Halley

Definition

Halley refers to Halley's Comet, a periodic comet visible from Earth every 75-76 years. It is one of the most famous short-period comets known for its relatively brief return time in comparison to other comets.

5 Must Know Facts For Your Next Test

1. Halley's Comet was last visible from Earth in 1986 and will next appear in 2061.
2. Edmond Halley used Newton's laws of motion to predict the comet's return, proving that some comets orbit the sun.
3. It is classified as a short-period comet because its orbit takes less than 200 years to complete.
4. The comet's nucleus is approximately 15 kilometers long and 8 kilometers wide.
5. Halley's Comet has been observed and recorded since at least 240 BC.

Review Questions

• What significant prediction did Edmond Halley make about this comet?
• When will Halley's Comet next be visible from Earth?
• What distinguishes a short-period comet like Halley’s Comet from other types of comets?

Related terms

Edmond Halley: An astronomer who predicted the return of Halley's Comet using Newton's laws of motion.

Newton's Laws of Motion: Three fundamental principles describing the relationship between the motion of an object and the forces acting on it.

Short-Period Comet: A type of comet with an orbital period of less than 200 years, often originating from the Kuiper Belt.