Abraham “Avi” Loeb, the Harvard astronomy professor and bestselling author, has dared to explore what he calls “the most romantic question in science”: Are we alone?
“This question is a question that every lonely person asks,” Loeb said in an interview at his Lexington home. Too often, he said, humans become preoccupied with what happens close to us, in our home on the cosmic block. But Loeb looks beyond.
Loeb has caught the public’s – and NASA’s – attention for his comments about a newly discovered interstellar object, known as 3I/ATLAS, that is hurtling toward the sun and through our solar system. NASA says it’s a comet. Loeb suggests it could be alien technology.
“What I’m doing as an astrophysicist is looking at nature on the biggest stage, which is the universe,” he said.
Loeb, 63, has had a long and distinguished career. He’s written nine books and has been the longest-serving chair of Harvard’s astronomy department. He has long been interested in exploring the potential of alien life. Loeb has gained the critical and curious eye of the scientific community and the public for his commentaries and papers delving into the possibility of interstellar objects being alien technology – specifically in the case of 3I/ATLAS.
“We have the duty to consider a low probability event, just because the implications are huge.” Abraham ‘Ari’ Loeb, Harvard astronomer
The comet 3I/ATLAS – which is headed toward the center of the solar system and expected to reach its closest proximity to the sun Oct. 29 – holds the record for the highest velocity ever recorded of an interstellar object, at 130,000 miles per hour, according to NASA’s reports from August 2025. Loeb cited anomalies in the trajectory of the object as evidence of the potential of alien technology.
Loeb reached into a bowl of seashells decoratively placed on his living room table, arranging a few in the shape of the Sun, Mars and Earth. One seashell remained in his hand to serve as 3I/ATLAS, moving around the others to show the path the object had followed.
Loeb said 3I/ATLAS “is probably a natural object” but thinks it’s important to consider the possibility that it’s technological.
“We have the duty to consider a low probability event,” Loeb said, “just because the implications are huge.”
NASA has disputed Loeb’s ideas that 3I/ATLAS is anything other than a comet, but that has not slowed him from exploring the topic through regular commentaries on his Medium page. Since the discovery of 3I/ATLAS on July 1, Loeb has rarely missed a day posting on his blog. He covers the new astronomical discoveries, the impacts they have for humanity and occasionally advice on how to respond to potential alien interaction.
“What I write there is what I believe in,” Loeb said. “And sometimes, you know, it may not be right in retrospect, but that’s what I believe at the time that I’m writing it. And people connect to that.” He said he wants to encourage younger people to be curious – about both the known and unknown.
Tony Pan, a former graduate student of Loeb’s who went on to found his own clean technology business called Modern Hydrogen, said that until meeting Loeb he found academia to be unfriendly. Loeb, however, was both creative and good at holding himself accountable to testable predictions, Pan said.
“It takes a lot of creativity to stick your neck out, and most creative predictions will be wrong,” Pan said. “Avi warned of that too. When you work on the frontier, a lot of your predictions will be wrong.”
Many people have expressed skepticism of Loeb and his scientific commentary. The social media forum Reddit contains pages dedicated to discussing Loeb. A YouTube channel called “Professor Dave Explains” – with upwards of 4 million subscribers – calls Loeb a fraud.
Loeb said science, to him, is “preserving what is left of your childhood curiosity.” He worries that scientists are motivated by the wrong reasons – to impress their peers – and that will rub off on the younger generation of people trying to break into scientific and academic fields. Loeb said he rarely regrets what he says.
Every day at sunrise, he jogs 3 miles. He said he enjoys the company of wild turkeys, bunnies and ducks, and that Lexington serves as a good reminder of where he came from: a small farm in Israel, where he became enraptured by philosophy. He recalled sitting on the tractor, reading late into the day. Now, he is the father of two daughters.
“He loves to talk about everything,” said daughter Lotem Liviatan Loeb, a junior at Harvard College studying neuroscience and physics. “You’d think that his interests are isolated to astrophysics, but they really aren’t.”
Lotem Loeb recalled walks with her father throughout her life, where he would point to plants and talk extensively about each. She attributes most of her appreciation of the natural world to her father.
“He’s received a lot of backlash recently,” she said. “But at his core he’s just trying to be the scientist and curious person that he feels society needs him to be.”
This story is part of a partnership between Cambridge Day and the Boston University Department of Journalism.
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