Mercury is putting on a show for skywatchers in the evening sky after sunset. But how well do you know the planet Mercury? Here's some Mercury trivia to ponder while planet gazing.

Our solar system's planets vary greatly in size, composition, temperature, chemistry and geology. Here are some notable extreme facts about the planets that orbit our Sun.

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American astronomers say they have found strong evidence that a ninth planet might exist in our solar system. Here are nine things we know about 'Planet Nine'.

We have just entered a very favorable period for observing the so-called "elusive" planet Mercury. From now, until about May 13, you should be able to find it with not much difficulty. In 1965 ...

Read these 75 interesting and cool facts about Earth to learn more about our planet.

American astronomers say they have found strong evidence that a ninth planet might exist in our solar system. Here are nine things we know about 'Planet Nine'.