Asteroyid oswa kometa
Komèt Halley (1P/Halley)
The most famous periodic comet, returning about every 75 to 76 years.
NASA, ESA, CSA, STScI; J. DePasquale, A. Koekemoer, A. Pagan (STScI) (CC BY 4.0)
The first comet anyone predicted would come back, and it did.
Edmond Halley realised in 1705 that comets seen in 1531, 1607 and 1682 were the same object and predicted its return in 1758. It was the first comet recognised as periodic.
Its orbit is very eccentric (e ≈ 0.97) and retrograde. It last passed the Sun in 1986, when the ESA Giotto spacecraft flew close to its nucleus, and will return in 2061.
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