Is 3I/ATLAS a comet or a craft? Harvard scientist says the clues are getting stranger

Representative image

A bizarre interstellar visitor sheds huge amounts of mass near the Sun, raising fresh
questions about what it really is and why its behaviour doesn’t fully match what
astronomers expect from a normal comet.

Interstellar object 3I/ATLAS has been acting stranger with every passing week. After
it skimmed past the Sun last month, astronomers noticed an enormous burst of mass
loss, the kind of shedding that usually happens when a comet is heated sharply at
perihelion.

According to a report in the New York Post, the scale of material blowing
off ATLAS is so extreme that Harvard astrophysicist Avi Loeb believes the object
might have fractured into more than a dozen pieces. He compares it to “fireworks”
released by sunlight, a natural break-up triggered by intense heating. Yet, even that
explanation doesn’t fully satisfy him.

New images that complicate the comet theory

Fresh photographs taken by British astronomers show ATLAS sporting two gigantic
jets: a 620,000-mile “anti-tail” pointed toward the Sun and a 1.8-million-mile trail
shooting the opposite way. At normal comet speeds, these jets would have needed to
fire steadily for months.

For that much mass to escape naturally, Loeb calculates that ATLAS would need an absorbing area far larger than earlier estimates, almost four times the size suggested by Hubble’s observations. To reach these numbers, he argues, the object may have fragmented into many pieces to expose more surface area.

Signals that support a natural explanation

Not all the evidence points to something exotic. On October 24, the MeerKAT radio
telescope finally detected radio absorption signatures from hydroxyl radicals, a
classic sign of water molecules breaking apart in sunlight. That would normally
strengthen the case for ATLAS being a typical comet losing water as it heats up. The
newly discovered object C/2025 V1 also hints that ATLAS might be part of an
interstellar family rather than a one-off mystery.

But the alien-technology debate refuses to die

Even with these detections, Loeb isn’t fully ruling out a technological origin. He notes
that if ATLAS somehow stays intact when it approaches Earth next month, that
would be highly unusual for a natural comet after such intense heating.

He also points out that the observed jets could theoretically be powered by thrusters rather than sublimating ice. Artificial propulsion would require far less mass loss and could easily produce higher exhaust speeds, allowing the object to maintain structural
stability.

The crucial fly-by now weeks away

On December 19, ATLAS will make its closest pass to Earth. Ground telescopes, along
with Hubble and the James Webb Space Telescope, will capture the most detailed
images yet.

If the object shows no debris, no break-up and no fading jets, Loeb says
astronomers may have to grapple with a far more provocative possibility, that ATLAS
is not a regular comet at all, but something built, not born.