Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2006 May 17
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The Host Galaxies of Long-Duration GRBs
Credit: NASA, ESA, Andrew Fruchter (STScI), and the GOSH Collaboration

Explanation: What causes the powerful explosions knows 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.

Tomorrow's picture: open space

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