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Unique Conditions in Our Earth/Sun System- Part 2

Started by bstratton, 01/03/2003 05:09PM
Posted 01/03/2003 05:09PM Opening Post
Unique Conditions in Our Earth/Sun System continued:

6) The earth is just the right size for our existence. If earth were slightly larger, its gravity would be stronger and hydrogen, a light gas, would collect, being unable to escape the earth's gravity. Thus the atmosphere would be inhospitable to life. On the other hand, if our earth were slightly smaller, life-sustaining oxygen would escape and surface water would evaporate. In either case, we could not live.

7) Our planet has a large size moon. From what I have read, the gravity of our large moon helps give stability to the earth's 23.5 degree tilt axis. This helps keep surface temperatures from having wild fluctuations.

8) Jupiter seems to help clean up loose cometary debris so that it avoids colliding with earth. Having a huge gas giant like Jupiter nearby helps keep the inner solar system cleaner than it would have been from potential cometary impacts. Remember the comet Shoemaker/Levy's impact with Jupiter in 1994.

9) The sun, a G dwarf is a long lived common star. If the sun was a supergiant, then it obviously would not have lasted long before going supernova.

10) The earth is tilted 23.5 degrees. If earth were not tilted ,there would be no change of seasons. Climate would be the same all the time. While this would not make life impossible, it would make it less interesting and would drastically change the present crop cycles in many places. If the earth were tilted much more, there would be extremely hot summers and extremely cold winters. But the tilt of 23.5 degrees allows for the delightful changing of the seasons with their interesting variety.

I know there are other points I left out, and I am not a scientist so hopefully most points are up to date. These points are from a few books I have read ,plus new astronomy discoveries reported in Sky and Telescope/Astronomy magazines.