This image of the Pinwheel Galaxy, or M101, combines data in the infrared, visible, ultraviolet and X-rays from four of NASA's space telescopes. The view shows that both young and old stars are evenly distributed along M101's tightly wound spiral arms. Such composite images allow astronomers to see how features in one part of the light spectrum match up with those seen in other parts. It's like seeing with a regular camera, an ultraviolet camera, night-vision goggles and X-ray vision, all at once!

The Pinwheel galaxy is in the constellation of Ursa Major (also known as the Big Dipper). It is about 70 percent larger than our own Milky Way galaxy, with a diameter of about 170,000 light-years, and sits at a distance of 21 million light-years from Earth. This means that the light we're seeing in this image left the Pinwheel galaxy about 21 million years ago -- many millions of years before humans ever walked the Earth.