Astronomers have detected a new object hurtling through the solar system that appears to have originated from beyond our cosmic neighbourhood. The object, initially designated A11pl3Z and now known as 3I/Atlas, was first spotted on Tuesday by the Asteroid Terrestrial-impact Last Alert System (Atlas) survey telescope in Chile.
According to Nasa, subsequent analysis of data from various telescopes has extended observations back to 14 June, allowing experts to plot its trajectory. The object is currently about 416 million miles from the sun, travelling at approximately 37 miles per second relative to the sun on a highly eccentric, hyperbolic orbit. This suggests it is an interstellar visitor, similar to 'Oumuamua in 2017 and comet 2I/Borisov in 2019.
Dr Mark Norris, a senior lecturer in astronomy at the University of Central Lancashire, said: “If confirmed, it will be the third known interstellar object from outside our solar system that we have discovered, providing more evidence that such interstellar wanderers are relatively common in our galaxy.” The Minor Planet Center has reported tentative signs of cometary activity, noting a marginal coma and short tail, leading to the additional name C/2025 N1.
While some experts suggest the object could be as large as 12 miles in diameter, Nasa has stated that it poses no threat to Earth, remaining at a distance of at least 150 million miles. Colin Snodgrass, a professor of planetary astronomy at the University of Edinburgh, noted that the solid nucleus could be smaller if much of the brightness comes from the coma of dust.
The object is expected to reach its closest approach to the sun around 30 October, coming within about 130 million miles, just inside the orbit of Mars. It will then leave the solar system. Dr Norris added that it should brighten and become a relatively easy target for amateur astronomers by the time of its closest approach. Jake Foster, a Royal Observatory Greenwich astronomer, said it should be visible through a reasonably sized amateur telescope in late 2025 and early 2026.
