JamulBlog

Oort clouds and evolution, oh my! Robert Zimmerman writes on his blog about a new paper in pre-print that links mass extinctions events on Earth with the Solar System's movement through the Milky Way galaxy's “arms” (the red path on their diagram at right shows the Solar System's path through the black arms of the galaxy).  The gist of their notion is that by moving through the relatively dense star population in the galaxy's arms, the Oort cloud of proto-comets is disturbed – and more of them come raining down into the inner Solar System.  Some of those strike the Earth, causing all sorts of havoc – and accelerating the rate of evolution.  Thinking about other things I've read recently, such a high rate of comet impact might also have “seeded” the early Earth with chemicals that aided life's development.