ATLAS (Asteroid Terrestrial-impact Last Alert System) has discovered a new NEOCP (Near-Earth Object Confirmation Page) candidate in four 30-second survey images taken on 01 July 2025. Immediate follow up study revealed a highly eccentric, hyperbolic cometary orbit.
The comet has been named 3I/ATLAS. It originated from interstellar space. Arriving from the direction of the constellation Sagittarius, it is currently 670 million kilometres away from the Sun. It will reach its closest approach to the Sun around 30 October 2025 at a distance of 210 million km just inside the orbit of Mars.
This interstellar comet will remain at a distance of 240 million km from us hence there is no risk or threat to Earth.
The comet 3I/ATLAS provides a rare opportunity to study an interstellar object that originated outside of solar system. It is expected to remain visible to ground-based telescopes for observation through September. After this, it will pass too close to the Sun to observe. It will reappear on the other side of the Sun by early December for renewed observations.
The comet 3I/ATLAS is third interstellar object observed in the solar system.
1I/2017 U1 ‘Oumuamua was the first interstellar object observed in our solar system. It was discovered on 19 October 2017. It appeared to be a rocky, cigar-shaped object with a somewhat reddish hue behaved more like a comet.
The second interstellar object was 2I/Borisov. It was observed in our solar system in 2019.
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Sources:
- ATLAS discovers the third interstellar object, comet C/2025 N1 (3I). Posted 02 July 2025. Available at https://minorplanetcenter.net/mpec/K25/K25N12.html
- NASA Discovers Interstellar Comet Moving Through Solar System. 02 July 2025. https://science.nasa.gov/blogs/planetary-defense/2025/07/02/nasa-discovers-
- ATLAS (Asteroid Terrestrial-impact Last Alert System). Available at https://atlas.fallingstar.com/index.php
- ‘Oumuamua Overview. https://science.nasa.gov/solar-system/comets/oumuamua/
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- Comet Leonard (C/2021 A1) may become visible to the naked eye on 12 December 2021. (10 December 2021)
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