Astronomers Track Interstellar Comet 3I/ATLAS
Jul 4, 2025 by News Staff
3I/ATLAS is only the third object of its kind ever observed, following the interstellar asteroid 1I/ʻOumuamua in 2017 and the interstellar comet 2I/Borisov in 2019.
The discovery image of 3I/ATLAS from the ATLAS telescope. Image credit: University of Hawai’i.
3I/ATLAS is currently around 670 million km (420 million miles) from the Sun and will make its closest approach in October 2025, passing just inside the orbit of Mars.
It is thought to be up to 20 km (12 miles) in diameter and is traveling roughly 60 km per second (37 miles per second) relative to the Sun. It poses no danger to Earth, coming no closer than 240 million km (150 million miles) — over 1.5 times the distance between Earth and the Sun.
3I/ATLAS is an active comet; if it heats up sufficiently as it nears the Sun, it could begin to sublimate — a process in which frozen gases transform directly into vapor, carrying dust and ice particles into space to form a glowing coma and tail.
However, by the time the comet reaches its closest point to Earth, it will be hidden behind the Sun. It is expected to reappear by early December 2025, offering astronomers another window for study.
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More:
https://www.sci.news/astronomy/interstellar-comet-3i-atlas-14045.html
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