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The red arc in this infrared image from NASA's Spitzer Space Telescope is a giant shock wave, created by a speeding star known as Kappa Cassiopeiae. It is a massive, hot supergiant moving at around 2.5 million mph relative to its neighbors (1,100 kilometers per second). But what really makes the star stand out is the surrounding, streaky red glow of material called a bow shock, in its path. (Image Credit: NASA/JPL-Caltech)