There could be a ninth planet in our solar system that's lying in wait to be discovered - and no, it's not Pluto. Our solar ...

CAPE CANAVERAL, Fla. (AP) — Astronomers have discovered the earliest seeds of rocky planets forming in the gas around a baby sun-like star, providing a precious peek into the dawn of our own solar ...

Mercury has long baffled astronomers because it defies much of what we know about planet formation. A new space mission ...

An artist's illustration of a possible ninth planet in our solar system, hovering at the edge of our solar system. Neptune's orbit is shown as a bright ring around the Sun. Scientists in Taiwan ...

Astronomers have finally pinned down the mass and distance of a lonely world that drifts through the galaxy without a parent ...

This artist’s concept depicts one of the solar system’s inner planets slamming into Earth after being nudged on a collision course by a passing star. Such a world-shattering cataclysm is extremely ...

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 ...

A tiny meteorite is rewriting what scientists thought they knew about the origins of our solar system. New evidence found in shavings from a meteorite known as Northwest Africa 12264 — a 50-gram (1.8 ...