Alien Intruder? Meet 3I/ATLAS

Interstellar comet puzzles astronomers. Find out more! Photograph: Kind courtesy NASA, ESA, D. Jewitt (UCLA)/wikipedia.org/Creative Commons

3I/ATLAS is only the 3rd interstellar visitor detected in our solar system. Kind courtesy Darryl Z. Seligman et al./wikipedia.org/Creative Commons

It races through space at 26 km/second -- too fast to be captured by the Sun. Proof it came from another star system. Kind courtesy Annotated by Nrco0e. Original image by David Jewitt et al./wikipedia.org/Creative Commons

Its coma is filled with carbon dioxide, but hardly any water. Kind courtesy NASA/James Webb Space Telescope/wikipedia.org/Creative Commons

The James Webb Space Telescope spotted a huge spherical plume of CO₂ gas, stretching hundreds of thousands of km. Kind courtesy Jen Miller & Mahdi Zamani (NSF NOIRLab)/wikipedia.org/Creative Commons

Its path suggests it comes from the Milky Way's thick disk -- an ancient, metal-poor region. Kind courtesy M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar/wikipedia.org/Creative Commons

Spectra show more nickel than iron gas -- a reversal of the usual comet pattern. Kind courtesy Филипп Романов/wikipedia.org/Creative Commons

Instead of trailing behind the Sun, 3I/ATLAS shows a reverse-facing tail. Kind courtesy Nrco0e/wikipedia.org/Creative Commons

Its brightness varied strangely -- not like a normal comet. Kind courtesy International Gemini Observatory/NOIRLab/NSF/AURA/K. Meech (IfA/U. Hawaii)/wikipedia.org/Creative Commons

Despite its size, astronomers detected it late, a mystery in itself. Kind courtesy Thunkii/wikipedia.org/Creative Commons

The James Webb Space Telescope found organic cyanides like HCN. These are key building blocks of life! Kind courtesy ESO/O. Hainaut/wikipedia.org/Creative Commons

It may be billions of years old, formed before Earth existed. Kind courtesy ATLAS/University of Hawaii/NASA/wikipedia.org/Creative Commons

It's Puzzling because: • Hyper-fast speed • CO₂-driven activity • Nickel > Iron imbalance • Reverse tail • Odd light curve • Late detection • Organic cyanides Kind courtesy Tony873004/wikipedia.org/Creative Commons

3I/ATLAS challenges what we know about comets and star systems. Feature presentation: Ashish Narsale / Rediff ; Photographs curated by Manisha Kotian / Rediff Kind courtesy NASA, ESA, D. Jewitt (UCLA)/wikipedia.org/Creative Commons

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