... Blue Stragglers In NGC 6397 . ... Villanova University ), NASA Explanation: In our neck of the Galaxy stars are too far apart to be in danger of colliding, but in the dense cores of globular star clusters star collisions may be relatively common. In fact, researchers have evidence that the row of six closely spaced blue stars just below the label in this Hubble Space Telescope image were formed when stars directly collided. ... The Star Clusters of NGC 1313 . ... Phi Persei: Double Star . ...