Do all comets have a Tail?

Tempel 1 looks so dry,and with all those sandy craters begs the question
"does it have a tail?" Some comets tails are millions of miles long,and
that could tell us something about its composition. Tempel 1 when hit
by that 600lb projectile caused a man made crater and the explosion
blaster fine dust 100 of miles into space(mostly fine dust.) Tempel 1
seen close up has proven it is not a dirty snow ball. I think when more
and more comets are probed we will have to change are way of describing
them. Comets 3.8 billion years ago were very wet. Now they are very
dry. The Sun has destroyed water molecules. into their two atoms. Its
the dense atmosphere of the Earth that has saved water from breaking
apart. Bert