Science
What is a comet?
A comet is an icy body from the outer solar system that grows a glowing tail when it nears the Sun. As the Sun's heat vaporizes its ice, gas and dust stream off, forming a bright tail that always points away from the Sun.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains a comet.
Key things to understand
- 1It's a 'dirty snowball' of ice, dust, and rock.
- 2Most originate in the cold, distant edges of the solar system.
- 3Nearing the Sun, its ice sublimates into gas and dust.
- 4That released material forms a glowing tail, swept back by the solar wind.
- 5The tail always points away from the Sun, not behind the comet's path.
Frequently asked questions
- Why does a comet have a tail?
- The Sun's heat vaporizes the comet's ice, releasing gas and dust that the solar wind sweeps into a glowing tail pointing away from the Sun.
- What is a comet made of?
- A mix of frozen ices (water, carbon dioxide), dust, and rock — often described as a 'dirty snowball.'
- Where do comets come from?
- From the frozen outer regions of the solar system — the Kuiper Belt and the distant Oort Cloud.