EVANSTON, Ill. — Except for the fact that we call it home, for centuries astronomers didn’t have any particular reason to believe that our solar system was anything special in the universe. But, ...

For the inner four planets in this solar system, each planet orbits the sun three times for every two orbits of the planet immediately to its outside. For the fourth, fifth and sixth planets, they ...

Space scientists look back on 30 years of exoplanet discoveries — from rows of massive ‘super-Earths‘ to worlds with ...

Astronomers have found new evidence, revealing the existence of an unseen and mysterious planet that could be hidden in the ...

This illustration shows an exoplanet orbiting around two brown dwarfs –– objects bigger than gas-giant planets but too small to be proper stars. ESO/M. Kornmesser Astronomers have discovered a ...

The existence of "Planet Nine," a hypothetical planet in the outer solar system, is supported by indirect evidence such as the unusual clustering of orbits of extreme trans-Neptunian objects (ETNOs) ...

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 ...

Just as Earth orbits the sun, most planets discovered beyond our solar system orbit a host star. But some are out there all ...