NASA has dismissed a claim by Harvard astronomer Avi Loeb that a rare interstellar object passing through our solar system might be an alien artifact posing danger to humanity.
Loeb’s theory, published in July, suggested that Comet 3I/Atlas, set for a close encounter with Mars next month, may have been deliberately sent by an advanced civilisation.
Loeb, head of Harvard’s Galileo Project searching for signs of extraterrestrial intelligence, noted that observations of the comet so far have not shown typical features such as gaseous tails of dust and plasma that comets from within the solar system exhibit. He also pointed to the object’s unusual trajectory as evidence of “a technological artifact” with “active intelligence.”
“If future data will indicate the absence of a cometary tail, we will be faced with the tantalizing possibility that it did not inherit a random velocity in interstellar space but instead was sent towards the inner solar system by design,” Loeb wrote in a blog post.
He also raised concerns about a potential “malign intent” maneuver, stating, “The consequences, should the hypothesis turn out to be correct, could potentially be dire for humanity, and would possibly require defensive measures to be undertaken, though these might prove futile.”
However, NASA experts strongly refuted Loeb’s claims. Tom Statler, NASA’s lead scientist for solar system small bodies, stated that the object looks like a comet, performs comet-like activities, and closely resembles known comets in nearly every way. He added that while it has some unique properties not typically seen in solar system comets, its behavior is consistent with that of a comet, and the evidence overwhelmingly supports it being a natural object—a comet.
Images from the Hubble Space Telescope estimate that the comet is up to 3.5 miles (5.6 km) wide and traveling at 130,000 mph (209,000 km/h), making it the fastest visitor ever recorded in the solar system.
Statler explained that anomalies are common in comets, noting that they are composed of dust and ice and are constantly being heated by the sun, which causes changes that can be unpredictable. He added that even within our solar system, comets can suddenly brighten if a pocket of ice sublimates rapidly, releasing a large amount of dust. He further stated that such behavior is something comet observers and experts are prepared for and that it presents an opportunity to gather more information.
Statler also reassured that the comet will not approach Earth closer than about 170 million miles in the coming months. It will instead pass near Mars, Jupiter, and Venus.
He said that what makes it special is that we now have the ability to detect interstellar comets. While these comets aren’t necessarily new, it’s only recently that we’ve been able to discover them, and so far, only three have been found. This provides a window into the composition of other solar systems like never before.
Loeb himself acknowledged the comet’s natural origins. “The simplest hypothesis is that 3I/ATLAS is a comet,” he wrote, stating that his suggestions were exercises to challenge established ideas.
“Let us instead maintain our childhood curiosity and seek evidence rather than pretend to be the adults in the room that know the answers in advance,” he added.
“The hypothesis is an interesting exercise in its own right, and is fun to pursue, irrespective of its likely validity.”