Comets Unlikely to Be Source of Mass Extinctions

Reassessing the Source of Long-Period Comets

Nathan A. Kaib (1)(*)
Thomas Quinn (1)

1 Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195–1580, USA.

* To whom correspondence should be addressed.
Nathan A. Kaib , E-mail: kaib@astro.washington.edu

We present numerical simulations to model the production of observable long-period comets (LPCs) from the Oort Cloud, a vast reservoir of icy bodies surrounding the Sun. We show that inner Oort Cloud objects can penetrate Jupiter's orbit via a largely unexplored dynamical pathway, and they are a significant, if not the dominant, source of known LPCs. We use this LPC production to place observationally motivated constraints on the population and mass of the inner Oort Cloud, which are consistent with giant planet formation theory. These constraints indicate that only one comet shower producing late Eocene bombardment levels has likely occurred since the Cambrian Explosion, making these phenomena an improbable cause of additional extinction events.

hmmm. Interesting. A bit late to the jump here. Press release here.