Top 5 facts about the Comet Halley.

1) Halley is often called the most famous comet, because it marked the first time astronomers understood comets could be repeat visitors to our night skies.

2) Halley was last seen in Earth's skies in 1986 and will return in 2061 on its regular 76-year journey around the Sun.

3) Halley's dimensions are about 15 by 8 kilometers, and also it is one of the darkest, or least reflective, objects in the solar system.

4) Halley's backward, or retrograde, motion is unusual among short-period comets, as its greatest distance from the Sun is beyond the orbit of Neptune.

5) With each orbit around the Sun, a comet the size of Halley loses an estimated 3 to 10 feet of material from the surface of its nucleus.