JRS: In article , dated
Sun, 2 Apr 2006 18:55:41 remote, seen in news:uk.sci.astronomy, Hayley
posted :
the amazing coincidence that the moon is exactly the right size to
exactly cover the sun about 6 times a decade to give us a spectacular
eclipse
seems almost to much to believe that it really is a coincidence,
but I cant think of anything in the evolution of the planets and the
creation of our moon
to suggest otherwise

Since the Moon's distance is steadily changing on a moderate
astronomical time-scale, there can be no astronomical reason for the
Moon being now a particular angular size.

On the other hand, therefore, the coincidence is that a more-or-less
intelligent race has evolved at the right time to see it. That's not
inevitably a complete coincidence.

If the Moon were visibly much larger, then the tides would make the
shore-line a permanent disaster area, which could prevent life moving
from sea to land. (If the Moon were much smaller, there would still be
the solar tides, which are of similar magnitude.)

If the Sun was of different absolute size, it would be of different
absolute brightness, and the zone where water is liquid would be at a
different distance. That would affect the solar tide, and so might have
significance.

All hypothetical.

--
© John Stockton, Surrey, UK. Turnpike v4.00 MIME. ©
Web URL:http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms & links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.