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Mars and Regulus III

June 8, 2010

In movies and TV shows, the galaxy is like a well-laid-out city: All the star systems are perfectly aligned with each other, so a visiting starship never has to tilt or turn to enter orbit around the next star over.

But the real galaxy is a lot less orderly. Stars are tilted at all angles, and they aim in all different directions.

An example is Regulus, the brightest star of Leo, the lion. It's in the west this evening, and forms a striking pair with bright orange Mars.

As seen from Earth, Regulus is turned on its side. And as it orbits the center of the galaxy, its poles line up with its direction of travel. So if you approached Regulus in a starship, you'd have to tilt about 90 degrees to line up with the orbits of any planets that might circle the star.

The view of Regulus would be quite different from the Sun, too. The star spins so fast that it's fatter through the equator than the poles. In profile, it looks like a football. And since the gas at the equator is much farther from the star's core, it's much cooler than the poles, so it looks darker.

One other difference in the view is that Regulus appears to have a white dwarf companion -- the "dead" core of a star that was once something like Regulus itself. It's no bigger than Earth, but it's intensely hot. As it neared the end of its life, this star may have dumped some of its gas onto Regulus -- causing the star to spin like an out-of-control Ferris wheel.

Script by Damond Benningfield, Copyright 2010

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