Origin of Cosmic Rays Confirmed 155
cats-paw writes in with news of research that seems to confirm and support current theories of how cosmic rays are created. The prevailing thinking has been that cosmic rays are generated in the regions where supernovas' shock waves interact with the interstellar medium. The new research used the variability in X-ray emissions from a supernova remnant to estimate the strength of the magnetic fields present in that environment. The results lend support to the possibility of protons and nucleii being accelerated in supernova remnants to energies of 1 PeV (10^15 eV) and beyond. Here is the abstract from Nature.
Synopsis (Score:3, Funny)
Good! (Score:2)
compressed synopsis (Score:2, Funny)
d'oh (Score:5, Funny)
Oh, great, now that everyone knows how to make them, the Fantastic Four are going to be up to their eyeballs in supervillainry.
When I punch 10^15 eV into Google... (Score:3, Funny)
Re:When I punch 10^15 eV into Google... (Score:5, Informative)
Re:When I punch 10^15 eV into Google... (Score:5, Informative)
So, imagine the energy level to be 8-9 ORDERS OF MAGNITUDE (or around a billion times) more energetic than a nuclear fission chain reaction.
Re: (Score:3, Informative)
Re: (Score:2)
Re: (Score:2)
Re:Paco (Score:2)
Re: (Score:1)
Re:When I punch 10^15 eV into Google... (Score:4, Informative)
The only way we currently have of energizing protons to even a measurable fraction of energy like this is in particle accelerators. They're spun around in magnetic fields to faster and faster speeds, gaining mass and energy or energy as they go. That energy ultimately comes from some kind of generator and the fuel it uses.
Eventually, they're slammed into a stationary target or a particle going the other way in the same accelerator. The more mass and energy the particles have accumulated, the more exotic the reactions that occur when that happens. The point of the experiment is to funnel a massive amount of fuel energy into one spot and see what happens when it goes 'boom'.
The super-energetic cosmic rays use the magnetic shockwave created by a Supernova to achieve about the same effect. Rather than being spun around a particle accelerator, they're being spun around the coiled loops of magnetic flux created when a super-massive star decides to disembowel itself.
So, to get anywhere near the ability to create one of these, let alone some kind of ray weapon utilizing them, we'd need a particle accelerator larger than the Sun (or able to churn out more energy than the Sun does). By the time we were able to build one, we'd be dismantling planets by other means anyway.
Re: (Score:1)
Also, try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
Woah.
Re: (Score:2)
Re: (Score:2)
Re:When I punch 10^15 eV into Google... (Score:5, Informative)
Some of them apparently violate a theoretical limit on the energy of a particle that has traveled a long way across the universe... leading to the question of where exactly they come from.
Re: (Score:3, Funny)
50 joule proton... Almost makes you suspect the gods made a mistake with their pointer arithmetic. Either that or someone crossed the streams.
Re: (Score:2)
Re: (Score:2)
This is a really interesting topic called the GZK cutoff. Basically, you expect that a particle with sufficiently high energy could scatter off of the microwave photons in the cosmic microwave background that permeate the entire universe, left over from the Big Bang billions of years ago. The particles have so much energy that when they hit the little photon, they pop off an entire pion (mass about a 15% of the proton). Since the universe is dense with such photons, you'd think these high-energy particles would just continuously pop off pions until their energies are below the GZK cutoff.
And recent high-statistics experiments verify the existence of the cutoff, refuting earlier suggestions that there were anomalously high-energy cosmic rays: Observation of the GZK Cutoff by the HiRes Experiment [arxiv.org]
Hmmm... interesting. So is there any current theory that could plausibly explain the detection of these high-energy cosmic rays? Are they thought to be just measurement anomalies?
Is the GZK cutoff truly isotropic like the CMBR, or are there magnetic or other interactions that can disrupt it?
