A comet from another stellar system is currently going through our sky. His name: 3i/Atlas. This interstellar traveler fascinates astronomers around the world. Not only because it is rare, but especially because it could well be One of the oldest objects ever observed in our cosmic neighborhood.
An interstellar comet several billion years old finally enters our field of observation
On July 1, 2025, the telescopes of the Atlas network identified an unusual light in the southern sky. Quickly, astronomers dismissed the hypothesis of a classic asteroid. The speed was too high: Over 209,000 km/hwith a clearly hyperbolic trajectory. By analyzing this data, scientists understood that 3i/Atlas did not come from our solar system.
This comet would have derived during 7 to 8 billion years in the Milky Way. Over time, it has crossed stars, interstellar clouds, and suffered gravitational thrusts that have changed its trajectory. It is probably the first time that she spends near a star capable of reheating her. This unique passage triggers A gradual awakening of its frozen surfaceand offers researchers an exceptional opportunity.
Images that continue to reveal an unprecedented activity on an ice surface from another system
The Hubble space telescope captured images of the comet on July 21. What astronomers have seen exceeds expectations. A Asymmetrical coma formed around the nucleus, accompanied by a Panache of dust oriented towards the sun. A more discreet tail stretches in contrast, carried by the pressure of the solar wind.
Although the nucleus remains invisible, the data suggest that it measures less than 2.8 kilometers of radius. Dust ejection speeds vary according to their size: up to 22 m/s for the finestand much less for the biggest. This dynamic indicates a concentrated activity on specific areas of the nucleusprobably bare from their protective coat.
According to astronomer David Jewitt, this distribution of particles, with a relatively large majority of grains, would explain the modest shine tail compared to coma.
Ejected dust and water ice confirm the distant origin and the extreme age of the comet
What 3i/Atlas transports could well Go back to the origins of its original system. Indeed, ground observations have detected the presence of water iceproof that this comet still retains Primitive materials. These ice creams, released by warm -up, allow researchers to analyze their chemical composition. And therefore to go back to the initial environment in which the comet has formed.
Thus, 3i/Atlas does not just cross our sky. She hands us A direct window on a distant past, located far beyond our own star. Each observation brings one more piece to this cosmic puzzle.
And if this frozen body held, in its heart, The traces of another genesis ?