Difference between asteroids, meteors and comets, part three
A comet orbits the sun like asteroids.
However, a comet is not primarily made of rock, but contains a lot of ice and gas, which can cause amazing tails to form behind it as ice and dust evaporate.
“They range in width from a few kilometers to tens of kilometers, but as they orbit closer to the Sun they heat up, spewing gases and dust into a glowing head that can be larger than a planet,” Nasa reported.
https://www.the-sun.com/tech/5333388/nasa-asteroid-sunday-approach-updates-388945-2008-tz3/ Asteroid 388945 2008 TZ3 LIVE – ‘Potentially Dangerous Asteroid Larger Than Empire State Building’ Approaches Sunday