Life in the Milky Way: Do Galactic Cycles Influence Earth’s Biological History?

Horoscope enthusiasts will be happy to hear that a grand cosmic force does indeed seem to be responsible for controlling the direction of all life on Earth. However, this grand cosmic cycle has more to do with extinction than finding a tall, handsome stranger.

Early last year, research revealed that the rise and fall of species on Earth seems to be driven by the undulating motions of our solar system as it travels through the Milky Way. Some scientists believe that this cosmic force may offer the answer to some of the biggest questions in our Earth’s biological history.

The University of California, Berkeley found that marine fossil records show that biodiversity increases and decreases based on a 62-million-year cycle. At least two of the Earth’s great mass extinctions-the Permian extinction 250 million years ago and the Ordovician extinction about 450 million years ago-correspond with peaks of this cycle, which can’t be explained by evolutionary theory.

Early last year, a team of researchers at the University of Kansas came up with an out-of-this-world explanation for the phenomenon. Their idea hinges upon the fact that stars move through space and sometimes rush headlong through galaxies, or approach closely enough to cause a brief cosmic tryst.

Our own star moves toward and away from the Milky Way’s center, and also up and down through the galactic plane. One complete up-and-down cycle takes 64 million years- suspiciously close to the Earth’s biodiversity cycle.

Once the researchers independently confirmed the biodiversity cycle, they then proposed a novel mechanism whereby which the Sun’s galactic travels is causing it.

Full article (and a really nice photo of the Milky Way) here:

http://www.dailygalaxy.com/my_weblog/2008/07/do-galactic-for.html