A big boom shortly after the Big Bang

Back in September of 2005, the Swift space telescope picked up a gamma-ray burst, a sign that an extremely violent event had occurred somewhere in the universe. No surprise really—this is what the Swift was designed to do. Most such bursts tend to last about 10 seconds, after which the glow quickly drops into less energetic wavelengths. This one was quite different. The burst itself lasted nearly 500 seconds and, as it was tailing off, briefly flared back to higher energies several times. Other telescopes joined in on the observations as the energy of the explosion dissipated and the wavelengths dropped. 老域名购买

Researchers are now done with the first analyses of the data, and it’s interesting stuff. Nature devotes three articles and a perspective to it, describing the burst itself, and its optical and infrared afterglows. The explosion was the second-most distant high energy object ever imaged, and it appears to have been produced by the formation of a black hole. But nicely behaved black hole formation these days results in a single, short burst. It’s unclear how the content of the early galaxies altered black hole formation, but something was clearly different from current conditions. Analysis of the afterglow also revealed that many heavy elements were already present at this early stage of the universe’s evolution.

My favorite aspect of the story, though, is how the incredible expansion of space-time since the explosion occurred affected the observations. Because the very fabric of space has expanded during the time the light travelled, the light itself stretched out with it. Although it took two minutes for Swift to move from sensing the burst to directing its focus on it, it didn’t miss as much of the burst as that implies. In terms of time at the actual point of the explosion, it only missed 23 seconds worth of data.

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