Comet Orbit Simulator
Comets travel on long, stretched orbits that take them from the cold outer Solar System to a fast swing past the Sun. Watch them grow tails as they approach.
Why comets have tails
Far from the Sun a comet is a frozen lump of ice and dust. As it nears the Sun the ices vaporise, releasing gas and dust that form a glowing coma and two tails — a straight ion tail pushed directly away from the Sun, and a curved dust tail that trails behind the comet’s path. Both always point away from the Sun, not backward along the orbit.
Long, eccentric orbits
Comet orbits are highly eccentric ellipses, which is why some take decades or millennia to return. This is Keplerian motion at its most dramatic — see Keplerian orbits explained.