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

Somewhere at the edge of the solar system a new Earth-sized world might be lurking, dubbed Planet Y. Astronomers have long proposed that there might be hidden planets beyond the Kuiper belt, a region ...

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

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

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 dubbed ...

Could the icy moons of our solar system hold life beyond our planet? Keith Cooper looks at how planetary scientists plan to ...

When the Sun runs out of hydrogen fuel and expands into a red giant, it will eventually encompass the innermost planets of the solar system, out to about Earth’s orbit. Being closer to our enlarged ...

Stars passing close to the sun could cause planets to collide, including with Earth, or even be ejected as rogue planets, new simulations show. By Katherine Kornei If our species manages to hang on ...

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 ...

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 ...