
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#1
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Member Group: Members Posts: 541 Joined: 17-November 05 From: Oklahoma Member No.: 557 |
They finally found a chunk of something coming into the Solar System. Something much bigger than cosmic rays or dust particles.
Asteroid/comet in hyperbolic trajectory |
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Nov 4 2017, 08:50 AM
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#2
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
The paper I mentioned above says at the end of page 1, that there is a discrepancy between the expected residence time of 2.5 Gyrs of a dust grain in the ISM and the expected lifetime of 0.5 Gyrs of a dust grain. Then they try to overcome this discrepancy by grain growth in cold molecular clouds (subsection 4.2):
QUOTE The only possible site of grain growth in the ISM are the dense molecular clouds of the cold phase of the ISM (Draine 1990). With the presence of interstellar comets and asteroids, I'm not sure, whether this conclusion is evident, since new grains could also form by collisions of small dust grains with these larger bodies, such that we should get a secondary population of interstellar dust grains made of debris, possibly statistically comoving with the (rogue) asteroids and comets. If this turns out to be realistic, we should get information about "interstellar interlopers" by the analysis of interstellar dust. Since there may exist many such unbound small bodies, some useful result regarding an origin could only be obtained, if these small bodies form themselves a more or less comoving cloud, inducing such a co-motion into the according presumed debris made of interstellar dust. |
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