New discoveries of objects in the Kuiper Belt have also presented challenges for the Planet Nine theory. The latest is known ...

Harvard astronomer Avi Loeb suggests that if interstellar object 3I/ATLAS isn't a comet, nor an asteroid, it may have been ...

Using data from the Vera C Rubin Observatory, experts have revealed just how big the object, dubbed 3I/ATLAS, really is.

Astronomers have discovered a "fossil" world lying in the outskirts of the solar system, according to new research.

Astronomers have discovered a "fossil" body residing on the outskirts of the solar system, according to new research. The object – which goes by the formal designation 2023 KQ14 but is nicknamed ...

The celestial body's unusual orbit “implies that something extraordinary occurred" in the early days of the solar system—and ...

Astronomers have confirmed the third interstellar object on record is dashing through our solar system. Dubbed 3I/ATLAS, it ...

A mysterious visitor from another solar system could be an alien spacecraft, according to a leading Harvard astronomer.

A mysterious object the size of Manhattan is blazing through our solar system, and its origins remain a puzzle to the world's ...

In the dark, icy outskirts of our solar system—far beyond Neptune's orbit—astronomers have discovered a cosmic oddball that ...

Comet 3I/ATLAS was first identified by the Asteroid Terrestrial-impact Last Alert System (ATLAS), a global network of four ...