Halley's Comet, officially 1P/Halley, has begun its long journey back towards Earth after making it to aphelion - the point in its orbit farthest from the Sun - on December 9.

For Halley, that point is so far away, it extends past the orbit of Neptune.

The famous comet is slated to sling back by Earth in the year 2061. Its last visit was in 1986, when it was met with much fanfare but disappointed many - its appearance was not the imagined blazing celestial fireball, but more of a dim smudge in the sky that could not be seen with the naked eye.

But while Halley disappointed, six spacecraft from four space agencies were able to observe its structure.

Named after its discoverer, astronomer Edmond Halley, 1P/Halley completes an orbit of the Sun roughly every 75 to 79 years. This length of time earns it a designation as a "short-period" comet - which means it orbits the sun in less than 200 years.

Its short period and predictable behavior is what led to its discovery. Prior to Halley, it was not known that comets were on an orbital path that would see them return. The astronomer predicted its reappearance in 1705 based on recorded observations in intervals going back at least 2,000 years.

A sighting of 1P/Halley was even woven into the Bayeaux Tapestry - the 70-meter cloth that depicts the Battle of Hastings in 1066 and portrays the comet as large and bright.

As 1P/Halley approaches again, the possibility of a crewed mission that visits the comet - the subject of 1986 Sci-Fi classic Heart of Comet - will doubtless be debated.

Humanity has already landed a bot on a comet - the ESA's Rosetta probe reached 67P/Churyumov-Gerasimenko in 2014 before its Philae lander touched down.

We're quite good at this visiting tiny distant rocks thing now. NASA's OSIRIS-REx even took a sample from asteroid Bennu and returned it to Earth in 2023. Japan's space program has chalked up two asteroid sample return missions. Maybe by 2061 we'll be able to pay the famous comet a visit, too?

Scientists believe Halley has been around at least 16,000 years and has displayed little signs of aging. An average periodic comet completes around 1,000 trips around the Sun, according to NASA.

There's more to see from Earth that just the comet itself. Every year cometary dust from 1P/Halley creates two meteor showers: the Eta Aquariid meteor shower in May and Orionid in October.

This year's Eta Aquarii was particularly intense - with between 120 and 160 meteors visible per hour. An average meteor shower displays between 50 and 60 per hour. ®

https://www.theregister.com//2023/12/18/comet_halley_now_officially_on/