How do comets grow tails near the Sun?

Comets are often described as dirty snowballs because they contain ice, dust, and rocky material. When a comet approaches the Sun, its surface warms and volatile ices sublimate, meaning they change directly from solid to gas. This outgassing releases dust that forms a bright, curved dust tail, while charged particles create a straighter ion tail. The tails can become millions of kilometers long, even though the nucleus itself is often only a few kilometers across. Comet tails are a dramatic example of how sunlight and solar wind interact with small bodies in the Solar System.