A new cosmic controversy is stirring after Harvard astrophysicist Avi Loeb suggested that the mysterious interstellar object 3I/ATLAS could be made of antimatter—or possibly even represent a form of alien technology.
Writing on his blog, Loeb described antimatter as “the most efficient fuel in the universe,” arguing that if the object truly contained it, its journey through space might produce detectable gamma-ray emissions. His claim comes just days after the object’s closest approach to the Sun on October 29, which allowed researchers to gather fresh observational data.
Discovered on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii, 3I/ATLAS—also known as C/2025 N1—is only the third confirmed interstellar visitor to our Solar System, following ʻOumuamua in 2017 and 2I/Borisov in 2019.
A Visitor Like No Other
Astronomers have been fascinated by 3I/ATLAS because of its strange behavior and unusual appearance.
According to NASA’s data, as the object passed within 172 million miles of the Sun, it exhibited:
| Observed Feature | Possible Explanation |
|---|---|
| Rapid brightening | Sublimation of frozen materials or internal energy release |
| Non-gravitational acceleration | Outgassing or possible propulsion-like behavior |
| Blue coloration | Unique surface composition, possibly metallic or icy |
Loeb highlighted that the comet’s non-gravitational acceleration could hint at something beyond natural explanations. In his words:
“Alternatively, the non-gravitational acceleration might be the technological signature of an internal engine.”
He also pointed out that 3I/ATLAS’s trajectory is aligned within just five degrees of the ecliptic plane, a coincidence that he said has only a 0.2% probability of occurring naturally. Such alignment, he believes, could suggest intentional navigation rather than random cosmic travel.
Adding to the intrigue, the object’s color appeared “bluer than the Sun” during its solar approach—a trait rarely seen in typical comets or asteroids.
Divided Reactions in the Scientific Community
Not everyone shares Loeb’s enthusiasm for unconventional explanations. Many astronomers have responded with caution, warning that extraordinary claims require extraordinary evidence.
Dr. Samantha Lawler, an astrophysicist at the University of Regina, told EarthSky:
“Extraordinary claims require extraordinary evidence, and the evidence presented is absolutely not extraordinary.”
Officials from NASA also downplayed Loeb’s interpretation, stating that the object “behaves like a natural comet in all observable ways.” According to their findings, the observed acceleration and brightening can be fully explained by normal outgassing as the object warms near the Sun.
Cosmologists have similarly dismissed the antimatter hypothesis, pointing out that any significant amount of antimatter would interact with regular matter, producing detectable gamma rays throughout the universe. So far, no such emissions have been observed from 3I/ATLAS.
Even Loeb acknowledges the theoretical difficulty, admitting that large antimatter bodies “should have been destroyed soon after the Big Bang.” Still, he argues that the object’s unusual data make it worthy of deeper investigation.
Loeb’s Broader Argument
This isn’t the first time Avi Loeb has challenged mainstream scientific thinking. In 2018, he famously proposed that ʻOumuamua—the first interstellar object ever detected—could have been an alien probe powered by light sail technology. That claim sparked widespread debate and criticism but also inspired new research into nontraditional astrophysical models.
For Loeb, 3I/ATLAS represents another opportunity to push the boundaries of conventional understanding. In a recent interview, he said:
“The implications of alien technology would be immense, and we must seriously consider this possibility.”
Loeb argues that science progresses through curiosity and skepticism, not dismissal. He continues to collect data from observatories around the world and encourages other researchers to remain open-minded about 3I/ATLAS’s origin.
A Continuing Mystery
Whether 3I/ATLAS turns out to be a rare natural comet or something far more unusual, its discovery has already deepened our understanding of interstellar visitors. As telescopes capture more detailed images and spectroscopic data in the coming weeks, scientists hope to determine what drives the object’s strange motion and vivid color.
For now, the debate continues between those seeking natural explanations and those, like Loeb, who believe something extraordinary may be crossing our cosmic neighborhood once again.
References:
- IBTimes UK – Harvard Astrophysicist Suggests Interstellar Object Could Be Antimatter
- Futurism – Rare Interstellar Comet 3I/ATLAS Stuns Astronomers With Unusual Orbit
- Science Times – Astronomers Debate 3I/ATLAS Behavior
- The Economic Times – Avi Loeb’s Antimatter Hypothesis Sparks Reactions
- The Guardian – NASA Officials Respond to Antimatter Claims
