Halley's Comet is about to begin its 38-year-long journey back towards the Sun, passing by the Earth on its way.
The Most Awaited Return
On December 8, Halley's Comet, officially known as 1P/Halley, reached its aphelion, the farthest point from the Sun. This event is something that comets typically do, but for Halley, that point is so far away that it extends past the orbit of Neptune.
During aphelion, the cosmic snowball slowed to 2,034 miles per hour (3,273 kilometers per hour). From here, it will begin its long journey back to the Sun, where it will increase its orbital velocity.
It was in 1986 when Halley's Comet made its last perihelion, or the closest point to the Sun, where it traveled at 121,572 miles per hour (195,651 kilometers per hour). During its last visit, many people were disappointed because the famous comet did not appear as the imagined blazing celestial fireball. Instead, it was seen as a dim smudge in the sky that could not be seen with the naked eye. However, six spacecraft from four space agencies were able to observe its physical structure.
The comet will not be visible to Earth until June 19, 2061, arriving at perihelion on the 28th of July that year. Halley's Comet approaches the Earth and opens the possibility of a crewed mission to visit this bolide. This is the inspiration for the 1986 sci-fi classic novel "Heart of the Comet" by David Brin and Gregory Benford. It tells the story of an ambitious manned space mission in 2061 to alter the comet's orbit to mine it for resources.
There is more to see from our perspective than the comet itself. Every year, cometary dust from 1P/Halley produced two meteor showers: the Eta Aquariid meteor shower in May and the Orionid meteor shower in October. This year's cometary dust was particularly intense for a reason. While an average meteor shower displays between 50 and 60 visible meteors per hour, Eta Aquarii displays between 120 and 160 visible meteors per hour.
Historical Records of Halley's Comet
Named after its discoverer Edmond Halley, 1P/Halley completes its journey around the Sun every 75 to 79 years. This length of time earns its designation as a "short-period" comet since it orbits the Sun in less than 200 years.
The predictable behavior and short orbital periods are responsible for discovering Halley's Comet. Before its identification, people were unaware that comets followed an orbital path. Astronomers predicted its reappearance in 1705 based on recorded observations in intervals that go back at least 2,000 years.
A significant sighting of Halley's Comet was even woven into the Bayeaux Tapestry, a 229-foot (70 meters) cloth that depicts the Battle of Hastings in 1066. In this tapestry, 1P/Halley was portrayed as large and bright.
Astronomers believe that Halley has been around for at least 16,000 years, displaying only little signs of aging. According to NASA, an average periodic comet completes about 1,000 trips around the Sun.
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