The word planet comes from the Greek πλανήται (planḗtai) 'wanderers'. In antiquity, this word referred to the Sun, Moon, and five points of light visible to the naked eye that moved across the background of …

May 28, 2025 · A more modern definition can be found in the Merriam-Webster dictionary which defines a planet as "any of the large bodies that revolve around the Sun in the solar system."

Nov 20, 2025 · Planet, broadly, any relatively large natural body that revolves in an orbit around the Sun or around some other star and that is not radiating energy from internal nuclear fusion reactions. …

May 21, 2024 · Discovered in 1930, it was long considered the ninth planet in our solar system. But in 2006, the International Astronomical Union revised its definition of a planet. Under the new definition, …

Dec 19, 2025 · An unusual object orbiting a rapidly spinning star might be a new phenomenon in the universe.

The English word planet comes from the Greek planēs. Unlike the ancient Greeks, we now know that the planets "wander" across the sky because they are revolving around the sun.

Learn why these worlds are so important, and how you can get involved. We study the Sun to learn about how stars work, and to help protect our civilization from solar storms. Mercury a little-explored …

Interactive night sky map for any location. Which planets, stars, constellations, and comets are visible tonight?

When the heliocentric model gained sway in the sixteenth century, it became accepted that a planet was actually something that orbited the sun, and Earth was itself a planet, and the sun and moon were not.

Mar 12, 2025 · What is a Planet? The word goes back to the ancient Greek word planēt, and it means "wanderer." A more modern definition can be found in the Merriam-Webster dictionary which defines …