The ancient Greeks proved over 2,000 years ago that the Earth was round and figured out how big it was by using simple observations of the Sun. But how do people know this today? When you drop ...

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. But how well do ...

The International Astronomical Union (IAU) defined a dwarf planet in 2006 as a celestial body that orbits the Sun, is round in shape, but has not cleared its orbital neighborhood of objects of ...

Dr Rudi Kuhn does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their ...

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Buzz Aldrin set foot on the moon, and his new book encourages kids to take the first steps onto ...

Ah, Earth. We may not think about our planet on a day-to-day basis, but the world we live in is a pretty interesting place. The third rock from the Sun—and to this day, the only one with known ...

The Planet Parade of 2025 is a truly extraordinary celestial event that has stargazers excited. From January 21 to mid-February, six planets will align in the sky: Venus, Mars, Jupiter, Saturn, Uranus ...

Did you know that our planet is rocketing around the sun at 67,000 mph? Or that it may once have been purple? Here are 50 facts about Earth. Gravity pushes extra masses of water and earth into a bulge ...