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

Watch this video to find out more about the Earth, planets in our Solar System and other planets far ... Some are the size of small stones and pebbles. Some measure hundreds of kilometres across.

ISTOCK / GETTY IMAGES PLUS The planets in our solar system orbit the sun in roughly the same plane, known as the ecliptic, which is tilted relative to Earth's equator by about 23.5 degrees.

"Relatively small planets similar to the size of Earth are ... There are nearly 300 moons in our solar system, but their masses are typically much smaller relative to their host planets than ...

Keep your eyes on the sky. Six planets in our solar system are coming into alignment and will be visible from Earth. AccuWeather says Saturn, Venus, Neptune, Uranus, Jupiter and Mars will be ...

A planet-size object that possibly once visited the solar system may have permanently changed our cosmic neighborhood by warping the orbits of the four outer planets, a new study suggests.

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known ...