The celestial show of interstellar comet 3I/ATLAS is preparing to take a break. The space traveler, who came to us from the depths of the Milky Way, will soon temporarily disappear from the view of observers on Earth. The reason lies in orbital motion: our planet and the comet will soon be on opposite sides of the Sun. The bright light of the star will completely obscure the faint glow of the comet, making it impossible to observe.

Illustration of comet 3I/ATLAS approaching its perihelion. Author: Copilot AI

The comet is now only a few degrees from the Sun in the sky, setting about an hour after dusk. This creates a narrow window of opportunity for its detection. However, only those with powerful telescopes will be able to see it.

3I/ATLAS now looks like a faint spot located approximately at the distance of Mars’ orbit. Soon, the angular distance between it and the Sun will begin to decrease rapidly, and by the end of October, they will converge at their minimum distance.

Non-standard trajectory

Position of comet 3I/ATLAS as of the end of September 2025

Despite this proximity, Comet 3I/ATLAS will not approach the Sun in the same way as ordinary comets do. The point of its perihelion, its closest approach to the star, will be reached on October 29. At that moment, it will be a full 202 million km away from the Sun. This distance means that Earth will miss the most interesting phase of the comet’s activation, when solar heat would intensively evaporate ice from its core, forming a bright tail.

Unique space visitor

This comet differs sharply from the two previous interstellar visitors – 1I/Oumuamua and 2I/Borisov. It moves almost twice as fast and is much larger. Its origin is also different: most likely, the interstellar visitor arrived from the “thick disk” of our galaxy, rather than from the region where the Solar System is located.

The 3I/ATLAS study is key to understanding the nature of interstellar objects and the structure of other planetary systems. Even its recent change to green has sparked keen interest among scientists.

Back to the skies

Fortunately, this is not the last appearance of the mysterious guest. Scientists predict that the comet will once again be visible from late November, just before its closest approach to Earth. The minimum distance to our planet will be 268 million km. Although it is not a close encounter, astronomers are already preparing their instruments to obtain valuable new data about this unique interstellar traveler.