Did Our Sun Capture Alien Worlds?
Salt Lake City UT (SPX) Dec 01, 2004
Computer simulations show a close encounter with a passing star about 4 billion years ago may have given our solar system its abrupt edge and put small, alien worlds into distant orbits around our sun.
The study, which used a supercomputer at NASA's Jet Propulsion Laboratory in Pasadena, Calif., was published in the Dec. 2 issue of the journal Nature by physicist Ben Bromley of the University of Utah and astronomer Scott Kenyon of the Smithsonian Astrophysical Observatory in Cambridge, Mass.
Bromley and Kenyon simulated what would have happened if our sun and another star in our Milky Way galaxy had passed a relatively close 14 billion to 19 billion miles from each other a few hundred million years after our solar system formed.
At that time, our solar system was a swirling "planetary disk" of gas, dust and rocks, with planets newly formed from the smaller materials.
Imagine the encounter of two young solar systems by envisioning two circular saw blades brushing past each other while spinning rapidly. When they make contact, their outer edges are buzzed off by the other saw...cont'd
http://www.spacedaily.com/news/extrasolar-04zs.html