India, Nov 20 : In a rare celestial moment, NASA and ISRO have turned their telescopes toward the same mysterious wanderer from deep space interstellar comet 3I/ATLAS, only the third confirmed interstellar object ever observed. This cosmic visitor, passing once through our solar system and never returning, has triggered a global scientific effort spanning Earth, Mars, and multiple spacecraft scattered across the Sun’s neighbourhood.
ISRO’s breakthrough from Mount Abu
At the Physical Research Laboratory in Mount Abu, scientists used a 1.2-metre telescope to capture high-resolution images of the comet between November 12 and 15, 2025. The images revealed a bright, symmetrical coma and hints of an ion tail shaped by the solar wind. Through false-colour imaging, researchers enhanced the structure of the gas cloud surrounding the nucleus a significant milestone for India’s ground-based astronomy.
NASA transforms the solar system into an observatory
NASA, meanwhile, deployed an unprecedented fleet of 12 spacecraft and telescopes from Mars orbiters to solar probes to study the comet’s chemistry, movement, and evolution. This marks the first time NASA’s heliophysics missions and asteroid explorers have intentionally examined an interstellar object.
A rare celestial visitor
Interstellar comet 3I/ATLAS follows a hyperbolic trajectory, a clear sign that it originated from beyond our solar system. Its frozen materials, likely preserved for more than 3,500 years, contain carbon dioxide, water ice, cyanide gas, carbon monoxide, and even atomic nickel. Scientists believe it may have travelled from the Milky Way’s thick disk, making it potentially older than the Sun.
Mars provides a front-row seat
NASA’s Mars Reconnaissance Orbiter captured the clearest images yet of the interstellar comet as it passed 19 million miles from the Red Planet. MAVEN recorded ultraviolet emissions, while even the Perseverance rover managed a faint sighting from Jezero Crater.
Sun-watchers record a historic first
As 3I/ATLAS moved behind the Sun relative to Earth, NASA’s solar probes stepped in. STEREO tracked it from September 11 to October 2, SOHO observed it in late October, and NASA’s PUNCH mission captured its tail — marking the first deliberate heliophysics study of an interstellar object.
Asteroid missions join the chase
NASA’s Psyche and Lucy spacecraft, originally designed for asteroid exploration, recorded valuable data that sharpened trajectory models and revealed finer details of the comet’s coma and tail.
Hubble, Webb and SPHEREx deepen the analysis
The Hubble Space Telescope captured some of the earliest high-resolution images. Webb’s infrared instruments detected a rich carbon-dioxide signature, while SPHEREx observed the comet’s icy composition to map its cosmic origins.
Closest approach to Earth
On December 19, 2025, interstellar comet 3I/ATLAS will make its closest pass to Earth — a safe 170 million miles away. It will then drift beyond Jupiter’s orbit in early 2026, continuing its one-time journey back to the interstellar void.
Unravelling its hidden nucleus
Though the nucleus remains faint inside the glowing coma, Hubble estimates its size between 0.32 and 5.6 kilometres, with less than 1 kilometre being the most likely.
Why this interstellar comet matters
Unlike comets born around the Sun, interstellar comet 3I/ATLAS carries chemical fingerprints from another star system entirely. By comparing it with local comets, scientists hope to understand how different solar systems form, how materials evolve across galaxies, and what this means for early planetary development.
A cosmic visitor that united the scientific world
From India’s mountain observatories to Mars orbiters, from Sun-watching satellites to space telescopes, the pursuit of 3I/ATLAS has become a global scientific collaboration. For a fleeting moment, a wandering comet from another star system has brought agencies, worlds, and researchers together leaving behind a trail of knowledge that will reshape our understanding of distant cosmic origins.