Moving Right Along

StarDate: July 8, 2009

You are missing some Flash content that should appear here! Perhaps your browser cannot display it, or maybe it did not initialize correctly.


audio/mpeg icon

Hold on to your hats -- and everything else, for that matter. Like a crazy carnival attraction, Earth is spinning, circling, and racing -- all at the same time. And a recent study of the Milky Way galaxy says the ride is even faster than astronomers had thought.

The first motion is Earth's rotation on its axis -- one turn per 24 hours. Anything on the equator is rotating at more than a thousand miles an hour. Away from the equator, though, the rate is slower, because a slice through Earth is smaller.

The second motion is Earth's orbit around the Sun -- one per year. That works out to about 65,000 miles an hour.

And the third motion is the solar system's orbit around the center of the Milky Way galaxy. And that's where the new study comes in. It found that we're moving around the galactic center at around 600,000 miles an hour -- a good bit faster than earlier studies had shown. At that speed, we complete one turn around the galaxy every 200 million years.

Scientists made the discovery by using radio telescopes to map the locations and speeds of key landmarks throughout the galaxy. The observations show that many of these landmarks are moving faster than thought.

The reason is that the Milky Way is heavier than thought -- by about 50 percent. The gravity of all that extra mass pulls things along at a faster rate -- including our own solar system. That gives us an even wilder ride through the universe.

Script by Damond Benningfield, Copyright 2009

For more skywatching tips, astronomy news, and much more, read StarDate magazine.

The one constant in the Universe: StarDate magazine

FacebookTwitterYouTube

©2014 The University of Texas McDonald Observatory