What is known about the new comet 3I/ATLAS — is it dangerous for the Earth

Back in the summer, astronomers recorded a new space object — comet 3I/ATLAS. She became the third intergalactic visitor in history to visit our Solar system. In early October, the comet reached its closest approach to Mars and became closer to Earth. What is remarkable about this astronomical event and whether it poses a danger to earthlings, Izvestia tells.

What is Comet 3I/ATLAS known for?

Comet 3I/ATLAS is an interstellar object outside the Solar System. It was first spotted on July 1, 2025 by the ATLAS asteroid collision warning system in Rio Hurtado, Chile. It was named after her. The first letter "I" indicates the category of the comet, in this case "interstellar", and the number "3" indicates that this is the third object of its kind in the history of observations.

Due to the unusual trajectory, reports have appeared in the press that the visitor from outer space may be an alien ship. These concerns were reinforced by the words of Harvard astrophysicist Avi Loeb, who stated that the object emits its own radiance, similar to the light from the headlights of a car. This means that it has a powerful energy source capable of generating light, which is not typical of ordinary cosmic bodies.

However, in the new report, Loeb clarified that the glow is most likely caused by dust that rises from the surface of the object when it is heated by the Sun. He also said that 3I/ATLAS could reach Earth by the end of 2025.

Later, on October 3, it was reported that 3I/ATLAS reached its maximum approach to Mars at a distance of 29 million km from the planet. According to the European Space Agency (ESA), the comet, which may be billions of years old, is moving at a speed of about 210,000 km/h. The distance to the Earth is 240 million km, which is one and a half times the distance to the Sun.

According to astronomers, the celestial body poses no danger either to our planet or to other planets of the Solar System, since its trajectory does not intersect with our orbit. The comet will come closest to the sun at the end of October, and then fly back into interstellar space.

What is an interstellar object?

The term "interstellar object" appeared quite a long time ago in the context of futurology and cosmonautics. However, it acquired its official status relatively recently due to new discoveries. Today, this is the name given to comets, asteroids and other cosmic bodies that are not gravitationally bound to any of the stars and wander in interstellar space, briefly entering the Solar System.

Such objects are characterized by high velocity and highly elongated hyperbolic orbits. Their appearance is of great scientific interest, as they are in their own way "time capsules" that can provide valuable information about other star systems, their composition and the formation processes of other worlds.

After passing through our Solar System, cosmic bodies leave it forever, returning to interstellar space. Astronomers do not rule out that with the development of telescopes, the detection of such objects will become more common.

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Where is the asteroid Oumuamua now?

The first known interstellar object was the asteroid Oumuamua, which was discovered by the Pan-STARRS1 telescope of the University of Hawaii, funded by the NASA program, on October 19, 2017. It was first noticed in the area of the star Vega from the constellation Lyra. This unusual reddish-colored object wandered through the Milky Way for hundreds of millions of years before its encounter with the Solar System.

Astronomers dubbed it as the "messenger from afar," which is how the name translates from Hawaiian. Due to the unusual elongated shape and atypical acceleration, scientists could not determine for a long time whether it was a comet, an asteroid, or an object of artificial origin. It was originally classified as comet C/2017 U1, but later designated as asteroid A/2017 U1.

Later, the International Astronomical Union (IAU) introduced a special index "I" for space bodies of this type (abbreviated from English interstellar — "interstellar"), and the designation was changed to 1I/2017 U1.

In January 2019, Oumuamua went beyond the orbit of Saturn, leaving our Solar System, and headed for the constellation of Pegasus. Currently, he has gone too far and is inaccessible for observation.

Another interstellar body, Comet Borisov (2I/Borisov), was discovered on August 30, 2019 by Russian amateur astronomer Gennady Borisov. Unlike its stellar predecessor, the comet was discovered early enough, so it was possible to observe it much more. However, nothing remarkable has been determined, except for its extrasolar origin.

Earlier, Izvestia reported that Comet 3I/ATLAS had changed its color.

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