Is it truly possible that this frozen traveler from another star system could be an alien spacecraft? The suggestion is tempting, but scientists tracking the interstellar comet 3I/ATLAS say the reality is not only stranger, but also far deeper, and grounded entirely in physics and chemistry.
Discovered on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on July 1, 2025, 3I/ATLAS was soon identified to be an interstellar object, the third ever detected, following in the trail of 1I/‘Oumuamua, detected in October 2017, and 2I/Borisov, detected in December 2019. Its orbit was clearly hyperbolic, indicating it was not bound to our solar system, in line with a comet, which visibly displayed characteristic behavior. It is dated between seven and eight billion years old, formed in a region orbiting an old star, well before what our own planet is. Shokhruz Kakharov, of Harvard, in collaboration with Abraham Loeb, proposed, using Monte Carlo simulation methods of possible trajectories, of 10,000 RELATED TO COMET BREAKTHROUGH Pix of a COMET cientists, of where it may have originated, indicating it likely originated within the disk region of our own Milky Way Galaxy, where older, low-metal stars abide.
While the public conjectures about alien technology were abetted by the ‘Oumuamua debates, Brian Cox and Neil deGrasse Tyson are some astrophysicists who argued against it. Cox said, “[3I/ATLAS is] a fascinating thing that current estimates say is maybe 7, 8 billion years old, has come from a distant star system older than our Solar System. An unprecedented opportunity to observe material that’s coming from a distant star system. And yet you see people going ‘it’s aliens’.” Tyson made it clear that the comet is acting like a regular comet.
As an engineering success, the observation effort was a successful celestial monitoring task. As 3I/ATLAS was discovered to be on the opposite side of the Sun from Earth, NASA launched a space agency-wide observation effort of over 20 space expeditions. Martian orbiters such as MAVEN and Mars Reconnaissance Orbiter utilized ultraviolet and visible observations from as far away as tens of millions of kilometers away and detected hydrogen emission of water ice sublimation. The James Webb Space Telescope yielded the first-ever infrared spectrum of an interstellar comet, showing an exorbitant ratio of carbon dioxide to water ice ratio, which pointed towards a more hostile radiation condition. The Hubble Space Telescope refined nucleus dimension estimations between 427 meters and 5.6 kilometers.
The spectroscopic study has also played an important role in understanding its chemical processes. ALMA observations indicated large amounts of hydrogen cyanide and methanol being emitted. The release ofmethanol outgassing at about 40 kilograms per second, of which 8% was vapor, while for solar system comets it was 2%. The presence of methanol implies that the comet has metal-rich composition and that iron compounds could have helped to produce methanol through chemical reactions involving liquid water and iron compounds. The presence of hydrogen cyanide near the core and methanol in the core and coma provides information regarding its heterogeneous nucleus.
The green color resulting from the passage of the comet out from behind the Sun is due to the solar heating, where the diatomic carbon, C₂, is released into the coma. The C₂ fluoresces through the ultraviolet heating in the near-vacuum state. The bond dissociation energy of C₂ has been recently measured in a laboratory experiment, proving the instability of the compound due to the heating from the Sun, resulting in the green color of the coma and not the tail. The cyanogen, CN, is also responsible for the color exhibited by the comet, since it has been observed that the tails of comets are typically colorless. The thermal physics consequences of the comet’s movement away from our Sun are that it will continue to warm, leading to the emission of gases from the interior of 3I/ATLAS. In comets such as 67P/Churyumov-Gerasimenko, gas emission has been observed to originate from crystallization in amorphous ice, leading to a post-outgassing phenomenon called the collapse of cometary surfaces, which occurs when the gas pressure overpowers the low tensile strength of the comet’s porous surface layers.
Whether or not such an event will occur at 3I/ATLAS when it moves away from our Sun to return to the interstellar space from where it was discovered is a question that will likely be answered before it disappears, since further observations are possible at present in a way that they For space scientists, 3I/ATLAS represents less a sign of alien landings and more a sign from the distant past of the galaxy, a natural messenger that carries physical and chemical traces from a star system that is several billion years beyond our own.
