Article: Earth's Stabilizing Moon May Be Unique Within Universe
By TAYLOR REDD - SPACE.COM
Added: Fri, 29 Jul 2011 15:42:18 UTC
This recent photo of the moon was taken by astronauts on the International Space Station during the Expedition 24 mission mid-2010. It was posted by cosmonaut Fyodor Yurchikhin of Russia's Federal Space Agency. CREDIT: Roscosmos.
New simulations show that Earth's moon is not only unique in the solar system, but may also be rare throughout the universe.
Research reveals that less than 10 percent of terrestrial planets may have a satellite large enough to provide the stability life needs to develop.
Earth spins around its orbital axis, changing its angle toward the sun — its obliquity — by a little more than a degree over the course of thousands of years. These small differences are significant enough to cause the ebb and flow of ice ages.
The moon has long been recognized as a significant stabilizer of Earth's orbital axis. Without it, astronomers have predicted that Earth's tilt could vary as much as 85 degrees. In such a scenario, the sun would swing from being directly over the equator to directly over the poles over the course of a few million years, a change which could result in dramatic climatic shifts.
Such shifts have the potential to impact the development of life.
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