Spiral galaxies are among the most beautiful objects in the sky, and one of the most beautiful of them is M101, also known as the Pinwheel Galaxy. It's a reliable favorite among amateur astronomers because it's big, bright, and located near the north pole of the sky, so it's easy to find for a big part of the year. I've seen it many times through a telescope, but not quite like the way NASA's Wide-field Infrared Survey Explorer (WISE) saw it: glowing fiercely in colors our eyes cannot detect:
[Click to galactinate.] This image shows the galaxy in the far-infrared. What you see here as blue is actually starlight; green is from long organic compounds called PAHs, and red is from glowing dust, warmed by nearby star formation. Look at the gigantic red clouds where stars are being born! Thousands of these have been catalogued in the Pinwheel.
It's actually ...
