Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short ...

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

The controversy endures over Pluto's true status, but the solar system underdog continues to capture hearts across the globe.

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 ...

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – here’s how to spot the celestial show ...

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