Huge gamma-ray blast spotted 12.2 bln light-years from earth

[username n/a]

WASHINGTON (AFP) – The US space agency's Fermi telescope has detected a massive explosion in space which scientists say is the biggest gamma-ray burst ever detected, a report published Thursday in Science Express said.

The spectacular blast, which occurred in September in the Carina constellation, produced energies ranging from 3,000 to more than five billion times that of visible light, astrophysicists said.

"Visible light has an energy range of between two and three electron volts and these were in the millions to billions of electron volts," astrophysicist Frank Reddy of US space agency NASA told AFP.

"If you think about it in terms of energy, X-rays are more energetic because they penetrate matter. These things don't stop for anything -- they just bore through and that's why we can see them from enormous distances," Reddy said.

A team led by Jochen Greiner of Germany's Max Planck Institute for Extraterrestrial Physics determined that the huge gamma-ray burst occurred 12.2 billion light years away.

The sun is eight light minutes from Earth, and Pluto is 12 light hours away.

Taking into account the huge distance from earth of the burst, scientists worked out that the blast was stronger than 9,000 supernovae -- powerful explosions that occur at the end of a star's lifetime -- and that the gas jets emitting the initial gamma rays moved at nearly the speed of light.

"This burst's tremendous power and speed make it the most extreme recorded to date," a statement issued by the US Department of Energy said.

Gamma-ray bursts are the universe's most luminous explosions, which astronomers believe occur when massive stars run out of nuclear fuel and collapse.

Long bursts, which last more than two seconds, occur in massive stars that are undergoing collapse, while short bursts lasting less than two seconds occur in smaller stars.

In short gamma-ray bursts, stars simply explode and form supernovae, but in long bursts, the enormous bulk of the star leads its core to collapse and form a blackhole, into which the rest of the star falls.

As the star's core collapses into the black hole, jets of material blast outward, boring through the collapsing star and continuing into space where they interact with gas previously shed by the star, generating bright afterglows that fade with time.

"It's thought that something involved in spinning up and collapsing into that blackhole in the center is what drives these jets. No one really has figured that out. The jets rip through the star and the supernova follows after the jets," Reddy said.

Studying gamma-ray bursts allows scientists to "sample an individual star at a distance where we can't even see galaxies clearly," Reddy said.

Observing the massive explosions could also lift the veil on more of space's enigmas, including those raised by the burst spotted by Fermi, such as a "curious time delay" between its highest and lowest energy emissions.

Such a time lag has been seen in only one earlier burst, and "may mean that the highest-energy emissions are coming from different parts of the jet or created through a different mechanism," said Stanford University physicist Peter Michelson, the chief investigator on Fermi's large area telescope.

"Burst emissions at these energies are still poorly understood, and Fermi is giving us the tools to understand them. In a few years, we'll have a fairly good sample of bursts and may have some answers," Michelson said.

The Fermi telescope and NASA's Swift satellite detect "in the order of 1,000 gamma-ray bursts a year, or a burst every 100,000 years in a given galaxy," said Reddy.

Astrophysicists estimate there are hundreds of billions of galaxies.

The Fermi gamma-ray space telescope was developed by NASA in collaboration with the US Department of Energy and partners including academic institutions in France, Germany, Italy, Japan, Sweden and the United States.

Link:
http://news.yahoo.com/s/afp/20090219...spaceastronomy

[i_got_a_mohawk]

We're dooooooomed

[Bruce Lindfield]

I can remember going on a Science Summer School at Sussex University several years ago and doing Cosmology - this kind of thing was a big discussion topic!

So the scientists said that we observe things like this all the time and that nobody really knows what it is - there was speculation that it could be advanced civilisations discovering the secret of limitless energy and blowing themselves up in the process!!

Thus explaining the mystery of why although there must be intelligent life out there, given the size of the Universe - we haven't seen them - so they inevitably destroy themselves, before getting round to visiting us!!

[katri]

Could this be a danger? It happened 12.2 billion years ago.
I doubt it

[bassist 4 life]

Light years are not a measure of time.

[hover]

Originally Posted by katri

Could this be a danger? It happened 12.2 billion years ago.
I doubt it

[Bruce Lindfield]

Originally Posted by katri

Could this be a danger? It happened 12.2 billion years ago.
I doubt it

But these events are happening all the time - astronomers pick up evidence everywhere they point telescopes!

[katri]

Originally Posted by bassist 4 life

Light years are not a measure of time.

True, but, a light year is how far light can travel in 1 year so if something happens 12.2 billion light years away we wont see it for 12.2 billion years as the light takes that long to reach us,
e.g if the Sun blew up now we wouldnt know for 8 minutes as that is how long the light from the sun takes to reach earth, if the sun were 12.2 billion light years away then it would take 12.2 bill years for us to realise.

[WRBass]

Originally Posted by bassist 4 life

Light years are not a measure of time.

Light years are a measure of distance. But, this did happen 12.2 billion years ago. BTW, it was long before our solar system and sun were even formed!

[bassist 4 life]

strop trying to turn my pwn win into a fail!!!

[Bruce Lindfield]

Originally Posted by WRBass

Light years are a measure of distance. But, this did happen 12.2 billion years ago. BTW, it was long before our solar system and sun were even formed!

But there are almost certainly similar events happening now, somewhere in the Universe - it's just that they are so far away, that the light from them will take billions of years to reach us - hopefully!!

When we discover the secret of the limitless energy inherent in the Universe, then it might be a bit closer!!

[hover]

Originally Posted by Bruce Lindfield

When we discover the secret of the limitless energy inherent in the Universe, then it might be a bit closer!!

No if Doc Oc has anything to say about it! We'll just drop it in the river!

KA-BOOOM!

[RWP]

I wonder what the odds are that a burst would hit the earth destroying our planet?
Add that to killer asteroids and that super volcano out west as more things to worry about.

[Disraeli Gears]

Originally Posted by bassist 4 life

Light years are not a measure of time.

Yes, but by the time the light gets here and we are able to see it, the event already happened. For example, the sun is 8 light minutes away. That means that it takes 8 minutes for the light from the sun to reach us here, and so if we see the sun, we actually see where the sun was 8 minutes ago because it took the light that long to get to us.

Now if we see something that's 12 billion light years away, the same applies. The distance means that's how long it takes the light to travel, so we see it as it was 12 billion years ago.

[Bruce Lindfield]

Originally Posted by RWP

I wonder what the odds are that a burst would hit the earth destroying our planet?

Well - given that the Universe is Infinite - then it's very close to Infinity : 1

[Jerose]

I felt a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were suddenly silenced. I fear something terrible has happened.

[PSPookie]

Originally Posted by Jerose

I felt a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were suddenly silenced. I fear something terrible has happened.

Dude, you must be way old. Or do transmisions of force-related information travel no faster than the speed of light?

[RWP]

Originally Posted by Bruce Lindfield

Well - given that the Universe is Infinite - then it's very close to Infinity : 1

Good, I feel better now.

[Bruce Lindfield]

Originally Posted by PSPookie

Dude, you must be way old. Or do transmisions of force-related information travel no faster than the speed of light?

In science-fiction and some science there is a concept of instantaneous communication via "the ansible".....

Google it!

[bassybill]

Originally Posted by katri

Could this be a danger? It happened 12.2 billion years ago.
I doubt it

So the fact that some gamma rays reaching you set out 12 billion years ago would stop them being dangerous how, exactly?