What is a mass of material with a long tail that travels around the sun?

A mass of material with a long tail that travels around the sun is known as a comet. Comets are composed of ice, dust, and rocky particles, and when they approach the sun, the heat causes the ice to vaporize, creating a glowing coma and a tail that points away from the sun due to solar wind. Their orbits are often highly elliptical, allowing them to travel from the outer reaches of the solar system into the inner solar system.