Low and medium energy X-rays in red and green show expanding debris from the supernova explosion. High energy X-rays in blue reveal the blast wave, a shell of extremely energetic electrons. Also shown in the lower left region of Tycho is a blue arc of X-ray emission. Several lines of evidence support the conclusion that this arc is due to a shock wave created when a white dwarf exploded and blew material off the surface of a nearby companion star. Previously, studies with optical telescopes have revealed a star within the remnant that is moving much more quickly than its neighbors, hinting that it could be the companion to the supernova that was given a kick by the explosion.