Cosmic Extinction Cause
Tools
Email Page
Print PageContact
Could the up-and-down motion of our solar system within the Milky Way cause regular die-offs?
Aired September 24, 2007
2 minutes (1.8 MB) | Download mp3
Transcript
A new theory may explain why species die off on a predictable cycle.From the University of Kansas, this is Research Matters. I'm Brendan Lynch.
Research into marine fossils proves that mass extinctions occur about every 62 million years. But science has struggled to explain why.
Now, investigators at the University of Kansas have found a likely cause by looking to the heavens. Adrian Melott, KU professor of Physics and Astronomy, says celestial motion exposes Earth to lethal cosmic rays timed to the extinctions.
Melott: "The galaxy is a thin disc kind of like a Frisbee. And the sun orbits around approximately in a circle in the plane of the Frisbee. But in addition to that, it oscillates up and down."
According to Melott, this oscillation turns deadly when the solar system climbs to the top side of the galaxy.
Melott: "Our idea is that there is a shock wave on one side of the galaxy due to its motion. This motion is not like that of a Frisbee but like a pie in the face. And we think it should produce a substantial amount of cosmic rays, which the sun and the solar system get exposed to whenever we oscillate up on the north side of that disc. "
Our solar system peaks about every 64 million years. Melott says that's in sync with the die-offs.
Melott: "Not only do these time scales appear to be almost the same but the drops in biodiversity coincide with the times when the sun is on the north side of the galactic disc. Of the big 5 mass extinctions all of them but one fit this cycle."
As Earth soaks up those cosmic rays, cancers, cataracts and mutations can result. But Melott says not to worry, there's still time to prepare.
Melott: "Move underground, take a lot of food, enough to keep you for about ten or twelve million years — that’s when the radiation should start getting bad again if our idea is right."
For more on this cosmic cause of extinctions, log on to Research Matters DOT K-U DOT E-D-U. From the University of Kansas, I'm Brendan Lynch.
Tell Me More
Looking to heavens, KU researchers solve puzzling extinctions on Earth
LAWRENCE — In 2005, University of California-Berkeley researchers Robert Rohde and Richard Muller revealed that massive die-offs occur on Earth with startling regularity — about once every 62 million years. But scientists have struggled since to pinpoint a cause for the consistently recurring extinctions uncovered in the fossil record. Now, a team of University of Kansas professors has found the likely reason by looking to the heavens.
