Hypernova

[emmy]

What is a Hypernova?

A hypernova is the most destructive force in this universe. The power is almost incomprehensible and they seem to produce so much energy they defy the laws of physics. When one sets off it is the brighter than everything else you can see in the sky.

One hypernova releases millions of times more light than the all of the billions of stars in our galaxy put together.

What causes hypernovae?

Hypernovae are, like supernovae, formed from dying stars. In supernovae, a star grows rapidly, into a huge star called a red giant, but runs out of fuel. This means it suddenly collapses into a dense core, but then explodes outwards releasing a tremendous amount of energy. This blasts of the outer parts, leaving a neutron star. This doe not happen with most stars; only very heavy stars have sufficient energy for this.

A supernova awesomely powerful, but nothing compared to a hypernova. Hypernova are only formed by incredibly heavy and fast burning stars. A normal star may live for 10 billion years, but one that will become a hypernova will collapse in just 1 million. To burn this quickly they need a huge amount of fuel. The stars find this in what are called 'stellar nurseries', huge clouds of gas that combine to form stars. If a star can get enough gas it will have enough fuel to go through its whole life cycle in a tiny fraction of other stars. To do this these stars need to be around 20x the mass of our sun.

Unlike in a supernova the outer layers of the star are not blown off in an explosion. Instead, the star has so much gravity, because of its mass, that it continues to contract very rapidly. This converts all the gravitational potential energy of the star into heat and light. All the energy in the largest type of star is quickly converted into a form of radiation called 'gamma rays', and then unleashed on the rest of the universe. The effect of these is therefore called a 'gamma ray burst' (GRB). What is left behind is an incredibly dense lump of matter, called a black hole.

What would happen if a hypernovae occurred near Earth?

Here, 'near' is a relative term. 300 light years (almost 10,000 billion kilometres) is close enough for it to appear 1,000,000 times brighter than the sun. The destruction would be total: it would be like 1 million 1-megaton hydrogen bombs going off all over the world at once. That is very approximately 100 times the entire world's nuclear arsenal.

The first thing that would happen would be that the enormous heat would convert the nitrogen in the upper atmosphere to nitrous oxides. This would destroy the ozone layer that protects us from ultra violet light. Then the rest of the atmosphere would become superheated. It would be like Hiroshima all over the world. This would also trigger other forms of destruction: the high temperatures would cause cyclones, tsunamis and hurricanes all over the Earth.

An electro-magnetic pulse would also hit. If enough energy is released without there being matter to absorb it, it is converted to electro-magnetic energy. The size of the pulse from a hypernova would instantly destroy every electronic circuit on one half of the Earth.

The effect on the earth would be identical to a microwave. Invisible and silent rays would roast the atmosphere. If you were deep underground you could survive all this. But then what? All the plants and livestock would have burnt to death and going outside would be impossible because with no ozone layer, our own sun would continually bombard us with harmful rays. Most importantly of all, all the algae would die. Algae are tiny organism that produce most of the Earth's oxygen and are at the bottom of the food chain. With these dead, what life remained on Earth would slowly starve or choke to death. Earth would become a scorched, dead, uninhabitable planet.

There is absolutely no defence to any of this. We wouldn't even see it coming, as the gamma rays travel at the speed of light so the first time we detected them would be when they hit us.

How often to hypernovae occur?

Hypernovae occur frighteningly often. Every night more and more gamma ray bursts are located across the universe. They are so powerful we can see them 10 billion light years away, on the other side of the space. At this distance they are no threat, but if one were to occur even a few thousand light years away then the ozone layer would be destroyed and EMP would fry every electronic circuit on one half of the planet. Hypernovae are constantly occurring all over the universe, one day our luck will run out.

[Homer]

Hypernovaes are cool

If there's any star gazers out there, Eta Carinae could be ready to explode at any time, but I don't think it's known if it's a Supernova or Hypernova

[Althalus]

woohoo, never heard of these before, but damn if one was visible from earth would it not be able to be seen without telescopes?

that would be something to see.

[Kira]

Not sure but click here Might help has some great pics of it too

[Homer]

Thanks CW

That was the star I was referring to, but unfortunately, I don’t have time to find a pic of it. This could turn out to be a Hypernova

[j6p]

WHEW....this is some heavy stuff. I never heard of a hypernovna. Eta Carinae is magnificent.

[SpaceyKC]

I've got that pic as part of my screensaver~

it's so beautiful, but I didn't realize what it

really is!

[j6p]

Here's more info on hypernova and some prime candidates:

http://xxx.lanl.gov/abs/astro-ph/9712123

http://xxx.lanl.gov/abs/astro-ph/9903246

http://antwrp.gsfc.nasa.gov/apod/ap990420.html