* Size: While some comets can be as small as one mile in diameter, others can be much larger than 500 miles. The largest known comet nucleus, C/2002 VQ94 (LINEAR), is estimated to be about 60 miles (97 km) in diameter.
* Revolving around the Sun: You are correct! Comets are celestial bodies that orbit the Sun in highly elliptical orbits.
Here's a more complete description:
Comets are icy, rocky bodies that orbit the Sun. They range in size from a few meters (yards) to several kilometers (miles) in diameter. The nucleus of a comet is the solid part, which is typically made of frozen gases, dust, and rock. When a comet gets close to the Sun, the heat causes the ice to vaporize, creating a bright coma (the cloud around the nucleus) and a tail.
Let me know if you have any more questions about comets!