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



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

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

"ScienceDaily (July 31, 2009) â 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."

The paper is:

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 V. Heinrich

P.S. although off-topic, a neat paper that appeared in Science Express is
discussed in "Extraterrestrial Platinum Was 'Stirred' Into Earth" at:

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

"ScienceDaily (Aug. 1, 2009) â 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 planetâs large-scale
convection processes."

The paper is:

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