Halley’s comet

Definition

Halley's Comet is a periodic comet visible from Earth every 75-76 years. It follows an elliptical orbit around the Sun, governed by Kepler's Laws of Planetary Motion.

5 Must Know Facts For Your Next Test

1. Halley's Comet has an orbital period of approximately 75-76 years.
2. It was the first comet to be recognized as periodic by Edmond Halley in 1705.
3. The comet's orbit is highly elliptical and it spends most of its time far beyond the orbit of Neptune.
4. Kepler's Laws, particularly the third law ($T^2 \propto a^3$), can be used to calculate its orbital period based on its semi-major axis.
5. Its next perihelion (closest approach to the Sun) will occur in mid-2061.

Review Questions

• What is the approximate orbital period of Halley's Comet?
• Who was the first person to recognize Halley's Comet as periodic?
• How does Kepler's Third Law apply to calculating the orbital period of Halley's Comet?

Related terms

Kepler's First Law:

States that planets move in elliptical orbits with the Sun at one focus.

Orbital Period:

The time taken for a given object to make one complete orbit around another object.

Elliptical Orbit:

An oval-shaped path followed by an object revolving around another object, characterized by its eccentricity.