Re: Comet Tails
Look at all the posts Dan Spires proposes.
The size of a comet is extremely small (15 km for Halley and 41 km for Hale Bopp) compared to the width of the coma, even at its head. The shadow is nothing. And more, the sun's heat, in those areas, is such that outgassing does occur. Perhaps not as much in the shadow, but this doesn't matter as the nucleus rotates very fast.
Raoul