For centuries our solar system was the only planetary system known to humans. We had no proof other worlds existed beyond those in our own cosmic backyard, and we imagined that if other planetary ...

When you think of a planet, you probably think of one of the planets in our own solar system, like Earth, Jupiter, or Mars. Most of the exoplanets we’ve discovered have been like those in our solar ...

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 ...

We’ve found lots of “habitable” worlds but we don’t know what factors are needed for life. There are lots of reasons to search for planets around other stars—exoplanets. A big one is to find other ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. Planetary scientists are split, oscillating between two main theories that explain the order in ...

Scientists on Earth use seismometers to get a more detailed picture of what the inside of the Earth is made of. Those seismometers record vibrations from earthquakes. The vibrations change depending ...