comet
Definition
A celestial object consisting of a nucleus of ice and dust that, when near the sun, develops a tail of gas and dust pointing away from the sun.
日本語 氷と塵の核からなり、太陽に近づくと太陽から離れた方向にガスや塵の尾を伸ばす天体。
Example
"Halley's Comet appears every 76 years."