Physical Properties
Orbit
Sources & Further Reading
- NASA — official mission / factsheet page
- Wikipedia — extensive cross-referenced article
- NASA u2014 1P/Halley
- ESA Giotto Mission
Numerical values (radius, mass, orbital elements, temperatures) are drawn from NASA NSSDC Planetary Fact Sheets, JPL Horizons, and the JPL Small-Body Database. Last refreshed: 2026-04-18 18:19:27.
1P/Halley is the most famous comet, observed by civilizations since at least 240 BCE and the first object ever recognized as a periodic comet. English astronomer Edmond Halley predicted in 1705 that the comets seen in 1531, 1607 and 1682 were the same object returning every ~76 years, and its recovery in 1758 (16 years after his death) confirmed the prediction. Halley was the first comet to be imaged up close: during its 1986 apparition, the Soviet Vega 1 & 2, Japanese Sakigake & Suisei, and ESA’s Giotto all flew past the nucleus. Giotto passed within 596 km and revealed a dark, 15 × 8 × 8 km potato-shaped nucleus emitting jets of gas and dust on the sunward side.