An extraordinary show currently takes place in our solar system. 3i/Atlas, a giant comet from interstellar depths, offers astronomers an unprecedented bright show while spinning towards the sun at a dizzying speed of 210,000 km/h. This cosmic traveler, discovered only a few weeks ago, could well be the oldest comet ever observed.
A cosmic intruder with exceptional dimensions
On July 1, astronomers spotted an unusual object crossing our cosmic neighborhood. In less than 24 hours, NASA confirmed the incredible: it was an interstellar visitor, a fragment ejected by a distant stellar system which now crosses our area of space. With a diameter of up to 24 kilometers, 3i/Atlas far exceeds its predecessors in size and speed.
This discovery marks a historic moment in modern astronomy. Only two other objects of this type were previously confirmed: the enigmatic 1i/’Oumuamua in 2017 and the Comète 2i/Borisov in 2019. But 3i/Atlas is distinguished by its exceptional characteristics and its mysterious origin in a region completely different from the Milky Way.
A cosmic fossil of billions of years
The first analyzes suggest that this comet could be up to 3 billion years older than our solar system. This extraordinary antiquity potentially makes a real cosmic fossil, witness to the early days of galactic training. Imagine: this ice cream and rock ball has traveled in interstellar space for billions of years before reaching our solar system.
This exceptional longevity offers scientists a unique opportunity to study the composition and characteristics of an object preserved in the freezing cold of the interstellar space for eons. Each observation could reveal precious clues to the conditions which reigned in our galaxy long before the birth of the sun.
A light show captured by the telescopes
The astronomers of the Gemini North telescope, perched at the top of the Mauna Kea volcano in Hawaii, followed 3i/Atlas carefully since its discovery. Their observations have produced absolutely striking images, including an accelerated sequence where the comet appears as a collar of cosmic pearls oscillating between blue, red and green.
This colorful illusion results from the use of different photographic filters combined in a single image. In reality, the comet emits white light, but this technique reveals the hidden beauty of its displacement in space. Astronomers have also captured fascinating details of its hair, this cloud of ice, gas and dust which envelops the frozen core of the comet.
The colors of the new image are the result of different filters used to imagine the comet’s hair. Image credit: Gemini/Noirlab International Observatory/NSF/AURA/K. Meech (Ifa/U. Hawaii) Image processing: Jen Miller and Mahdi Zamani (NSF Noirlab
A race against the watch for scientists
Time is running out for researchers. 3i/Atlas will reach her point closest to the sun at the end of October, when she will begin to develop her characteristic cometary tail under the effect of solar heat. This crucial phase could reveal capital information on its internal composition and its origins.
The comet will temporarily disappear behind the sun in October and November, before reappearing and getting closer to earth in mid-December. It will then remain at a safe distance, about 1.6 times the Earth-Sun distance, representing no threat to our planet.
An appointment with history in 2026
Although too distant to be visible to the naked eye, 3i/Atlas should cleare themselves enough to be observable with an amateur telescope or simple binoculars. The best time to admire it will probably be early 2026, offering astronomy enthusiasts a unique chance to directly observe a messenger from another world.
This exceptional visit reminds us that our solar system is not isolated in the universe, but is part of a complex cosmic network where objects travel between the stars, carrying with them the secrets of distant worlds.
