What do comets typically do when they near the sun?

As comets approach the Sun, they undergo significant changes due to the increase in temperature and the Sun's gravitational influence. The most notable effect is the development of tails. This occurs because the heat from the Sun causes the comet's nucleus, which is made up of ice, dust, and other materials, to start sublimating—that is, the solid material turns directly into gas. This process releases gas and dust into space, creating a glowing coma around the nucleus and often extending into one or two distinctive tails.

One tail is formed by the solar wind, consisting of charged particles emitted by the Sun, while the other is created by the pressure of sunlight on the dust particles released from the comet. These tails always point away from the Sun due to the interplay of solar wind and radiation pressure, regardless of the comet's direction of travel.

This behavior is part of what makes comets visually spectacular and distinguishes them from other celestial bodies. Their tails can stretch for millions of kilometers and are often visible from Earth, particularly when comets come close to the Sun during their orbits.