In an extraordinary scientific endeavour, NASA has mobilised a solar system-wide observation campaign of unprecedented scale to study a rare interstellar visitor. The target is comet 3I/ATLAS, only the third such object from beyond our solar system ever detected passing through our cosmic neighbourhood.
An Interstellar Visitor Under the Microscope
The comet was first spotted on July 1 by the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System) telescope located in Chile. This initial detection triggered immediate and intense interest from the global astronomical community. Shortly after its discovery, NASA's iconic Hubble Space Telescope turned its gaze towards the mysterious object.
The scrutiny intensified in August, with the powerful James Webb Space Telescope and the SPHEREx mission also capturing images. This multi-telescope approach, combining data from different instruments, provides researchers with a uniquely detailed profile. Scientists are now comparing 3I/ATLAS with comets native to our solar system, hoping to uncover fundamental differences that could reveal secrets about its origin and composition.
How to Spot Comet 3I/ATLAS from India
For astronomy enthusiasts in India and worldwide, a unique opportunity arises this month. Comet 3I/ATLAS will make its closest approach to Earth on Friday, December 19. At this point, it will be approximately 274 million kilometres away from our planet.
While this distance is nearly twice the average gap between Earth and the Sun, making it perfectly safe, it is also the best chance to observe the comet before it journeys back out of the inner solar system. To put it in perspective, at its closest, the comet will still be over 700 times farther away than the Moon.
Stargazers hoping to catch a glimpse should look towards the east to northeast in the early morning hours, just before sunrise. The comet will be positioned slightly below Regulus, the brightest star in the constellation Leo. However, spotting it will require equipment; a telescope with an aperture of 30 centimetres or more is necessary. A practical tip is to check with local observatories or astronomy clubs, as many may host special skywatching events for this celestial occasion.
An Unprecedented Coordinated Effort
NASA's campaign is truly a system-wide effort. To date, a dozen NASA instruments across various missions have already recorded and processed images of 3I/ATLAS. More observations are planned as the comet continues its journey. It is expected to pass beyond Jupiter's orbit by the spring of 2026, after which it will depart into interstellar space once again.
The coordinated observations offer a rare chance to study a single object from multiple vantage points: Earth, Mars, and space-based telescopes. Some of the most detailed shots were captured this past fall when the comet flew by Mars at a distance of about 30.6 million kilometres. Three NASA missions at the Red Planet collaborated:
- The Mars Reconnaissance Orbiter (MRO) snapped one of the closest images.
- The MAVEN orbiter collected crucial ultraviolet data to help determine the comet's chemical makeup.
- NASA's Perseverance rover managed to capture a faint image from the Martian surface, marking a rare instance of interplanetary comet observation.
By analysing this interstellar visitor and contrasting it with local comets, researchers are conducting a priceless comparative study. The findings could yield substantial clues about the formation and evolution of planetary systems across the universe, offering a glimpse into cosmic processes far beyond our own.
