Wednesday, May 21, 2008

Death of a Star: In the Right Place at the Right Time

The chance of witnessing two dying stars explode almost at the same time: 1 in 10,000. The chance of witnessing a double dose of supernovae with the correct type of telescope: really, really, really unlikely.

To top it off, there is no way to predict when and where deathly star explosions will happen, and only 1% of stars die in a supernova anyway. The rest fade away into white dwarfs, exhausted and completely out of nuclear fuel.

Nonetheless, Alicia Soderberg, a researcher at Princeton University, managed to beat unbeatable odds when she witnessed a supernova explosion from start to finish, while viewing the leftovers of a supernova in a nearby galaxy.

Soderberg happened to be gazing through NASA's Swift gamma-ray burst satellite,and picked up x-ray signals. The swift satellite is special because it can view X-rays. This is important if you want to spot a supernova: they can only be viewed in the X-ray wavelength.

Research published today in Nature show that Soderberg's spectacle is proof that bursts of X-rays occur when dying stars decide to take the explosive way out. The core of the star becomes heavier and heavier as its hydrogen converts into helium, which is subsequently converted into heavier elements, eventually turning into iron.

We often speak of things like stress weighing us down. But when your core has become giant aggregate of iron, I imagine that can get pretty intense. The iron core collapses, and explosion results from a shock wave of particles shooting out of the star shell.

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