Fact-check analysisVerified as of September 27, 2025Curated by FactVerify
Mostly True

A comet named 3I/ATLAS, which is hurtling toward the inner solar system where Earth is located, is much larger than previously thought — likely weighing more than a whopping 33 billion tons, according to astronomers.

The claim that comet 3I/ATLAS is much larger than previously thought and likely weighs more than 33 billion tons is mostly true because multiple recent sources, including statements from astronomers like Avi Loeb, support this updated mass estimate, although some debate remains about its exact nature and size.

3I/ATLAS, comet hurtling toward solar system, much bigger than previously thought, astronomers say - ABC News

3I/ATLAS, comet hurtling toward solar system, much bigger than previously thought, astronomers say - ABC News

Source: abcnews.go.com

At a glance

Key Evidence

Verified September 27, 2025
The reporting

What the Evidence Shows

Recent astronomical observations and analyses indicate that the interstellar object 3I/ATLAS, which is traveling toward the inner solar system, is significantly larger and more massive than initially estimated. Several sources report that Harvard astrophysicist Avi Loeb and other researchers have suggested the object's mass could exceed 33 billion tons, a figure much higher than earlier estimates. This mass estimate has led to discussions about whether 3I/ATLAS fits the typical profile of a comet or if it might be an unusual or anomalous object.

While the scientific community generally agrees it is a comet, some researchers argue that its size and mass challenge conventional comet classifications. Additionally, the object is producing typical cometary features such as dust and ion tails as it approaches the Sun. The sources also note that 3I/ATLAS is only the third confirmed interstellar object observed entering our solar system, following 'Oumuamua and Borisov.

There is no definitive consensus on all physical characteristics, but the claim about its large mass is well-supported by multiple independent reports.

Primary trail

Verified Sources10

Interstellar Comet 3I/ATLAS is Making Its Way Closer to Earth—And New Research...

thedebrief.org
Open source

Massive comet hurtling toward solar system, much bigger than previously thought

uk.news.yahoo.com
Open source

3I/ATLAS, comet hurtling toward solar system, much bigger than previously...

abcnews.go.com
Open source
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