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These four panels show the Whirlpool galaxy — which is actually a pair of galaxies also known as Messier 51 and NGC 5194/5195 — and how different wavelengths of light can reveal different features of a cosmic object. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici. The left image (a) shows the galaxy in visible light, from the Kitt Peak National Observatory 2.1-meter (6.8-foot) telescope and shows light at 0.4 microns (blue) and 0.7 microns (green). The next image (b) combines two visible-light wavelengths (in blue and green) and infrared ligh…
