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Re: Asteroid impact



In a message dated 98-03-14 06:16:00 EST, wa105@mead.anglia.ac.uk writes:

<< Ray Stanford note:
 
 >    Yeah!  Not only that:  (1) This is Friday the 13th; (2) The moon is full
 >tonight; and (3) [Worse of all!] TONIGHT'S MOON WILL ECLIPSE!!!
 
 Point (2) is redundant, as every lunar eclipse occurs on the night of a full 
 moon.  For similar reasons, every solar eclipse takes place the day before a 
 new moon.  This should be obvious once you consider it. >>

Well, it's not really redundant. I think what Ray meant to say is that >not
only< is there a full moon on Friday the 13th, but it will be eclipsed. Most
full moons are not eclipsed, although of course a lunar eclipse can only occur
at the time of full moon.

Similarly, a solar eclipse can only occur at the time of new moon. Indeed, the
mid-time moment of a solar eclipse is exactly the moment of new moon, not a
day before the new moon. The first naked-eye appearance of the new moon in the
evening sky will occur a day or two after a solar eclipse, but this is not the
same thing as the moment of new moon, which is the conjunction--when the moon
and sun are closest in the sky (and the moon is invisible except during a
solar eclipse).