Astronomers say they have discovered a star cluster that has been thrown in the direction of Earth at a speed of more than two million miles per hour. The cluster, named HVGC-1, originated in the M87 galaxy and is expected to endlessly drift through space, rocketing through the voids between other galaxies. "Astronomers have found runaway stars before, but this is the first time we've found a runaway star cluster," said Nelson Caldwell of the Harvard-Smithsonian Center for Astrophysics, who is the lead author on a study which is set to be published in the The Astrophysical Journal. HVGC stands...