
Originally Posted by
John Galt
I may be misreading the paper, but I don't see why you say the percentage drops off with distance.
Returning to the central point you make, it seems to me fundamentally flawed. In essence you appear to be making this contradictory argument.
From time to time comets appear on trajectories that reveal they have not come from interstellar space, we therefore posit a cloud of such comets around the sun some of which are disturbed by passing stars and Galactic tides so that plunge into the inner solar system. Since passing stars and Galactic tides can disturb comets they must have pretty well mashed them all out of anythin we might call the Oort cloud.
I think that is faulty reasoning, but am prepared to be persauded.
I agree no comet has been spotted with a velocity consistent with an interstellar origin, but the numbers are pretty close.
Comet west
Comet West - Wikipedia, the free encyclopedia came from a miniumum 1.1 lightyears out, assuming it was not slowed on aproach the solar system in some manner.
What are the chances of an object 1.1 lightyears out having an orbit that brings it that close to the sun, one in millions?
So how many object are there out there that have a more circular orbit?
If you assume most of the material that is orbiting the sun, is in highly excentric orbits, then these objects spend millions of years travelling slowly near aphelion, and only a few years near the sun.
As the solar system is only one billionth of the Ort cloud, the chances of true interstellar material in the cloud entering the inner solar system is very low, unless it is captured first by hitting a dense pocket of gas or something.
When you multiple all these probabilities together you still get high densities of objects at a lightyear out, and very vonerable to the tiniest external forces.
As the Sun is a larger than average star, it is likely to capture more than it loses in interactions with other stars on close approach.
I just don't see any evidence to prove the point either way.
However, if you assume every star has regular close encounters with other stars at high speed, spraying their Ort clouds in every direction, then a sea of interstellar debris looks more likely than a spherical cloud.