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First comet discovered to be periodic

First comet discovered to be periodic
Who
Halley's Comet
What
First
Where
Not Applicable
When
1705

1P/Halley, better known as Halley’s Comet, is a short-period comet that takes 75.32 years to orbit the Sun. Observations of this comet go back to at least the year 240 BCE, but it was English astronomer Edmond Halley (1656–1742) who, in 1705, first realized that sightings of this comet were actually of the same object. Halley successfully predicted its return for the year 1758.