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

Try stargazing. Need a new idea to keep kids entertained? Try stargazing. Free learning activities and videos about the solar system Free learning activities and videos about the solar system Free ...

If we ever manage to travel to the gas planets ... are parts of the distant Solar System that we know about, such as the Kuiper Belt. It's all good and well knowing facts about space, but how ...

With a radius of 2,106 miles, Mars is the seventh largest planet in our solar system and about half the diameter of Earth. Its surface gravity is 37.5 percent of Earth’s. Mars rotates on its ...

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

It is a world of extremes. Explore facts about our solar system's fastest planet. Mercury is slightly larger than our Moon - 15,329 kilometres around its equator. Its radius, the distance from the ...

Here are 12 facts ... be back. Solar storms start with a sunspot. The sun is a giant ball of always-active gases.

There may be an undiscovered planet in the outer solar system whose presence is revealed by the strange orbit of objects beyond the eighth planet Neptune. The tantalizing prospect of a ninth ...

While the planets won’t be perfectly aligned, their placement will follow the orbital plane of our solar system. Which planets are parading in January and February? The January planetary ...