A space rock surviving one of the most hostile environments in the solar system
Once every 160,000 years, a wandering traveller from the outer reaches of the solar system swings close enough to the sun to briefly rival the brilliance of Venus in our skies. This week, comet G3 ATLAS makes that ancient passage, offering humanity a rare moment of celestial wonder — provided the sun's fierce embrace does not consume it first. The comet's fate, like so much in the cosmos, remains beautifully uncertain.
- A comet discovered less than a year ago is now racing toward the sun at speeds that could make it one of the brightest naked-eye objects in nearly two decades.
- The greatest threat is the sun itself — most sungrazers are torn apart or vaporised before they ever become a spectacle, as the ill-fated Halloween Comet demonstrated just months ago.
- G3 ATLAS carries a sliver of hope: its 160,000-year orbit implies it has survived a previous solar encounter, giving astronomers cautious reason to believe it may hold together.
- The viewing window is razor-thin — peak visibility is expected around January 13th and into early next week, with Southern Hemisphere observers holding the clearest advantage.
- Northern Hemisphere stargazers must act quickly, scanning the eastern horizon before sunrise now and shifting west after sunset once the comet passes perihelion.
A comet first spotted last April, when it was still 407 million miles away, is now making its closest approach to the sun — and if it survives, it could shine as brightly as Venus, rivalling the most spectacular naked-eye comets in nearly twenty years. Known as G3 ATLAS, it will reach perihelion on January 13th, passing within less than 9 million miles of the sun.
The danger is real. Comets that venture this close are called sungrazers, and most do not endure the encounter. Just months ago, the so-called Halloween Comet — expected to be visible even in daylight — disintegrated before it could deliver on its promise. G3 ATLAS may fare better: astronomers believe its 160,000-year orbit means it has already survived at least one previous solar pass, a hopeful precedent.
Still, experts urge caution. Dr. Shyam Balaji of King's College London noted that comet brightness is notoriously unpredictable, and that local conditions will play a decisive role in whether observers can spot it at all. The comet currently sits in the Sagittarius constellation, giving Southern Hemisphere viewers a clear advantage, while those in the north face a more difficult search along the eastern horizon before dawn — or the western horizon after sunset once perihelion has passed.
The window is narrow and the outcome uncertain, but the stakes are singular: a once-in-a-lifetime encounter with a traveller that last passed through the inner solar system when our ancestors were still navigating the Ice Age.
A comet discovered last April is hurtling toward the sun at a speed that could make it one of the brightest objects visible from Earth in nearly two decades—if it survives the encounter. G3 ATLAS, formally catalogued as C/2024, was first spotted by the Asteroid Terrestrial-impact Last Alert System on April 5th when it was still 407 million miles away. Since then, it has been accelerating inward, and by this week it will reach its closest approach to the sun on January 13th, at a distance of less than 9 million miles. At that proximity, if the comet holds together, it could glow as brightly as Venus itself—a sight comparable to the "comet of the century" that astonished observers last October.
The catch is survival. Comets that pass this close to the sun are called sungrazers, and most of them don't make it. The intense heat and gravitational stress tend to tear them apart or vaporize them entirely before they ever become visible to stargazers on Earth. The Halloween Comet, which made headlines just months ago, was expected to be visible even in daylight skies. Instead, it flew too close and disintegrated. G3 ATLAS may have better odds. Astronomers have calculated that this comet takes roughly 160,000 years to complete its orbit around the sun, which means it has already made at least one close pass in its deep history—and survived it. That precedent suggests it might endure another encounter with the solar furnace.
Dr. Shyam Balaji, a researcher in astroparticle physics and cosmology at King's College London, cautioned that nothing is certain. "As with all comets, its visibility and brightness can be unpredictable," he said. "Observers may have opportunities to spot it in the days around perihelion, depending on local conditions and the comet's behaviour." He noted that viewing opportunities are notoriously uncertain and that many comets end up fainter than expected. The comet currently sits within the Sagittarius constellation, which gives observers in the Southern Hemisphere a significant advantage. Those in the north, including the UK, will face more challenging conditions.
For anyone hoping to catch a glimpse, timing and direction matter. Stargazers in the Northern Hemisphere should look toward the eastern horizon before sunrise in the coming days, watching as the comet approaches the sun. After January 13th, when it reaches perihelion and begins moving away, the view shifts: look west after sunset. But Balaji emphasized that success depends heavily on local weather, light pollution, and the comet's actual brightness once it emerges from the solar glare. The window is narrow—peak visibility is expected to last through early next week. Astronomy resources and local observatories will provide updated guidance as the date approaches, but the fundamental truth remains: this is a once-in-a-lifetime opportunity, contingent on a space rock surviving one of the most hostile environments in the solar system.
Citações Notáveis
As with all comets, its visibility and brightness can be unpredictable. Observers may have opportunities to spot it in the days around perihelion, depending on local conditions and the comet's behaviour.— Dr. Shyam Balaji, King's College London
Viewing opportunities are notoriously uncertain and many comets end up being fainter than expected.— Dr. Shyam Balaji, King's College London
A Conversa do Hearth Outra perspectiva sobre a história
Why do sungrazers so often fail to survive? What's actually happening to them?
The sun's gravity is pulling them apart, and the heat is vaporizing the ice and rock. These comets are fragile—they're mostly ice and dust held together loosely. When you get that close to a star, the tidal forces alone can shred them. The Halloween Comet didn't stand a chance.
But G3 ATLAS has made this journey before, according to the scientists. How does that change the odds?
It's the strongest argument in its favor. If it survived 160,000 years ago, it has proven it can handle the stress. But that doesn't guarantee anything. Conditions might have been different then, or it might have been larger. We're essentially betting on a comet's track record.
Why is the Southern Hemisphere getting the better view?
It's about the comet's position in the sky relative to the sun. In the south, the geometry works better—the comet will be higher above the horizon, easier to see. In the north, it's sitting low, close to where the sun is, which makes it much harder to spot without the sun washing it out.
If someone in the UK does manage to see it, what are they actually looking at?
A fuzzy patch of light with possibly a tail streaming behind it. Not a sharp point like a star. The tail forms because the sun's heat is boiling off the ice and dust, and the solar wind pushes that material away. It's one of the most beautiful things in the night sky, if you're lucky enough to see it.
What happens if it does burn up before we see it?
Then we wait another 160,000 years for the next one. That's the gamble with sungrazers. They're rare, they're unpredictable, and most of them fail. This one might too.