The Pinwheel Galaxy, which can be found more than 21 million light-years from Earth in the constellation of Ursa Major, is one of the most majestic galaxies in the observable universe. The only thing more impressive than the galaxy's beauty is its size. It comes in with a staggering diameter of 170,000 light-years, making it about 70% larger than our home galaxy, the Milky Way (it, in contrast, is about 100,000 light-years across).
You may not know this, but capturing a detailed image of distant galaxies isn't as easy as clicking a button on a camera. For instance, take the beautiful photograph of the Pinwheel Galaxy seen here. Instead of it being one shot, it's actually a composite of four shots taken in infrared, visible light, ultraviolet and x-ray. Optical data was collected by the Hubble Space Telescope (in yellow). The Chandra X-ray Observatory captured the galaxy at x-ray wavelengths (seen in purple), while the Spitzer Space Telescope viewed it at infrared wavelengths (seen in red). Ultraviolet data was taken by GALEX - the Galaxy Evolution Explorer - in blue.