A star is racing out of the Milky Way at a blistering 2.6 million miles an hour (4.2 million kilometers an hour), astronomers report Thursday inScience, making it the fastest moving star ever found. Most other hypervelocity stars, as these speedsters are known, have been flung outward by the enormous gravity of the Milky Way's central black hole.
This one, by contrast, was probably launched on its high-speed trajectory by a kind of exploding star known as a Type Ia supernova, one of the most powerful and brightest bursts of energy in the universe. Nobody knows for sure what triggers a Type Ia, however—and the fast-moving star, known as US 708, might provide valuable clues.
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