The Host Galaxies of Long-Duration GRBs.

What causes the powerful explosions known as gamma-ray bursts? Astrophysicists still aren't sure, but the longest duration gamma-ray bursts (GRBs) seem to involve very massive stars. A new clue indicating this was uncovered recently by a series of images taken by the orbiting Hubble Space Telescope . These images, shown above , indicate that long duration GRBs typically appear to come from galaxies and regions of galaxies with bright regions rich with star formation and bright, massive stars . Long GRBs are therefore different than many types of supernovas , which occur more uniformly distributed in their host galaxies. Since such active star forming regions are relatively rare in our Milky Way Galaxy , the chances of a nearby GRB affecting life on Earth are relatively slight .