Avi Loeb, a Harvard astrophysicist who has speculated that the interstellar visitor 3I/ATLAS could be artificial, says new observations show "non‑gravitational acceleration" and several anomalies. He suggests hypothetical propulsion could explain the object's blue tint and motion and notes reports of unusual chemicals and a possible metal‑alloy signature. NASA calls 3I/ATLAS a harmless comet, but Loeb urges release of Oct. 2 HiRISE images he says could clarify its nature. The object will pass about 170 million miles from Earth in late December before leaving the solar system in January.
Harvard Scientist Says Interstellar Object 3I/ATLAS Shows 'Non‑Gravitational' Acceleration — Could It Have an Engine?
Avi Loeb, a Harvard astrophysicist who has speculated that the interstellar visitor 3I/ATLAS could be artificial, says new observations show "non‑gravitational acceleration" and several anomalies. He suggests hypothetical propulsion could explain the object's blue tint and motion and notes reports of unusual chemicals and a possible metal‑alloy signature. NASA calls 3I/ATLAS a harmless comet, but Loeb urges release of Oct. 2 HiRISE images he says could clarify its nature. The object will pass about 170 million miles from Earth in late December before leaving the solar system in January.
17:13, 08.11.2025Science
Harvard Astrophysicist Raises Questions About 3I/ATLAS
(NewsNation) — Harvard astrophysicist Avi Loeb, who has previously suggested the interstellar visitor 3I/ATLAS might be artificial, says new observations reveal what he describes as "non‑gravitational acceleration" of the object as it travels through our solar system.
Put simply, Loeb is asking whether 3I/ATLAS could be "revving an engine" while passing through the inner solar system. "There was some propulsion that moved it away from its original trajectory, and I would have expected it would lose 10 to 20% of its mass as a result of the recoil," he told the program Banfield.
"When you have a visitor to your backyard, you better know its nature," Loeb said. "We can’t afford to just adopt the most likely interpretation, which is that it’s a natural object."
What Loeb Observed
Loeb has catalogued nearly a dozen anomalies in images and data collected over recent weeks. Highlights he cites include:
- A measured deviation from the trajectory expected under gravity alone ("non‑gravitational acceleration").
- An atypical blue tint when the object made a recent close pass by the Sun, which he says could stem from artificial light or, if natural, from ionized carbon monoxide.
- A reported detection of a metal‑alloy signature and unusual chemical markers.
- The absence of a typical cometary tail and an estimated size comparable to the footprint of Manhattan.
Scientific Response and Context
Many in the scientific community have pushed back on speculative interpretations. NASA, for example, describes 3I/ATLAS as a harmless comet and says it poses no threat. Loeb argues that releasing higher‑resolution data could help resolve the debate.
He has repeatedly urged NASA to release the Oct. 2 HiRISE images taken by the Mars Reconnaissance Orbiter, saying those frames could provide decisive evidence about the object's nature and that access to them has been delayed by a federal government shutdown.
3I/ATLAS — the third known interstellar object to pass through our solar system — was discovered by the Asteroid Terrestrial‑impact Last Alert System (ATLAS). It is expected to make its closest approach to Earth in late December at roughly 170 million miles before departing the solar system in January.
Note: Loeb's interpretations are speculative and contested. The broader scientific community continues to analyze observations to determine whether the object is a natural comet, a fragment of an interstellar asteroid, or something else entirely.