Re:When I punch 10^15 eV into Google... (Score:5, Informative)
~Ben
Re: (Score:2)
Re: (Score:2)
~Ben
Re: (Score:3, Interesting)
6x10^20 J. That, amazingly, equals the total enery production on earth in one year. http://en.wikipedia.org/wiki/World_energy_resources_and_consumption [wikipedia.org]
Re: (Score:2)
Awesome.
Re:When I punch 10^15 eV into Google... (Score:5, Funny)
Re:When I punch 10^15 eV into Google... (Score:5, Informative)
So, it takes 4.1868 joules to heat one cubic centimeter of water (one gram of water) one degree centigrade. So 0.00160217 joules is enough to heat one gram of water 383 microdegrees.
So, yes, in one sense that's not very much energy.
But, if you're going to scale the mass up, you should scale the energy up. So, it's one proton that has that much energy. The gram of water has approximately 6.02*10^23 proton masses. If every proton mass in the gram of water had that much energy, it would be equivalent to that gram of water being heated by 2.3*10^20 degrees. This is 230 trillion trillion degrees (yes, that's two trillions).
I hope this gives you a sense of the scale involved here.
When you have a single proton with enough energy to make a measurable difference in the temperature of a gram of water, you are talking an amazingly huge amount of energy.
Re: (Score:2)
Re: (Score:2)
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Re: (Score:1)
[OT] Nitpicking summary (Score:4, Insightful)
So this research confirms... supports...well lends support to the possibility. Care to soften it further?
Re: (Score:2, Informative)
Re: (Score:1)
Re: (Score:2)
Re: (Score:3, Interesting)
Re: (Score:2)
Re: (Score:1, Interesting)
For instance, a relatively low density plasma can support a weak electric field. Consistent with this, a low amplitude
Re: (Score:2, Interesting)
Maybe I'm wasting my time. It seems clear that "alternative cosmologies" means the electric universe theory, which doesn't make any useful, testable predictions.
Re: (Score:2)
It sounds as if you're asking me to explain what a z-pinch is. There are plenty of plasma physics textbooks that do as much. One of the EU Theory advocates in fact, Anthony Perratt, wrote his own such plasma physics t
Re: (Score:1)
Re: (Score:2)
Cosmic radiation coming this way?! OMG! It's the rise of the Silversurfer!
Re: (Score:2)
Re: (Score:2)
You know, in plasma cosmology, the theories associated with the creation and sustenance of stars cannot be so easily picked apart from the cosmology itself. Within plasma cosmology, stars form as a natural byproduct of electrical plasma behavior that we observe within the laboratory. The continued operation of the star is then subsequently a function of the star's plasma surroundings. Within plasma cosmology, there is no
Re: (Score:2)
According to the creation museum in Kansas (Score:5, Funny)
Re: (Score:2)
Re: (Score:1)
Everyone loves a good RPG from time to time.
The big guy might like living like a college kid, drinking beer, partying.
Then at night, boom, hes a super hero fighting crime, getting wimmins.
Fluffy clouds and angels might get old after a bit, ya know?
Re: (Score:2)
Well that's almost true. Actually he sub contracts the job to Chuck Norris.
Re: (Score:1)
Re: (Score:2)
-Mike
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
a good science post? (Score:5, Insightful)
I think if I was not an experimentalist, I would want to study this area of physics (supernova observation). Going through the steps of a supernova exposes you to some of the most amazing physics we know of, and this research only adds to that.
Re:a good science post? (Score:5, Funny)
Re: (Score:2)
Well done.
Re: (Score:2)
Re: (Score:2)
yes but.. (Score:1)
nuclei, NOT nucleii (Score:5, Informative)
"nucleus" -> "nuclei"
"radius" -> "radii" (because there's already an "i" before the "us")
Re: (Score:2, Funny)
Re: (Score:1, Funny)
Re: (Score:3, Funny)
For George Bush it's "nuculi", though "nuculei" sounds cooler.
