Sunday, January 13, 2008

How fast is the Earth moving through space?

The Earth is speeding like a top and like a merry-go-round horse on a carousel that is itself riding on a larger carousel, and the whole amusement park is moving through space.

The Earth rotates on its axis at about 460 meters per second at the equator. The speed of a trip around the Sun is about 30 km per second. Meanwhile, the solar system is in a more-or-less circular orbit around the center of the galaxy at an average velocity of about 220 kilometers a second, according to Facts on File Dictionary of Astronomy, and the galaxy is moving at about 19.4 kilometers a second, toward a point in the constellation Hercules called the solar apex. Some authorities believe that there is also a general drift by the Milky Way and some neighboring upper clusters towards the Southern Cross at a speed of more than a million miles an hour.