As the comet gets closer to the sun, more jets occur until a halo of gas forms around the nucleus called the coma. Coma - The coma is a fuzzy haze surrounding the nucleus which can grow several thousand kilometers in diameter depending on the comet's distance from the sun and the size of the nucleus. As the comet approaches the sun and the Sun's wind blows more strongly, the coma starts to flow from the Nucleus and form the long tail. Tail - The tail is a fine particle trail that is dissolving off from the coma. The tail flows from the nucleus away from the sun in varying shapes and sizes and can sometime trail for millions of miles.
Comets travel in elliptical orbits and their tail usually points away from the sun.
From Tycho's observations, Kepler was able to deduce his now famous laws of motion which help explain the motion of comets and any other object that orbits. In 1994, the comet Shoemaker-Levy impacted Jupiter. Before striking Jupiter, the comet fragmented into several large chunks. Comet Shoemaker -Levy streaming toward Jupiter.