A newly discovered object hurtling through the solar system is believed to be the third known interstellar visitor from beyond our cosmic neighbourhood, according to astronomers. The object, originally designated A11pl3Z and now known as 3I/Atlas, was first spotted by the Asteroid Terrestrial-impact Last Alert System (Atlas) survey telescope in Chile on Tuesday.
Subsequent analysis of data from various telescopes has extended observations back to 14 June, allowing experts to plot its path. The object is about 416 million miles from the Sun, travelling at roughly 37 miles per second on a highly eccentric, hyperbolic orbit from the direction of the constellation Sagittarius. This trajectory suggests it is an interstellar wanderer, similar to 'Oumuamua in 2017 and comet 2I/Borisov in 2019.
Dr Mark Norris, 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, including a marginal coma and short tail, leading to the additional name C/2025 N1.
While some experts estimate the object could be up to 12 miles in diameter, NASA has confirmed it poses no threat to Earth, remaining at a distance of at least 1.6 astronomical units. Professor Colin Snodgrass of the University of Edinburgh noted that the solid nucleus is likely smaller if the brightness is partly from a coma of dust. The object will make its closest approach to the Sun around 30 October, coming within 130 million miles, before leaving the solar system.
Norris added that the object is expected to brighten as it approaches, potentially becoming visible through amateur telescopes by late 2025 and early 2026. The Virtual Telescope Project will host a live feed on its YouTube channel from 11pm UK time on Thursday.
