In January of 2025, we were given the opportunity of a lifetime – to see a rare and newly discovered comet during the day – and without the need for special apparatus or telescopes. A new comet lit up in the skies, illuminating a trail behind it for over a week as stargazers all over the world looked up to see the rare and magnificent event. It was a jaw-dropping event, an old-period comet reaching its perihelion – the closest point to the sun – and burning our skies, and a rarity not lost on astronomers. Though it was only viewable by the naked eye for a mere few days, the event has undoubtedly garnered great interest and will be studied for many years to come.
The comet in question, Comet C/2024 G3, was only discovered half a year prior to the astronomical event, and its great outburst has been described as a one in a 160,000-year event. People in the Southern Hemisphere, from South America to Southern Europe and Australia, caught the best sightings of what is now defined as a significant astronomical spectacle.
Discovery of Comet C/2024 G3 Atlas
The comet was discovered in April 2024 by the Asteroid Terretrial-impact Last Alert System (ATLAS).ATLAS was specifically developed to spot comets or small celestial bodies that approach Earth. It is a defence system that helps scientists discern any threats to Earth or any celestial body that could possibly come into the Earth’s orbit and impact Earth.
ATLAS caught images of the comet, which at the time was around 4.38 AU, or 655 million kilometres, from Earth. When the comet was spotted, astronomers initially theorised that it could be from the Oort cloud. The vast cloud is thought to be filled with icy planetesimals, surrounding our Sun at a distance of 0.03 to 3.2 light years. It produces countless long-period comets that enter the inner Solar System, where they orbit until getting consumed and destroyed as they approach the Sun.
Though, after more information about Comet C/2024 G3 became available, scientists then changed their hypothesis, believing this could be a dynamically old comet that had made previous approaches to the Sun.
Timing and Visibility of the Comet Outburst
By the middle of December 2024, the comet had brightened and was located in Scorpius, in the Southern celestial hemisphere. The comet experienced an outburst in January, reaching a magnitude of -3.8, making it the brightest comet of 2025. From January 3rd, Comet C/2024 G3 became marginally visible, but by the 11th, it reached its brightest.
From January 11th to the 19th, the comet entered its peak brightness and even became bright enough to photograph in daylight. It became the 5th comet in the last 100 years to have been observed in daylight.
Similar Astronomical Phenomenal
Comet C/2024 G3’s outburst was a large event and one of the least common in our recorded history. The last similar event was back in 2007, that of Comet McNaught, or C/2006 P1 making a similarly large tail in the sky. Another name for this non-periodic comet is the Great Comet of 2007. Robert H. McNaught discovered it via the Uppsala Southern Schmidt Telescope. It attained a peak magnitude of -5.5, greatly outperforming Comet C/2024 G3, which reached an apparent peak magnitude of -3.8. Coincidentally, the latter comet also reached perihelion in January and was primarily visible in the Southern Hemisphere.
The only other comets of this kind that have been recorded in recent astronomical history are Comet Ikeya-Seki of 1965 and, before that, the Great Comet of 1910. To learn about the dynamics of old comets from the Oort Cloud as they traverse our observation window, analysing C/2024 G3 against previous occurrences is crucial.
Where is Comet C/2024 G3 Now
The comet has since passed beyond the Sun’s perihelion and is thus no longer visible. The comet faded to magnitude 2 in February and was no longer visible during the day.
Astronomers and researchers predict that Comet C/2024 G3 will not be seen again for hundreds of thousands of years in the future. Even so, this display, along with other similarly comparable astronomical events, is priceless for what is revealed about long-period comets and their interaction with the sun. Those who get to see the comet in person will remember it as a very spectacular celestial phenomenon and probably a once-in-a-lifetime experience.