Crashing Comets Not Likely The Cause Of Earth's Mass Extinctions

Paul bristolia at yahoo.com
Sat Aug 1 10:34:54 EDT 2009

Crashing Comets Not Likely The Cause Of Earth's Mass Extinctions

ScienceDaily (July 31, 2009) — Scientists have debated how many
mass extinction events in Earth's history were triggered by a space
body crashing into the planet's surface. Most agree that an asteroid
collision 65 million years ago brought an end to the age of dinosaurs,
but there is uncertainty about how many other extinctions might have
resulted from asteroid or comet collisions with Earth.

http://www.sciencedaily.com/releases/2009/07/090730141552.htm

Kaib, N. A., and T. Quinn, 2009, Reassessing the Source of
Long-Period Comets. Published online July 30 2009,
Science Express Reports DOI: 10.1126/science.1172676

http://www.sciencemag.org/cgi/content/abstract/1172676

Yours

Paul

P.s. Additional stuff about extraterrestrial platinum can be found at:

Extraterrestrial Platinum Was 'Stirred' Into Earth

ScienceDaily (Aug. 1, 2009) — A research program aimed at
using platinum as an exploration guide for nickel has for the
first time been able to put a time scale on the planet’s large-scale
convection processes.

http://www.sciencedaily.com/releases/2009/07/090731085813.htm

Maier, W. D., S. J. Barnes, I. H. Campbell, M. L. Fiorentini,
P. Peltonen, S.-J. Barnes, and R. H. Smithies, 2009, Progressive
mixing of meteoritic veneer into the early Earth's deep mantle.
Nature. vol. 460, no. 7255, pp. 62-623.

http://www.nature.com/nature/journal/v460/n7255/full/nature08205.html