Gamma Ray Bursts are very short lived, but incredibly powerful explosions, so bright that we can see them as far back as the earliest five percent of the universe's life time. It is thought that a star must collapse, or two stars must collide to produce one, so their presence is seen as good evidence of star formation. This is important because it gives us an idea of when stars began forming, and what the universe must have been like, billions of years ago.
But because they are so brief - lasting from a few seconds to maybe a few minutes - very little in known about them. The launch of the Swift satellite is changing all that because it sets in motion a cascade of observations in space and on the ground the moment it detects a blast.
This latest explosion has revealed a huge amount of detail about the polarisation of the "optical afterglow", the burst of light emitted in the blast that is thought to be caused by ejected material impacting the gas surrounding the dying star.
Until now, the composition of the ejected material has remained a mystery and, in particular the importance of magnetic fields has been hotly debated by GRB scientists. Either way, the early optical glow contains important clues for both these areas of research.
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