Re: (Score:1, Offtopic)
Re: (Score:2)
Summary incorrect... (Score:1)
Re: (Score:1)
Re:Summary incorrect... (Score:4, Interesting)
Additionally, the abstract says their research "provide[s] a strong argument" for a theory. I suppose these statements are way too hard-line for Real Science. Sheesh. These are people who know very well they're doing inference rather than deduction - including the submitter! - and you take them to task for jumping to conclusions.
You say:
The hypothesize/predict/experiment cycle isn't nearly as boolean as you make it out, even though we teach it that way in school.
If a result doesn't disprove a theory, it actually increases its probability among other possibilities. Bayesian statistics models this quite well, and scientists think about it that way but without such a rigorous foundation. For example, in all forces, we've measured the differential relationships among position, velocity and acceleration to ridiculous precision. Doesn't this increase the probability that we've got it right? In this area, if there's a conflict between predicted and expected outcomes, we regard the explanation that the theory is wrong as the less probable one - much less probable.
Part of the problem is classical statistics. Null hypotheses and tests against them are kludgy nonsense, everyone knows it, and everyone has their own way of doing it "properly". (Think about it this way: Pr(null hypothesis), where the null hypothesis has a continuous component - and this is done all the time - is ZERO.) Doing inference without priors is a misguided attempt at objectivity. These mindsets are well-preserved in scientific philosophy, and they've got to go. Nobody actually thinks about real inference the classical way. It'd be ridiculous to try it on any hypothesis of moderate complexity.
Very, very hot (Score:2)
Re: (Score:3, Funny)
Re:Very, very hot (Score:5, Funny)
But how many Libraries Of Congress On Fire is that?
Re: (Score:1)
Because of this the LoC is also the most fundamental of all units.
The Planck units therefore must replaced!
Planck Libraries of Congress, PLoC!!
Re: (Score:1)
Billions and billions..........
</Sagan>
Re: (Score:2, Informative)
While we're at it, a million millions is one trillion.
No offense, but geez, call it what it is.
Roasting Times (Score:4, Funny)
Re: (Score:3, Informative)
Re: (Score:2, Informative)
So, if I need to cook a turkey, how long should I leave it in at 6,446,700,000,000,000,000 degrees?
0.0000000003186 seconds
Interesting... (Score:1)
Scientists wish for its egg...
Does haiku mod up?
Re: (Score:1)
Re: (Score:2, Funny)
No No No No No No No
No No No... Maybe
Ya Know..... (Score:2, Funny)
Re: (Score:2)
In Soviet Russia... (Score:1, Troll)
Or perhaps ... (Score:2)
Re: (Score:1)
Re: (Score:3, Funny)
Oh My God Particle (Score:2, Interesting)
The poster child of uber-freaked out cosmic rays is a crazy bugger [wikipedia.org] detected in 1991 that had an energy of 3.2 x 10^20 eV. One scientist compared it to dropping a brick on your toe! Cosmic r
Re: (Score:3, Informative)
Maybe at 1AU, but out beyond the magnetosphere that isn't true.
For what it's worth, the many flavors of galactic cosmic rays you mention is pretty much the periodic table. While true there are a variety of ways to accelerate a charged particle, there are not that many known ways to get them to those energies that don't stick out like sore thumbs (which is why supernovae were always the best candidates). For the galactic cosmic rays, at least one of the methods must
Aunt Petunia's favorite nephew (Score:1)
Re: (Score:3, Funny)
Of course, at this energy the impact of the proton with the lead would result in a lot of neutrons being released, and lead doesn't stop those very well. Maybe if you made some sort of composite-sandwich with lead followed by neutron moderating material and a neutron absorber. Of course, then the neutron-activation of the absorber would cause gamma-ray emissions, so you'd need another layer of lead, possibly followed by
Olbers Anti-Paradox? (Score:1, Interesting)
Re: (Score:3, Informative)
But Olber's paradox says that if the universe were infinitely large and infinitely old, then no matter where you looked you'd eventually see the surface of a star, so the sky wouldn't just be bright: it would be be sun-bright,
Huh? No, I just farted. (Score:1)
Wow (Score:1)
Re:God did it! (Score:5, Funny)