Comet or alien spaceship? World's most powerful Hubble telescope captures stunning view of 3I/ATLAS traveling at 210,000 kmph

Time of India

08-08-2025

Comet 3I/ATLAS, a rare interstellar visitor, is racing through our Solar System at record speed, offering astronomers a rare chance to study a cosmic object from beyond. Captured in striking detail by the Hubble Space Telescope, the comet shows a forward-facing dust glow and no visible gas—breaking the rules of what scientists expect from comets. Its exact origin remains a mystery, and experts believe it could be billions of years old. More answers may come from upcoming infrared observations.
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A dusty glow that defies expectation
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How big is it really?
A visitor from deep time
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Just the tip of the iceberg?
A new era in skywatching
For only the third time in recorded history, scientists are observing an object not born in our Solar System as it makes a fast, mysterious pass through. The interstellar comet known as 3I/ATLAS has just become the fastest foreign visitor ever detected, clocking speeds of 210,000 kilometres per hour.First spotted on 1 July 2025 by the ATLAS survey system when it was 675 million kilometres from the Sun, 3I/ATLAS has since drawn the attention of the world's top telescopes. On 21 July, the Hubble Space Telescope managed to capture the clearest image of the comet yet—revealing a cocoon of dust wrapped around an unseen nucleus, and, more curiously, a dust glow that appears ahead of its direction of travel.That's not how comets usually behave.Typical comets release gas and dust when heated by the Sun, forming visible tails that stream behind them. But 3I/ATLAS has flipped the script. Instead of trailing debris, the comet appears to be glowing in front of its movement, as if it's pushing a dust cloud ahead.This forward-facing plume puzzled researchers.A paper led by David Jewitt, professor of astronomy at UCLA, suggests that if 3I/ATLAS rotates slowly, its Sun-facing side could remain hot enough to release dust continuously. That dust, moving ahead due to the comet's motion and the slow spin, could create the bright front-facing coma seen in Hubble's image.The comet's rotation has been measured at 16.16 hours, and based on that rate, scientists estimate it takes about 8 hours for its hot side to turn away. During that window, the dust could travel around 10,000 kilometres—enough to explain what Hubble captured.Still, there's a catch. There's no trace of gas emissions—none of the usual suspects like CN, CO+, or neutral oxygen atoms. This was confirmed by a separate study using Chile's SOAR Telescope on 3 July, which showed reflected sunlight but no chemical signatures. The authors wrote:'The paradoxical situation of early onset coma without evidence of sublimation tracers, calls for other dust-liberating mechanisms that ancient interstellar objects may be subjected to.'The heart of 3I/ATLAS—its icy core—remains out of direct sight. But Hubble data has allowed astronomers to make an educated guess. According to The Astrophysical Journal Letters , the nucleus could be anywhere between 320 metres and 5.6 kilometres wide. That estimate is consistent with earlier predictions based on the assumption that interstellar space doesn't offer much solid material to form large objects.Upcoming observations from the James Webb Space Telescope, along with NASA's Swift Observatory and Transiting Exoplanet Survey Satellite (TESS), could offer more clarity—especially about the comet's chemical makeup.For now, 3I/ATLAS will remain visible to telescopes until September, after which it will pass too close to the Sun to be seen. If all goes to plan, it'll reappear on the far side of the Sun in early December.Everything about 3I/ATLAS points to a long and ancient journey. Scientists believe it's been drifting through interstellar space for billions of years, accelerating slightly each time it passed near stars or through star-forming regions.Its incredible speed supports this idea. As Matthew Hopkins, a recent doctoral graduate in physics from Oxford University , put it:'3I in particular is remarkable due to its velocity. This velocity is very useful to us in particular as over the last few years me and my coauthors have been building a model that allows us to predict properties of (interstellar objects) such as their age and composition, just from their velocity.'Hopkins was especially struck by the timing of its discovery—just five days after finishing his PhD research, which had focused heavily on predicting new interstellar objects.Now set to begin a postdoctoral fellowship at the University of Canterbury in New Zealand, Hopkins continues to study the comet using the Ōtautahi–Oxford model—a framework built using data from the Milky Way's stars and planet formation models.That model suggests that 3I/ATLAS has a 67% chance of being older than 7.6 billion years, far older than our 4.5-billion-year-old Sun.3I/ATLAS is only the third interstellar object ever recorded in our Solar System. The others—ʻOumuamua in 2017 and 2I/Borisov in 2019—were both unique in their own ways. And now, scientists believe there are many more slipping by unnoticed.'(Interstellar objects) actually pass through the Solar System all the time, especially the smaller ones which are more numerous: 80 the size of 'Oumuamua (about 656 feet, or 200 meters, across) pass through the orbit of Jupiter every year, they're just too small to detect unless they get very close to the Earth,' Hopkins explained in an email.But that might soon change.The newly operational Vera C. Rubin Observatory, equipped with a powerful 8.4-metre-wide mirror, is now scanning the skies every three nights. This gives it a strong chance of catching fast, faint objects like 3I/ATLAS.Hopkins and his co-authors estimate that Rubin could detect between 5 and 50 interstellar objects over the next decade. He's hopeful it'll be closer to the higher end. Each discovery brings astronomers closer to understanding the diversity—or possible similarities—among these cosmic travellers.As telescopes become more powerful, the discovery of 3I/ATLAS may signal a turning point in how we observe and understand space.'This latest interstellar tourist is one of a previously undetected population of objects bursting onto the scene that will gradually emerge,' said David Jewitt. 'This is now possible because we have powerful sky survey capabilities that we didn't have before. We've crossed a threshold.'And while 3I/ATLAS may vanish from view for a few months, the questions it raises aren't going anywhere. Where did it come from? Why does it glow ahead instead of behind? And what exactly is it made of?We don't have all the answers yet. But for the first time, we've got the tools—and the curiosity—to find out.To stay updated on the stories that are going viral follow ET Trending