What is a comet tail made of?
If you condensed the entire 160-thousand-kilometre-long tail of a comet such as Hale-Bopp to the density of water, it would not even fill a swimming pool! Comet tails are made up gas and dust. These evaporate off the comet itself, which is made of ice and rock. The ice is both regular water-ice and other kinds, like carbon dioxide ice (also known as ‘dry ice’). Comets often have two tails: a ‘plasma tail’, which is made up of charged ions, and a ‘dust tail’, which is made up of dust. The lighter ions are ‘blown’ directly away from the Sun by the solar wind. The heavier dust particles form a tail that points at an angle closer to the path of the comet’s motion.
