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Jun 25, 2026
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Interstellar Comet 3I/Atlas May Be Oldest Object Seen in Our Solar System

AI Summary
Scientists believe that the interstellar comet 3I/Atlas, which passed by the sun last year, could be nearly three times older than our solar system, dating back to around 12 billion years ago. This comet is only the third visitor from beyond our solar system that has been observed. Its unusual brightness allowed for an unprecedented opportunity to study an object from elsewhere in the galaxy.

The Discovery of 3I/Atlas

An interstellar comet that blazed past the sun last year could be nearly three times older than our solar system and is unlike anything ever before seen in our cosmic back yard, astronomers said on Monday.

Unprecedented Observations

The comet 3I/Atlas is just the third visitor from beyond our solar system that humanity has ever observed, its unusual brightness offering scientists an unprecedented opportunity to study something that came from elsewhere in the galaxy.

The Age of 3I/Atlas

According to a study published in the journal Nature, 3I/Atlas could be up to 12bn years old. Our solar system is believed to have formed about 4.5bn years ago.

Chemical Composition Analysis

The new research is based on the comet’s ratio of chemical elements called isotopes detected by the James Webb space telescope and the Alma observatory in Chile. These measurements “reveal an elemental composition unlike any solar system body”, the study said.

  • The comet has 10 times more deuterium, a type of hydrogen commonly seen in heavy water.
  • This high abundance of heavy water suggests it formed in a very cold environment, likely around -243C (-405.4F).

The Impact on Astronomy

Exactly where this comet came from within the Milky Way remains a mystery, but these interstellar objects are thought to form in a similar way to the comets in our solar system – being flung out during the violent formation of a new planet.

Astronomers expect to spot many more interstellar objects in the coming years, particularly thanks to the new Vera C Rubin observatory in Chile.

The Future of Interstellar Object Research

“This is just the beginning of an exciting new field, we’ve got a lot more to learn about these things – and what they can tell us about our galaxy,” said Martin Cordiner of Nasa’s Goddard Space Flight Center.