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

Every object in our Solar System is ... km from the planet, the rings have an average thickness of only 10m. The rings are thought to be bits of comets, asteroids, or moons that broke up before ...

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

The next Sputnik Moment will take place against the backdrop of great power competition, as it did in the 1950s. This time, the top contenders are the U.S. and China. There are many obstacles to ...

Mercury takes only 88 Earth days to orbit the sun.

Ultimately, the question of why some planets have moons is still widely debated, but factors such as a planet’s size, ...

In fact, every planet—and every moon—in the solar system will be in the sky during the eclipse. However, that doesn’t mean you’ll see them all. Contrary to what you might have read ...

Mars, Venus, Jupiter and Saturn should be visible to the naked eye, but get a telescope and you can spot Neptune and Uranus.

Extrasolar planets contextualise the Solar System among a large number of planetary systems with very different properties. Many extrasolar planets show characteristics which are not realised in the ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...