In reply to Dwight Souder's question concerning Hale-Bopp, there are two
additional considerations affecting the comet appearance, and therein
lies the tail.
Recall that the comet starts out as a relatively compact "dirty
snowball" (or snowy dirtball) and the tail forms as water and other
volatiles are vaporized away from the sun; hence, the size of the tail is
increasing as it approachers the sun and after - until it gets far enough
away that gravitational effects exceed solar influence. Note also that
the appearance depends as well on our location relative to the comnet-sun
path. But it sure is a pretty sight! Having seen Haley's comet through
a amjor scope, this one is orders of magnitude better. It might be a
while before another like it comes around.
Larry Sacks
lsacks@cnu.edu Christopher Newport University Newport News, VA 23606