A Comet Is Going to Execute a Once-in-a-Lifetime Magic Trick: It's Set to Happen Between Now and October

On Jan. 9, 2023, researchers at the Purple Mountain Observatory in China discovered something extraordinary–a unique comet coming from the Oort cloud. However, after a few weeks, its trail was lost. Finally, on February 22, 2023, the comet was identified again from ATLAS in South Africa and named C/2023 A3 (Tsuchinshan-ATLAS). This comet has unusual characteristics that make it shine brighter than some stars. Pretty soon, we'll be able to see the comet in all of its splendor and as in a spectacular astronomical event.

The brightest comet. The comet’s perihelion, or its closest approach to the Sun, will be on Sept. 28, 2024, before reaching its closest point to Earth a few weeks later, around Oct. 12 or 13. According to astronomers, the comet’s brightness is predicted to have a magnitude 0.7 at perihelion. Lower magnitudes on the scale indicate brighter objects. For instance, Betelgeuse in the constellation Orion is about 0.42, and Antares, the brightest star in Scorpius, is a little above 1. Therefore, we're set to witness a very special celestial body.

Visible to the naked eye. Some astronomers even predict that the comet could reach a brightness of magnitude 0 at the time of its closest approach to Earth on Oct. 12 or 13. If this happens, it’ll be brighter than most stars and easily visible to the naked eye worldwide, without the need for telescopes or other equipment. This should also allow it to develop an impressive comet tail and offer incredible photo opportunities.

What will happen at the closest point to Earth? At that point, the magnitude of the comet could reach as much as -0.2, making it one of the brightest objects in the night sky. Additionally, the comet’s dust and ice will reflect the light from the Sun, leading to a phenomenon called “forward scattering.” This could cause the comet to shine as brightly as Venus, with a magnitude of between -0.7 and -5.

Current status. At the moment, the comet is hurtling towards Earth at a speed of approximately 112,225 m/ph (180,610 km/h). If everything goes as predicted, the comet—which last passed Earth about 80,000 years ago—will become visible to the naked eye in this October.

However, it’s important to note that these predictions are subject to change, which is why we can’t give you an exact time or date. Why? The comet will have to “face” the Sun and survive its powerful rays at its perihelion.

Behind the name. In case you’re wondering why comets are named the way they are, here’s the answer. The letter “C” is used for comets with an open trajectory that escapes the Sun’s orbit. “2023” is the year of its discovery, while “A3” refers to the fact that it was the third discovery in the first fortnight of January. This way, “B” would represent the second fortnight, and so on.

Image | John Vermette | Dominique Dierick