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  Webfooted Astronomer

August 1998

How Stable Is Our Solar System?

by Laurie Moloney

August Meeting

Dr. Thomas Quinn,
Research Assistant Professor,
University of Washington

Wednesday, August 19
7:30 p.m.

A-102 Astronomy Building
University of Washington

Come early at 7 p.m. to visit
with your fellow members

Bring your slides to show
after the program

You might remember Gravity, a shareware software program from a few years ago, that let you create your own solar system. You could design a binary or triple star system and watch planets get ejected out of the solar system after a few millennia. But what would happen if you made small changes to our own solar system?

According to Dr. Thomas Quinn, research assistant professor at the University of Washington, small effects outside our solar system can cause aberrations that lead to chaotic motion, even causing some planets to be ejected from the solar system. Quinn will speak at the August Seattle Astronomical Society (SAS) meeting. He says the tilt of the Earth's spin axis is stabilized by the moon, but Mars' spin access wobbles from 0 to 60 inclination, causing severe effects on climate. Such calculations need t o be considered when calculating the probability of other stars maintaining planets in habitable zones.

SAS member Joanne Green, who has heard Dr. Quinn speak before, says, "You get a new idea of how protected the earth is by Jupiter, which attracts junk away from us, and how special is our position, how suitable for life, and how unique." The SAS meeting will be held at 7:30 p.m. on August 19 in the Astronomy Building on the University of Washington campus.

Editor's Note: For more information on the University of Washington Astronomy Department, see

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