COSI Blog
31
May
2013

Update: A Bang for the Flash!

Update: A Bang for the Flash!

They did it. A large collaboration of scientists, watching the spot in the constellation Leo where a humongous gamma ray burst occurred in late April, have seen the giant supernova explosion they were expecting after such a monumental event. Not only that, but the explosion was so large and powerful that it created the universe's oddest inhabitant – a black hole!

The supernova explosion was of a sort called Type Ic. This is fancy astronomer talk for an explosion with no hydrogen in it. This is odd, since most stars (including our Sun) are made almost entirely of hydrogen. In a star such as the one in question has used up nearly all its hydrogen in thermonuclear fire, and what it didn't use, it has now blown off into space.

Think of that! A star so hot, so powerful, that it blows bunches of its own mass off into space. What do I mean by bunches? How about three Earths-worth of hydrogen every year!

Stars are big, but they're not infinitely big. Eventually, the outer layers of such a star are all gone and all that remains is the white-hot core. When that core finally runs out of fuel, the star collapses. The immense implosion is followed by an even more impressive (to us here on Earth) explosion which can outshine an entire galaxy.

This is exactly what happened in Leo over the past month. First we saw the gamma rays, the most energetic light from the explosion. After that came x-rays, ultraviolet, and finally the visible light that let astronomers know with confidence that the gamma ray burst of April 27 really was the harbinger of an exploded star. Identifying it as a Type Ic supernova gives astronomers more confidence that their models of stellar death are on the right track.

Before we leave this story, though, let's go for a minute inside this exploded behemoth. When stars die, their remnants are often compressed to amazing density. A neutron star, for instance, (the remains of a smaller supernova than this one) is so dense that a teaspoonful would weigh a billion tons. A black hole is not just denser than a neutron star, however. A black hole is, as far as we know, infinitely dense! Black holes are so dense, in fact, that nothing, not even a light beam, can escape from them. Were you to venture too close to such a beast, you could never be heard from (or seen!) again, as you would fall toward the black hole and have any signal you might send – a laser pointer, a cell phone signal, even a gamma ray – swallowed up with you.

Amazingly, even though we can never venture inside one of these beasts, we can, through the power of science, understand how they work and where they come from. This week, thanks to the hard work and careful observations of a team of dedicated astronomers, we understand them a little better.

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