Does the sun rotate around the center of the galaxy?
Our sun and solar system orbit the center of the Milky Way galaxy at about 800 thousand kilometers an hour – that’s about 500 thousand miles an hour. So in the 90 seconds, for example, we all move some 20,000 kilometers – or 12,500 miles – in orbit around the center of the galaxy. But the galaxy is a big place. Even at this blazing speed, it takes the sun about 200 million years to complete one journey around the galaxy’s core. The orbital speed of a star around the center of our galaxy depends on its distance from the center. A star’s orbital speed can be predicted from the galaxy’s mass and the star’s location, but something mysterious is taking place at distances in the galaxy beyond the orbit of our sun. The speed of these outermost objects doesn’t decrease as much as expected. Astronomers think the reason may be a large amount of undetected mass around our galaxy – part of the unseen, dark matter of the universe.
