The composition of comets

摘要: Questions concerning the origin of comets are considered. It is pointed out that molecular composition a dense interstellar cloud appears to have exactly needed produce observed features visible cometary spectrum, which consists mainly emission bands unstable free radicals. A working model structure discussed together with classical observations led it. The was originally described by Whipple (1951). emphasized can serve only as rough guide in efforts interpret evolution behavior. survey provided new techniques recently been applied observations, taking into account spectrum comet, radio and ultraviolet observations.