Should we worry: Top experts warn over mysterious object 3I/ATLAS reaching closest to Sun on October 29

A mysterious interstellar object discovered earlier this year, 3I/ATLAS, is set to reach its closest point to the Sun (perihelion) on October 29, passing at roughly 1.36 astronomical units (AU)—similar to the orbit of Mars. Unlike typical comets, 3I/ATLAS has exhibited unusual behaviour that has captivated astronomers and sparked speculation about its true nature.

Unusual behaviour raises eyebrows

Anti-solar tail: Early observations showed gas ejecting toward the Sun, rather than away from it—a reversal of normal comet physics.

Tail reversal: By September, the anti-tail had flipped direction, further puzzling scientists.

Industrial chemical detected: Spectral analysis revealed traces of nickel tetracarbonyl, a compound not found in natural comets but used in industrial metal refining on Earth.

Interstellar origin: Its hyperbolic orbit confirms it came from beyond our solar system. Hubble observations show a teardrop-shaped dust envelope surrounding an icy nucleus estimated between 440 meters and 5.6 km wide.

Leading physicists speak out

Harvard astrophysicist Dr Avi Loeb suggested that 3I/ATLAS might not be a natural object. “If the object is an alien spacecraft slowing down, and the anti-tail is braking thrust, the transition from anti-tail to tail near perihelion would be expected,” he said. “This could represent a technosignature, indicating controlled maneuvering in the inner solar system”.

Meanwhile, Dr Michio Kaku described 3I/ATLAS as “an intelligent visitor from another solar system. If it picks up energy after the flyby, that would be definitive proof.”

NASA’s response

NASA, along with missions such as the Hubble Space Telescope, Webb, and Parker Solar Probe, is actively monitoring 3I/ATLAS. While the object’s trajectory brings it into the inner solar system, NASA confirms it poses no threat to Earth, maintaining a safe distance of approximately 270 million kilometers. Reports suggest that Earth defence systems have been quietly activated as a precaution.

What’s next

At perihelion, 3I/ATLAS will be bombarded by up to 33 gigawatts of solar radiation, which could potentially alter its speed or trajectory. Scientists are closely observing whether the object exhibits any further unusual behaviour as it slingshots around the Sun.