Cosmic Rays From Galactic Black Holes

dork writes in with word of a study that contradicts, at least for the highest-energy events, the recent conclusion that cosmic rays are probably formed in supernova remnants. The Pierre Auger Observatory in Argentina has announced that active galactic nuclei are the most likely candidates for the source of the highest-energy cosmic rays that hit Earth. The researchers found that the sources of these highly energetic events are not distributed uniformly across the sky, linking their origins to the locations of nearby galaxies hosting active nuclei in their centers. These galaxies are thought to be powered by supermassive black holes that are devouring large amounts of matter. The exact mechanism of how particles get accelerated to energies 100 million times higher than achievable by the most powerful particle accelerators on Earth is still unknown. The observatory has made 1% of its events available through a public online event display."

well it might be a good science source

[PermanentMarker]

hmm thinking about it even the new HDC cann't speedup atoms like those Blackholes do (about 99.9% speed of light) with thise speeds i read the atoms do weight as much as a bacterium.

In other words if they used this data they had the best accelerator

So why dont they use it to gather data ????

Re:

[John Hasler]

> So why dont they use it to gather data ?

They do.

Re:well it might be a good science source

[bockelboy]

Cosmic rays can provide some interesting information for physicists.

In fact, since the particle accelerator for the LHC has not yet turned on, the only real "data" to speak of is cosmic rays passing through the detectors. It's great background noise to make sure everything is working.

However, it's not as good as an accelerator for a couple of reasons:
1) Most interesting particles are the decay products of a collision, not necessarily in cosmic rays.
2) Repeatability. While protons in the LHC may collide at 100Hz or so, cosmic rays are a little less predictable.
3) Statistics. To show the existence of a new particle, you need statistics at 5-sigma. This might require tens or hundreds of thousands of recorded events of a certain signature in order to be considered reliable. You simply can't get that from cosmic rays.

(3) is why some results from the Tevatron are just now getting interesting - the device has simply been running long enough to make the discovery of the Higgs a remote possibility because of the sheer number of days running and events recorded. Because the energies of the LHC are going to be much higher and at a greater rate, the Higgs search should be much faster on that machine.

(I am not a particle physicist. I just work for them.)

A few corrections...

[Roger W Moore]

Most interesting particles are the decay products of a collision, not necessarily in cosmic rays.

The problem here is one of energy. Cosmic rays do actually "collide" with the ATLAS detector but the energy available is far, far lower than current colliders plus most of the cosmic rays are muons which mean that they only rarely have a real collision.

Repeatability. While protons in the LHC may collide at 100Hz or so, cosmic rays are a little less predictable.

You are a few orders of magnitude off here. The LHC proton bunches collide at 40MHz and there are roughly 20 collisions per crossing at nominal intensity. In fact the bunches collide so rapidly that the particles from the preceding collision have not actually escaped the detector by the time the next bunch crossing occurs. On the other had, at the surface, one cosmic ray will pass through 1cm3 every second. Down in the detector pit this is less but what also kills the rate is that we want a direction that will pass through most of the detector.

Statistics. To show the existence of a new particle, you need statistics at 5-sigma. This might require tens or hundreds of thousands of recorded events of a certain signature in order to be considered reliable. You simply can't get that from cosmic rays.

Actually new particles have been found in cosmic rays - that is how the muon (heavier brother of the electron) was discovered in 1935/6 (IIRC). To get to 5-sigma you simply need a lot more signal events than background events. If your backgrounds are very low then you don't need many events at all.

(I am not a particle physicist. I just work for them.)

I am a particle physicist and while I don't know whom you work for or in what capacity - thanks! A lot of people don't realise that while there are a lot of physicists working on theses experiments there are even more technicians, engineers, machine operators etc. behind the scenes making it all possible.

Staggering numbers

[Jehosephat2k]

The energies of these cosmic rays are measure in EeV (exa-electron volts). 1 EeV ~ 0.16J The most common ones are sitting at around 35 EeV. 35EeV * 0.16J/EeV = 5.6J By comparison, g=9.8 m/s^2. So the weight of a 1 Kg block is 9.8N. Now to lift an object a height h work=mg*h. So, h=work/mg. Puting is 5.6J for the work we get h=5.6/9.5=0.57m So, these photons have enough energy lift a 1 kg block over a half a meter!

Re:

[Jehosephat2k]

Umm, I meant particles, not photons. Duh. Either way, that's alot of energy. One has to wonder what kind of damage these things do when they pass thru your body.

Re:Staggering numbers

[flyingfsck]

The ones that pass through causes no damage.

It is the ones that gets absorbed in your body that cause damage...

Re:

[yusing]

I just went to Google to convert 45 EeV to about 7 watt-seconds.

A little red LED needs .02 amps at 2 volts, or .04 watts. The energy of that one particle would keep it lit for 7/.04 seconds ... nearly 3 minutes!

Re:

[tftp]

Red LED takes 10 mA, green LED 20-30 mA. So in your scenario a red LED will work for 5-6 minutes!

Re:

[Cheapy]

How many library of congresses can they pull over half a Volkswagen?

Re:

[MichaelSmith]

So, these photons have enough energy lift a 1 kg block over a half a meter!

Long ago I read that dust particles from meteors are important to the atmosphere because they nucleate raindrops. I wonder if the heat dumped into the at atmosphere by particles with this amount of energy has an effect on the energy budget of the stratosphere which would be worth modelling.

