How many years does Halley's comet orbit the sun?

Halley's comet was the first periodic comet recorded. At the latest in 240 BC, or 466 BC, there were clear records in China, Babylon and medieval Europe, but I didn't know it was the reappearance of the same comet.

The name comes from the British physicist edmund halley (1656- 1742), who first measured its orbital data and successfully predicted the regression time. It is the only short-period comet that can be seen directly with the naked eye from the earth, and it is also the only comet that can be seen twice with the naked eye in one's life. Other comets visible to the naked eye may be more spectacular and beautiful, but those are comets that only appear once in a thousand years.

Characteristics of halley's comet.

The nucleus of Halley's comet is an ugly and dirty guy. It looks more like baked potatoes than peanuts with shells. The epidermis is covered with cracks, wrinkles and scars, and its dirty and black degree is unimaginable. Its longest length is 16 km, its mass is about 300 billion tons, and its volume is about 500 cubic kilometers.

The density of Halley's comet nucleus is very low: about 1 g/cm3, which indicates that it is porous, probably because most of the dust is left after ice sublimation. The surface of Halley's comet is darker than coal ash, which makes it absorb a lot of solar radiation and make the temperature reach 30 ~ 100℃. At least 5 ~ 7 places on the surface of the comet nucleus are constantly throwing dust and gas out.