Scientists weighed newborn planets for the first time, revealing puffy worlds that will shrink into super-Earths and ...

The orbits of the planets around the sun have been the source for many a scientific debate. Their current orbital properties are well understood but the planetary orbits have evolved and changed since ...

The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course. When ...

On January 5, 2005, astronomers at NASA discovered Eris, the second-largest dwarf planet in the solar system. Eris is just ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...

Astronomers may have finally worked out how planets between the size of Earth and Neptune – which aren't found in our Solar ...

With sapphire waterfalls, lava rain and orbits around dead stars, these distant worlds push the limits of what’s possible.

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...