Re:

[FireFury03]

Long ago I read that dust particles from meteors are important to the atmosphere because they nucleate raindrops. I wonder if the heat dumped into the at atmosphere by particles with this amount of energy has an effect on the energy budget of the stratosphere which would be worth modelling.

ISTR it is believed that cosmic rays may trigger lightning bolts, which are quite important to life.

Re:

[maxume]

The radius of the earth is ~6,400,000 meters, so the sun is generally striking about 128x10^12 square meters(of course, the atmosphere is somewhat larger in profile than this...). 1000 W/square meter is a good enough approximation of solar intensity. So the sun is pushing something like 128 thousand million million watts at the planet. One percent of that is 1,280 million million watts. Someone above said each particle has about 7 watt-seconds of energy. To get the equivalent of 1% of 1 second of sunlight,

Re:

[justthinkit]

What would one of these rays have done to a manned spacecraft on its way to the Moon? Will we ever be able to build a manned vehicle capable of withstanding the impact of radiation received on the way to wherever it is going? And how about the occupants' exposure to such radiation?

Re:

[MandelBro]

There are spacecraft that still function which are well beyond the edge of the solar system by now. Doesn't seem to be much of a problem.

Re:

[maxume]

Good thing your average human is 65kg of mostly empty space, or it might sting a bit to actually get hit by one of these.

Re:

[Jugalator]

The energies of these cosmic rays are measure in EeV (exa-electron volts). 1 EeV ~ 0.16J The most common ones are sitting at around 35 EeV. 35EeV * 0.16J/EeV = 5.6J By comparison, g=9.8 m/s^2. So the weight of a 1 Kg block is 9.8N. Now to lift an object a height h work=mg*h. So, h=work/mg. Puting is 5.6J for the work we get h=5.6/9.5=0.57m So, these photons have enough energy lift a 1 kg block over a half a meter!

So this is where we should head to discover the Higgs particle? ;-)

Comic rays also produce tiny black holes

[holywarrior21c]

http://focus.aps.org/story/v9st3/ [aps.org]

sorry couldn't resist...

[holywarrior21c]

1.????
2. comic rays starts from black holes.
3. comic rays produce mini black holes.
4. go to 1
5. profit!!!

Re:

[Wierdy1024]

You just made an infinite loop in slashcode...

Re:

[mux2000]

I tried it, messed around with the black holes like you said, but I couldn't get to 5. Profit!!!

Help?

Except you forgot about one thing...

[Kagura]

The GZK cut-off [wikipedia.org] prevents such highly energetic particles from reaching the Earth unless they are formed in our galactic neighborhood, so this article only talks about how these particles may have formed, but does not answer why it is that they still have their high energies when they reach us.

Re:

[Gil-galad55]

Except this is a clear violation of the GZK cut-off, as demonstrated by other cosmic ray experiments. This is one of the prime phenomenological manifestations of many theories of quantum gravity, since they all involved some modification of the photon dispersion relation at high energies, neatly circumventing the GZK cut-off, which is based on the good old E^2=(pc)^2+m^2c^4 relation. (This, in the rest frame, is Einstein's famous E=mc^2.) Anyway, the fact that these particles exist, and are clearly extra

Re:

[Gil-galad55]

Hmm, on reading further, I see that the spectrum of the high energy particles is actually consistent with GZK. So, no evidence for QG after all.

Re:

[boot_img]

The GZK cutoff applies only for cosmic rays travelling distances grater than 100 Mpc or so ... these AGN believed to be responsible for the highest energy events are within this distance

Wikipeida link

[cheebie]

I was reading about these particles the other day when I got trapped
in an endless Wikipedia link chain. (Damn you and your font of
interesting information!) Anyway, I'm mostly including it because I
was vastly amused by the nickname they gave the particles.

http://en.wikipedia.org/wiki/Oh_my_god_particle [wikipedia.org]

Re:

[MrConspiracy]

Imagine being hit by protons with (they estimate) the energy of a baseball. It's earned the nickname from that alone, never mind the astrophysics problems.

Re:

[Tablizer]

Imagine being hit by protons with (they estimate) the energy of a baseball. It's earned the nickname from that alone, never mind the astrophysics problems.

Wouldn't it be possible for someone in an airliner to be hit by one of those? Imagine you're reading a magazine aboard a plane and suddenly get smacked in the head by one of these and scream bloody murder and nobody would ever know what hit you. People would think you're going insane.
     

Not a contradiction

[mefein]

There is not really a contradiction between the results demonstrating that supernova remnants (SNR) in our Galaxy are the source of cosmic-rays and this result (suggesting that active galaxies (AGN) are the source). Both are likely correct: that SNR are the source of the lower energy cosmic-rays and that AGN are the source of the ultra-high energy cosmic-rays.

It had always been expected that the lower and higher energy cosmic-rays would have different origins. At lower energies, the magnetic fields in SNR are strong enough that the charged particles are magnetically trapped and rattle around inside the SNR continuing to be accelerated to higher and higher energies in the process. Once they attain a high enough energy, they are no longer contained in the SNR and escape (and thus do not gain more energy). The very high-energy cosmic-rays seen by Auger are much more energetic than anything in our Galaxy can produce. Active galaxies, which are known to accelerate particles very efficiently fueled by the accretion of matter onto a supermassive black hole had always been a leading candidate for the sources of the ultra high energy cosmic-rays. It is an outstanding result.

Particles accelerated to energies 10^8 higher...

[RudeIota]

"The exact mechanism of how particles get accelerated to energies 100 million times higher than achievable by the most powerful particle accelerators on Earth is still unknown."

Now... Let's just hope it STAYS that way...