Comets are not “balls of ice and snow”. Comets are rocks (or piles of smaller rocks) mixed with various hydrocarbons, also ammonia (NH3), water ice, and varying traces of other things (the green comet of a year or two ago was shedding chlorine, for example).
Comets shed their gases and liquids at different rates, depending on how deep in the body they are buried, and how much energy is received from the Sun. The number of times they’re able to do that has to do with the orbit and amount of gases and liquids they have at the beginning. Eventually they shed all of it and continue on a more stable but still eccentric orbit, remaining dark. Eventually they have one or more encounters with other bodies.
Asteroids are largely known from the asteroid belt between Mars and Jupiter, but the Earth-crossers are probably the rocky remains of comets, or were shed from comets. A number of the various annual meteor showers have been associated with specific comets, and continue to travel as a debris stream in one of the old paths taken by the parent comets.
Great posting of facts. Thanks.
Good review on comets.
BTW, is that a typo in your tagline?