The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

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.

NASA's James Webb Space Telescope has been used to shed new light on the exoplanet, GJ 1214 b, which is more than eight times ...

New research shows that star activity can distort exoplanet measurements, affecting size, temperature, and atmosphere ...

This runaway growth led to the formation of the gas and ice giants in the outer solar system. This first-order model of planetary growth in the solar nebula is mainly driven by temperature and ...

These embryos, somewhere between small planetesimals and fully formed planets, were abundant during the solar system's formative ... but the size of the [parent body] is disputed." ...

For the first time, astronomers have imaged dozens of belts around nearby stars where comets and tiny pebbles within them are ...

A U.S. scientist searching for a civilization across 7 Earth clones circling the red dwarf star TRAPPIST-1 says its own alien astronomers could also be scanning Earth.