NASA Detects 'Interstellar Visitor' Hurtling Through Solar System

Astronomers have observed what they believe to be the third detected "interstellar object" speeding through the solar system in the direction of the Earth. The visiting space object is expected to depart the cosmic neighbourhood permanently after making its closest approach to the Sun in about four months, according to the National Aeronautics and Space Administration (NASA).

The comet-like body, designated 3I/ATLAS by the International Astronomical Union's Minor Planet Centre, is hurtling towards the Sun at a speed of over 60 kilometres per second and is believed to have come from interstellar space. Here, "interstellar" means the object came from outside the solar system, likely another star system. It is not bound by the Sun's gravity and is only passing through on a trajectory that shows it didn't form here and won't stay.

Originally known as A11pl3Z, the object was initially detected in data gathered between June 25 and June 29 by the Asteroid Terrestrial-impact Last Alert System (ATLAS), which uses telescopes in South Africa and Hawaii to automatically scan the night sky, Live Science reported.

With a potential 12-mile (20-kilometre) range, A11pl3Z is most likely a large asteroid or potentially a comet. It is travelling into the inner solar system at roughly 152,000 mph (245,000 km/h) and is approaching Earth from the area of the night sky where the Milky Way's bar is located.

The Minor Planet Centre (MPC), operated by the International Astronomical Union, officially designated the object as interstellar on Tuesday after analysing its trajectory and preliminary observational data.

Experts believe that A11pl3Z came from somewhere outside the gravitational pull of the Sun and has enough momentum to fly through our cosmic neighbourhood without slowing down. However, more observations are necessary to make a definitive statement.

"It looks kind of fuzzy," astronomer Peter Veres, who works for the MPC of the International Astronomical Union, told AFP.

The A11pl3Z "will fly deep through the Solar System, passing just inside the orbit of Mars," but it will have no effect on the nearby planets, Mr Veres said.

Richard Moissl, head of planetary defence at the European Space Agency, claimed that A11pl3Z is not a threat to Earth.

The object is reportedly believed to be between 10 and 20 kilometres wide, making it the largest interstellar intruder ever discovered. However, it may be smaller if the object is composed of ice, which reflects more light.

This marks the third occasion that humans have discovered something coming from the stars into the solar system.

There have only been two confirmed interstellar visitors so far.

The first one was Oumuamua, a cigar-shaped object that grabbed headlines in 2017 when some astronomers speculated that it might be an alien probe before experts determined it was most likely a space rock that shot hydrogen.

The second one was Comet 2I/Borisov, observed in 2019, as it sailed through the solar system.