NASA And Harvard Experts Clash Over Whether Interstellar 3I/ATLAS Is 'Alien Scout' — Here's Why

When the unusual object 3I/ATLAS first entered our cosmic neighbourhood in July 2025, it didn't just appear on telescopes — it sparked a wave of speculation that shows no sign of stopping. For a brief period, the world was gripped by confusion and wonder, questioning whether we were witnessing the vanguard of an alien fleet.

The object's unusual speed and 'clean' path, which didn't have the erratic wobbling that is common in natural comets, added to the speculation. But as the visitor from another galaxy starts its long, lonely journey back into the cold depths of space, NASA and the rest of the scientific community have made a clear decision that brings us back down to Earth.

A Traveller From Beyond

The name itself, 3I/ATLAS, tells a story of being rare and being able to find things that are very new. The '3I' confirms that it is only the third interstellar object ever confirmed to pass through our solar system, following the mysterious 'Oumuamua' in 2017 and '2I/Borisov' in 2019.

The Chilean Asteroid Terrestrial-impact Last Alert System (ATLAS) first reported the visitor on July 1, 2025. 'Oumuamua was only 100 meters long, but 3I/ATLAS is a real giant. The Hubble Space Telescope recently estimated that its nucleus is up to 3.5 miles wide, making it the biggest interstellar visitor ever seen.

3I/ATLAS is a real 'outsider', unlike the comets that live in our Oort Cloud. According to calculations, this icy traveler may have been drifting through the dark for billions of years, starting from the general direction of the constellation Sagittarius.

When it was first detected, NASA clocked the visitor travelling at a staggering 137,000 mph — a speed so extreme that it confirmed the object was not bound by the sun's gravity. To put that in perspective, it is moving more than twice as fast as 'Oumuamua, a velocity that suggests it was violently ejected from a high-energy star system in the Milky Way's thick disk.

Why Avi Loeb Is 'Suspicious'

Despite the prevailing scientific consensus that we are looking at a natural comet, Harvard astrophysicist Avi Loeb has maintained a healthy level of scepticism. Loeb, famous for his provocative theories regarding 'Oumuamua, has pointed to several 'anomalies' that he claims make the object's path feel 'suspiciously' precise.

Loeb argues that the trajectory of 3I/ATLAS, which falls within just five degrees of the Earth's path around the sun (the ecliptic plane), has only a 0.2% likelihood of being a random occurrence. Furthermore, he notes that the object's route took it remarkably close to Venus, Mars and Jupiter — worlds of significant interest in our own search for life.

'It is as if the object was performing a planetary survey,' Loeb noted in a recent paper, highlighting that the object reached its closest point to the sun (perihelion) on Oct. 29, 2025, while remaining hidden behind the sun's glare from Earth's perspective — an ideal 'blind spot' for a covert probe. To Loeb, this 'fine-tuning' suggests the possibility of an artificial probe or even an 'alien mothership' that could be releasing mini-drones as it passes.

However, the broader scientific community remains unconvinced. NASA navigation engineer Davide Farnocchia has explained that the 'non-gravitational acceleration' observed is simply the result of gas and dust being expelled as the object heats up near the sun.

Additionally, a team associated with Breakthrough Listen used the massive Green Bank Telescope to listen for 'technosignatures' — the tell-tale radio frequencies of machinery. The results were absolute: there were no pings, no transmissions, and no sign of a propulsion system. The sensitivity was so high that it could have detected a transmitter with the power of a standard mobile phone at the comet's distance of 170 million miles.

A Window Into Ancient Star Systems

3I/ATLAS is an amazing find, even without the alien interest. Data from the James Webb Space Telescope (JWST) showed that the nucleus was unusually rich in carbon dioxide and nickel. This suggests that it formed in a planetary system that is much older than ours, maybe more than 7 billion years ago.

Scientists are especially confused by this high nickel-to-iron ratio because it is not often seen in local comets. Some have even suggested that the object came from a supernova-enriched environment that is very different from where our sun was born.

3I/ATLAS is already on its way back into the depths of space as it follows its hyperbolic orbit. In March 2026, it should pass the orbit of Jupiter and then disappear from view of even our best telescopes. For now, we have a lot of pictures and the knowledge that even though we may be alone in this particular encounter, the universe still has many secrets to share.