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

Ptolemy’s model and many earlier ideas of the Solar System had the Earth at the centre of it. As observations of the motions of the planets became more detailed, the descriptions of the Solar ...

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

This may explain the strange properties of the orbits of our solar system's planets, which are not quite perfectly circular, and all lie on slightly different planes. NASA artist’s conception of ...

NASA issues warning over construction project in China slowing down Earth's spin Discovery of unique asteroid-comet hybrid gives clues about Solar System origins Among the 85 exoplanets - planets ...

However, this year a powerful new telescope is coming online that could prove once and for all that there really is a ninth planet in our Solar System. The same year that Pluto was ignominiously ...

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 ...

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 ...

A planet-sized visitor possibly visited the solar system billions of years ago and permanently changed the cosmic neighbourhood by warping the orbital path of four outer planets of the system ...