My Dark Sky

If you ask any astronomer what is the most powerful explosions in the Universe, the answer will definitely be gamma ray burst.

How powerful is it?

Imagine the energy that our Sun put out in its entire 10 billion years lifetime, gamma ray burst only needs a few seconds to release them all!

Basically, gamma rays are just “light” (electromagnetic waves), same as the familiar visible light that we can see but with much shorter wavelengths and thus contains higher energy. In fact, it is the highest energy photons in the electromagnetic spectrum, billions of times more energetic than visible light.

Gamma ray bursts (GRB) are very intense and short bursts of gamma-ray radiation in the sky. They were actually first discovered by accident. In the 1960s during the Cold War, US launched the Vela satellites to make sure that the Soviet Union (specifically and other nations generally) adhered to the nuclear test ban treaty. The satellites will look for nuclear testing by detecting gamma rays that are given off during nuclear explosion.

And Vela did detected bursts of gamma ray. However, the distributions of these gamma rays don’t look the same as the ones you get from nuclear test; the bursts are not coming from our planet, but from space. They seemed to be coming from all over the universe at random and at unexpected times – they are totally unpredictable.

So, now we know the bursts came from space. But exactly where? From our Solar System? within our Milky Way Galaxy? or galaxies far far away?

…to be continued…

~ by thChieh on October 29, 2008.

Posted in General Astro Talk
Tags: gamma ray burst