Why do comets grow tails near the Sun?

A comet’s nucleus is a mix of ice, dust, and rocky material. When it approaches the Sun, warming causes the ices to sublimate directly into gas, carrying dust with them and creating a glowing coma. Solar radiation pressure pushes dust into a curved tail, while the solar wind drives ionized gas into a straighter ion tail. This is why a comet’s tail always points away from the Sun, not behind its direction of travel.