In the silent, vast space, a stellar visitor is capturing the attention of astronomers around the world: Comet 3I/ATLAS, the third interstellar object recorded by humanity. It is not another, but a millennia-old traveler that is older than the sun and could contain cryovolcanoes, a phenomenon only observed on icy worlds outside our solar system.
3I/ATLAS is moving toward Earth at a speed of 60 km per second and will make its closest approach to our planet on December 19th at about 270 million kilometers. For this reason, NASA and ESA are closely tracking its trajectory and origin. In a recent image, special telescopes discovered possible signs of internal activity, sparking even more scientific interest.
The Hubble Space Telescope captured this image of interstellar comet 3I/ATLAS on July 21, 2025, when it was 445 million kilometers from Earth.
What is 3I/ATLAS and why is it important?
The comet shows signs of eruptions that could be caused by cryovolcanoes, alien volcanoes that spew cold materials – water, ammonia or methane – instead of magma. Its age also makes it extraordinary: it is estimated to be between 7,000 and 14,000 million years old, well beyond the 4,500 million years of the solar system. Its icy, metallic surface acts as an intact record of the physical and chemical conditions of ancient star systems, making it a natural laboratory for studying the formation of planets and comets elsewhere in the galaxy.
If its cryovolcanic activity is confirmed, it would be the first interstellar comet with documented ice eruptions.
This object joins the select list of interstellar comets observed to date. In 2017, 1I/’Oumuamua and 2019 2I/Borisov were discovered, both from unknown regions and likely ejected by violent processes in their parent planetary systems.
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