A recently built telescope aimed at observing swift-moving celestial bodies has successfully recorded a comet from outside the solar system traversing the night sky prior to its detection. The NSF-DOE Vera C. Rubin Observatory located in Chile recently captured footage of the unusual interstellar guest identified as 3I/ATLAS, marking merely the third time such an object has been discovered. Astonishingly, the observatory secured the visuals 10 days ahead of NASA’s Asteroid Terrestrial-impact Last Alert System officially recognizing the comet.
In contrast to the myriad of comets that circle the sun, 3I/ATLAS is from an entirely different star system, likely propelled away by the gravitational pull of a nearby planet or a passing star. After potentially drifting for hundreds of millions of years, this massive comet, which can be seen in Rubin’s video, arrived in our solar vicinity, simply passing through.
Comets are icy, rocky entities moving through the cosmos, frequently showcasing long, brilliant trails of gas and dust as they near the sun. Over 4,000 comets have been discovered, with many additional ones possibly lurking beyond Neptune in the Kuiper Belt or the distant Oort Cloud, marking the edge of our solar system.
Differing from Halley’s Comet and others that frequently orbit the sun, 3I/ATLAS isn’t a local comet. First identified on July 1 by the ATLAS survey telescope, it was more than 400 million miles from Earth, within Jupiter’s orbit, moving at around 137,000 mph. This velocity is too rapid for the sun’s gravity to ensnare, affirming its one-way passage through the solar system.
Experts highlight that this is merely the third recognized interstellar comet. The inaugural one, a rocky, cigar-shaped object dubbed ‘Oumuamua, flew by in 2017, succeeded by 2I/Borisov in 2019, which appeared like a conventional comet. Now, 3I/ATLAS joins this exclusive category, likely the most ancient of them all.
Initial computer simulations propose that 3I/ATLAS may stem from a lesser-known sector of the Milky Way teeming with ancient, long-lived stars, possibly making it over 7 billion years old, nearly double the lifespan of our solar system. This renders it a time capsule, safeguarding materials from an earlier galactic epoch.
As it emits gas and dust while warming up, astronomers verify its icy composition, a hallmark of comets, despite sensational reports hinting it could be an extraterrestrial spacecraft. Its dusty tail might be observable from Earth with a backyard telescope later this year or in early 2026.
“While there’s *nothing wrong* with pondering whether some interstellar objects could be alien technology,” remarked Jason Wright, a professor of astronomy and astrophysics at Penn State, “3I/ATLAS has had its coma distinctly identified since July 3. It’s very clearly, *unambiguously*, a comet.”
Scientists are particularly thrilled about this finding not only due to its significance but also because of the manner in which it was discovered. The Rubin Observatory, still undergoing testing, spotted the comet before anyone was aware to search, which holds promise for future discoveries. Researchers predict Rubin could identify dozens more interstellar entities in the coming decade, potentially reaching around 50.
Interstellar bodies like 3I/ATLAS offer a direct insight into the elemental makeup of other planetary systems. Since they originated around different stars, examining them could disclose how planets develop elsewhere in the galaxy and whether the fundamental components of life traverse between stars.
At present, 3I/ATLAS is approximately 262 million miles away from Earth. It’s anticipated to make its closest encounter with the sun in late October, subsequently moving away, never to return. However, there is no cause for alarm: This comet will stay significantly distant from Earth, never coming within about 150 million miles, but leaving behind valuable information for astronomers to evaluate for years ahead.