All comets (there are over 3,500 known) have different time-scales for their appearances.
These depend on the length of their orbits - some comets have extremely large orbits which take them from being 'close' to the earth to almost going out of our solar system.
They appear because they come close enough to the Earth to be seen, and then they may take anything from a few years to hundreds of thousands of years beore they come back.
The best-known comet is Halley's Comet which has a period of between 75 and 76 years between appearances.
Edmond Halley. He stated his belief that the comet sightings of 1456, 1531, 1607, and 1682 related to the same comet, which he predicted would return in 1758. When it did it became generally known as Halley's Comet.
Gravitational pull
They come from the outer reaches of space.
It is challenging to predict which comets will be visible from Earth by 2100, as new comets are discovered regularly. However, some of the periodic comets that are expected to return within this timeframe include Comet Halley (2061), Comet Hale-Bopp (c. 4385), and Comet Swift-Tuttle (2126).
A comets orbit is considered a cycle because a comet circles back in an elliptical orbit.
Edmund Halley. He even had a comet named after him, the Halley Comet.
Edmond Halley. He stated his belief that the comet sightings of 1456, 1531, 1607, and 1682 related to the same comet, which he predicted would return in 1758. When it did it became generally known as Halley's Comet.
sir Edmond Halley was the Astronomer/Mathematician who hypothesized that the great comets that had appeared at intervals of 73 to 77 years since ancient times were all the same object, and correctly predicted its return in the late 18th Century. He didn't live to see it return, but when it did, it was named for him.
Gravitational pull
Almost all known comets follow an elliptical or circular path. This means that, over time, they return to our solar system at regular intervals. Astronomers identify each comet, and track its movement while it's in our 'neighbourhood' - then use the data to predict when it will next return.
Comets have been seen and studied by people for thousands of years. Edmond Halley predicted a comet to return in 1705 which is why we call it Halley's Comet or Comet Halley.
They come from the outer reaches of space.
There are scores of comets who's orbits have been determined, and are predicted to return, but the best known one is probably Comet Halley.
A2. There is no maximum orbiting height. Consider for a moment the comets of long return period.
It was 1682. But he didn't know it at the time. The appearance of a large comet in 1682 was an unexpected surprise to everyone, just like all cometary appearances throughout history up to that time. Halley was 26 years old. Late in his life, when he was quite accomplished at orbital calculations in addition to a lot of other things, he noticed historical records of bright comets spaced at regular intervals of between 74 and 77 years, going back centuries before the one in 1682. He proposed that comets were bound to the sun just as the planets are, that they traveled in long eccentric orbits, that the same comets might might be seen repeatedly on several visits to the inner solar system, and that the big one would return in 1758. Halley died in 1742, 16 years before his prediction could be tested. When the big one did in fact return in 1758, it began to be popularly known as Halley's Comet.
Gravity. Specifically, the gravity of the Sun.
He will be a regular until WrestleMania 27. After that, he will return to acting.