50 interesting facts about Earth
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. 1. We're the third rock from the sun (Image credit: Getty Images) Our home, Earth , is the third planet from the sun and the only world known to support an atmosphere with free oxygen , oceans of liquid water on the surface and life. Earth is one of the four terrestrial planets, according to NASA : Like Mercury, Venus and Mars, it is rocky at the surface. 2. Earth is squashed (Image credit: Markus Reugels, LiquidArt) Earth is not a perfect sphere. According to the National Oceanic and Atmospheric Administration (NOAA) , as Earth spins, gravity points toward the center of our planet (assuming for explanation's sake that Earth is a perfect sphere), and a centrifugal force pushes outward. But since this gravity-opposing force acts perpendicular to the axis of Earth, and Earth's axis is tilted, centrifugal force at the equator is ...