Earth Day is Saturday. To help celebrate, here are five interesting facts about our planet.
<strong>Third Rock</strong>
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 — the big one — life. Earth is one of the four terrestrial planet: Like Mercury, Venus and Mars, it is rocky at the surface.
<strong>Squashed sphere</strong>
Earth is not a perfect sphere. 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 not exactly opposed to gravity. This imbalance adds up at the equator, where gravity pushes extra masses of water and earth into a bulge, or "spare tire" around our planet.
<strong>She's got a waistline</strong>
Mother Earth has a generous waistline: At the equator, the circumference of the globe is 24,901 miles (40,075 kilometers). Bonus fact: At the equator, you would weigh less than if standing at one of the poles.
<strong>Treks around the Sun</strong>
The Earth isn't just spinning: It's also moving around the sun at 67,000 miles (107,826 km) per hour.
<strong>Extreme continent</strong>
The southern continent is a place of extremes, with the Antarctic ice cap containing some 70 percent of Earth's fresh water and about 90 percent of its ice, even though it is only the fifth largest continent. Did you know Antarctica is actually considered a desert? Inner regions get just 2 inches (50 millimeters) of precipitation a year (typically as snow, of course).
<em>Source: livescience.com</em>