Hot on the tail of the Quadrantids meteor shower, another spectacle in the sky is about to arrive: comet Atlas C/2024 G3, which will reach perihelion—the point of its orbit closest to the sun—on January 13. On the same day, we will also see it at its closest point to Earth, and it could become 2025’s brightest comet, during a year in which no other comets are likely to be visible to the naked eye. Here’s everything you need to know.
C/2024 G3 was discovered on April 5, 2024, by the Asteroid Terrestrial-Impact Last Alert System (Atlas)—a network of telescopes that scans space for asteroids that could potentially hit Earth. The comet comes from the Oort Cloud, a remote region at the outer edge of the solar system that is believed to contain the remnants of the materials that formed the solar systems’s planets.
When comet C/2024 G3 reaches perihelion, it will come within just 13.5 million kilometers of the sun—for context, Mercury, the planet closest to the sun, orbits the star at a distance of 47 million kilometers. According to the latest calculations reported by the Planetary Society, C/2024 G3 could reach a brightness of magnitude –4.5, which is about the same as Venus, and is likely to be visible to the naked eye for people located in the southern hemisphere.
The comet’s unusually close journey to the sun, however, raises questions about whether it will survive. Its orbital path suggests that it is a dynamically old comet, and that this isn’t its first trip around the sun. In fact, its last approach is estimated to have been about 160,000 years ago, which means it may have already survived a close pass. “It will be very heated and may not survive,” says Nick James, director of the comet section of the British Astronomical Association. “But if it does, it could be an impressive object in the evening sky from the southern hemisphere after perihelion.”
How to Observe the Comet
Should it survive unscathed, the comet will be visible in the southern hemisphere to the west just after sunset on January 13. The comet’s orbital configuration makes it difficult to observe for those in the northern hemisphere—it will appear very low in the sky just after sunset or before sunrise, but is likely to be drowned out by twilight.
The comet’s proximity to the sun means that identifying it could be dangerous, and James says that C/2024 G3 “should only be observed if you are an experienced observer.” Looking directly at the sun without protective equipment can cause permanent eye damage.
There will also be interference from the light of the moon, which will be in its waning phases, which could make observation more difficult. Observing the comet with the naked eye in the southern hemisphere might be possible, but binoculars or a telescope might be needed.
Those who do not want to miss the show can follow the comet in images from the Solar and Heliospheric Observatory’s Lasco C3 coronagraph, or consult the IAU Minor Planet Center or the Comet OBServation (COBS) database.
This story originally appeared on WIRED Italia and has been translated from Italian.
