Q&A: Cosmology

Q:
Is it possible that a supernova or star birth shock waves could be one of the reasons the Earth has periodic major loss of life?

A:
That idea was carefully considered by scientists in Berkeley, California. The reasoning behind their decision that a nearby supernova was not the cause of the mass extinction 65 million years ago may be found in this article from 1979:
http://www.lbl.gov/Science-Articles/Archive/dinosaur-extinction.html

The link at the bottom of the page, "Does a companion star to the Sun cause periodic mass extinctions on Earth," will pull up a plot of the extinction rate over the age of the Earth and further information on the search for the cause of mass extinctions on our planet.