Kathrine Frich
Human fascination with the night sky has always been driven by mystery.
From ancient star charts to modern space telescopes, unexplained objects passing through the cosmos tend to ignite equal parts curiosity and speculation.
That fascination has intensified in recent months as astronomers track a rare visitor whose behaviour does not follow familiar patterns.
A rare interstellar visitor
Scientists are closely monitoring an interstellar object known as 3I/ATLAS as it moves through the solar system and approaches its closest point to Earth.
The object was discovered in July and is only the third confirmed interstellar body ever observed entering our solar system.
Images released by the Hubble Space Telescope have documented its journey, making it a historic find regardless of its final interpretation.
Astronomers say it will pass Earth safely later this month.
Speculation and warnings
The object has attracted attention beyond the scientific community.
Avi Loeb, a theoretical physicist, has previously described 3I/ATLAS as a “potentially hostile alien threat,” a phrase that has fuelled public debate despite no evidence of danger.
Loeb’s comments have prompted renewed interest in how the object is behaving as it travels through space, particularly its unexpected changes in speed.
Strange acceleration
Recent observations suggest that 3I/ATLAS is experiencing what scientists call non-gravitational acceleration.
This means its motion cannot be explained solely by the gravitational pull of planets or stars.
Experts stress this does not imply propulsion or artificial energy. Instead, the most likely explanation involves outgassing, a common process in comets.
As frozen material heats up near the Sun, it turns directly from solid to gas, releasing jets of material that can subtly push the object and alter its trajectory.
Jets and material loss
Astronomers say 3I/ATLAS displays several comet-like features, including a tail and an anti-tail.
These are formed by jets of gas and dust escaping from the object’s nucleus and creating a surrounding cloud known as a coma.
Measurements taken from Earth and space-based telescopes indicate the object is accelerating at roughly half a micron per second squared.
While tiny, such forces can significantly affect an object’s predicted path over vast distances and time.
A recent study also suggests the nucleus of 3I/ATLAS may be around 375 metres wide, smaller than earlier estimates based on comparable objects.
Watching closely
Scientists emphasise that non-gravitational acceleration is a well-documented phenomenon and does not pose a threat to Earth.
Still, the object’s unusual characteristics make it an important case study.
As 3I/ATLAS completes its flyby, researchers hope it will provide new insights into how material formed beyond our solar system behaves once it enters our cosmic neighbourhood.
Sources: NASA, Hubble Space Telescope observations, Ladbible.
