Comets orbit around the Sun and make a giant circle pattern. This can sometimes take a few years (if they are traveling fast or maybe hundreds of thousands of years (if the orbit is very big). Astrophysicists, who study the stars and planets, track the number of comets. Through their efforts, they estimate there are over 3,500 comets out in space. But there are only about 0ne or two each year that we can see using the naked eye.