The face-on spiral galaxy M101, or the Pinwheel Galaxy, is seen at ultraviolet and optical wavelengths in this image taken by ESA’s XMM-Newton space telescope. The picture is composed of images taken by XMM-Newton’s Optical Monitor telescope using different filters: red (200–400 nm), green (200–300 nm) and blue (175–275 nm). Credit: ESA/XMM & R. Willatt Enlarge
(Phys.org) —The face-on Pinwheel spiral galaxy is seen at ultraviolet wavelengths in this image taken by ESA's XMM-Newton space telescope.
Also known as M101, the galaxy lies 21 million light-years away in the constellation Ursa Major. It measures 170 000 light-years across – nearly twice the diameter of our own Milky Way Galaxy – and contains at least a trillion stars. About a billion of these stars could be similar to our own Sun.
More often seen in visible light, here the Pinwheel Galaxy glows at ultraviolet wavelengths. Massive, hot young stars streaming with ultraviolet radiation mark out the galaxy's spiral arms with bright pockets of forming stars.
Since the largest stars are the shortest lived, with a maximum lifespan of a few million years, studying the ultraviolet radiation being emitted by a distant galaxy is a good way to measure how much star formation is taking place within it – and it is clear that M101 is still very active.
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