Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

Astronomers propose a new hypothetical planet, Planet Y, beyond Neptune, based on observed orbital anomalies in the Kuiper ...

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

The solar system has many more moons than the one we can see in the sky. But how many do we actually know about? And how many ...

All solar system planets circle our sun with slightly tilted orbits — and a new study shows even distant planetary systems in quiet neighborhoods have orbital tilts, too.

The new image, which shows Earth along with an even smaller point of light coming from the moon, harkens back to Carl Sagan's ...

F or the first time, researchers have dated the formation of Jupiter by studying tiny, bead-like spheres found preserved in ...

Beyond the familiar planets lies a fascinating frontier filled with icy worlds, mysterious orbits, and cosmic curiosities.

All solar systems, including our own, are thought to have started out like this one, according to the scientists. But it’s estimated only 1-in-100 systems have retained that synchrony, and ours ...

All solar systems, including our own, are thought to have started out like this one, according to the scientists. But it’s estimated that only 1 in 100 systems have retained that synchrony, and ...