Cosmic Neighborhood, That Is
What’s the most powerful event you can think of in the universe? An asteroid crash onto the surface of a planet? A supernova explosion? Two black holes colliding? The Big Bang? Each of those events is powerful, and changes the objects involved. Take a gamma-ray burst, for example. It’s the catastrophic “monstrous” explosion of a hugely massive star as it dies. The stars that obliterate themselves in these monster events are dozens or perhaps even hundreds of times the mass of the Sun. They explode quickly, sending out huge amounts of radiation, including gamma-rays (the most deadly radiation we know of).
Most explosions of this type are extremely far away, but are so bright they can be seen across the universe. The initial flash tells astronomers that something happened, and they start to track its afterglow immediately. They’ve had some help in tracking these fantastic explosions from the SWIFT satellite, which has been studying the gamma-ray universe since 2004. It finds about 100 gamma-ray bursts a year.
Last April, the spacecraft spotted a GRB that was extremely bright and, in a departure from GRBs that are usually very far away, this one was actually in a relatively nearby galaxy. It exploded almost 4 billion years ago. The progenitor star (the star that blew up) was about 2o-30 times the mass of the Sun, and rotating extremely fast. That means it was a very compact star, of a type known to astronomers as a Wolf-Rayet star.
The work to identify and characterize this explosion was done at the Niels Bohr Institute in Copenhagen, Denmark. They’ve created a cool video about exploding stars that you can watch here.