Fred Raslo
Harold Henderson: I gather it’s not just Upsilon Andromedae–that most of the 150-plus planets recently discovered around other stars have very elongated orbits, quite unlike the nearly circular ones we’re used to in our solar system.
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Fred Raslo: Right after a star is formed you have a disk of ingredients–soot and gases–in orbit around it. These “leftovers” gradually clump together, a bit like the way dust accumulates on the floor.
FR: Previous theorists only had this solar system to observe and explain. In the past ten years we’ve learned that the new extrasolar planets don’t fit this picture. The vast majority of these new planets do not have circular orbits; they’re highly eccentric.
HH: Meanwhile, it would be nice to have an idea why the other planetary systems seen so far aren’t like ours.
FR: It might. Basically if two planets perturb each other enough that their orbits start crossing, that’s when all hell breaks loose. And if a Neptune were to crash through here, the earth might be flung out into space, or hit another planet, or be propelled into the sun.
HH: So we may be alone out here after all.
