Cosmic Scale
Halley's Comet
Periodic comet · Returns every 75–79 years
How big is Halley's Comet?
Halley's Comet is about 11.0 km across.
See Halley's Comet in 3D, at true scale
Halley's Comet is the most famous comet of all: the first known to return on a schedule, and the only bright one that does so within a human lifetime. Its dark, peanut-shaped nucleus was photographed up close by ESA's Giotto probe in 1986.
At a glance
| Diameter | 11.0 km |
|---|---|
| Mass | 2.20 × 10¹⁴ kg |
| Diameter compared with Earth | 0.001 × Earth |
| Nucleus | About 15 × 8 km |
| Orbit | 75–79 years |
| Last seen | 1986 |
| Next return | 2061 |
Good to know
- Edmond Halley predicted its return in 1758; it came back on time, 16 years after he died.
- Its nucleus is one of the darkest objects in the Solar System, reflecting only about 4% of light.
- Dust it has shed makes two meteor showers every year: the Eta Aquariids and the Orionids.