The Mythical Halley’s Comet Begins Its Return to the Sun and Earth

Halley’s comet

Edmond Halley, the British astronomer, published a book in 1705 proposing that the comets observed in the sky in 1531, 1607, and 1682 were, in fact, a single comet traveling in an elliptical orbit with a period of 76 years. Based on Newtonian mechanics, Halley predicted its return in 1758. Astronomers today still use the same mechanics to predict its imminent return.

On the night of December 8–9, 2023, Halley’s legendary comet will be approximately 35.14 astronomical units (5.3 billion kilometers) from the Sun, beyond Neptune’s orbit. It will not be visible to the naked eye or even in an amateur astronomer’s telescope, as it will have a magnitude of +35 in the southern constellation Hydra, the Sea Serpent.

What makes this moment special is that it marks the aphelion of Halley’s elliptical orbit. After reaching this point, the farthest from the Sun in its orbit, it will begin to approach the Sun, reaching its perihelion at 0.59 astronomical units in 2061, the closest point.

This is a notable occasion to reflect on 1P/Halley, the first periodic comet (hence the P) identified as such. Moreover, it coincides with the current trajectory of another periodic comet similar to Halley, exhibiting cryovolcanic eruptions: 12P/Pons-Brooks.

From Giotto to Rosetta

The images seen in the above video were made possible by the launch on July 2, 1985, by Ariane 1 of the European probe Giotto, named in honor of the Italian painter from the pre-Renaissance, Trecento. After eight months of travel, it approached within 600 kilometers of Halley’s Comet during the night of March 13–14, 1986, obtaining the very first close-up image of a cometary nucleus during its last periodic return to perihelion.

As we all know, this was the first time a comet and a noosphere-created object came into contact, serving as a kind of prelude to the more ambitious and spectacular Rosetta mission. Perhaps a similar event will occur around 2061, unless, of course, a mission, perhaps manned and akin to the one proposed in one of Arthur Clarke’s novels, heads towards this celestial body well before that…

As we await midnight tonight and for the weekend, one can refresh their memory or simply learn more about the comet saga, not just Halley’s, with the two videos below from the 1990s, precisely when the Rosetta mission was already being considered, but for a different comet. The landing module was not called Philae at that time but Champollion.