Most Powerful Cosmic Rays Come From Galaxies Far, Far Away (space.com) 97
A new study finds the highest-energy cosmic rays to bombard Earth come from galaxies far, far away. Space.com reports: The sun emits relatively low-energy cosmic rays. However, for more than 50 years, scientists have also detected ultra-high-energy cosmic rays, ones far beyond the capability of any particle accelerator on Earth to generate. One way to discover the origins of ultra-high-energy cosmic rays is to study their directions of travel. However, ultra-high-energy cosmic rays only rarely strike Earth's atmosphere, with one hitting any given area about the size of a soccer field about once per century, the researchers said. In order to detect ultra-high-energy cosmic rays, scientists look for the spray of electrons, photons and other particles that result when ultra-high-energy cosmic rays hit the top of Earth's atmosphere. Each of these showers contains more than 10 billion particles, which fly downward in a disk shaped like a giant plate miles wide, according to the statement. Scientists examined the sprays from ultra-high-energy cosmic rays using the largest cosmic-ray observatory yet: the Pierre Auger Observatory built in the western plains of Argentina in 2001. It consists of an array of 1,600 particle detectors deployed in a hexagonal grid over 1,160 square miles (3,000 square kilometers), an area comparable in size to Rhode Island. A connected set of telescopes is also used to see the dim fluorescent light the particles in the sprays emit at night.
The researchers analyzed data collected between 2004 and 2016. During these 12 years, the scientists detected more than 30,000 ultra-high-energy cosmic rays. If ultra-high-energy cosmic rays came from the Milky Way, one might perhaps expect them to come from all across the sky, or perhaps mostly from the direction of the supermassive black hole at the galaxy's center. However, the researchers saw that ultra-high-energy cosmic rays mostly came from a broad area of sky about 90 degrees away from the direction of the Milky Way's core.
The researchers analyzed data collected between 2004 and 2016. During these 12 years, the scientists detected more than 30,000 ultra-high-energy cosmic rays. If ultra-high-energy cosmic rays came from the Milky Way, one might perhaps expect them to come from all across the sky, or perhaps mostly from the direction of the supermassive black hole at the galaxy's center. However, the researchers saw that ultra-high-energy cosmic rays mostly came from a broad area of sky about 90 degrees away from the direction of the Milky Way's core.
Long long ago, far far away (Score:2)
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Or the explosions from the Death Stars. After all, those things were holding on to a lot of power that had to go somewhere...
If you look through really really really powerful telescopes would we see a planet being altered to consume the full power of a nearby sun?
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Or the explosions from the Death Stars. After all, those things were holding on to a lot of power that had to go somewhere...
Every Death Star contains a clone of Donald Trump in its core. When a "Fire!" command is received, the Principal Fire Command Engineer takes a lighter and pretends to put fire on Donald Trumps hair. The Death Star core bundles the concentrated anger of the Donald into a laser beam.
This is what actually happens inside of a Death Star.
I'm not saying it's aliens... (Score:1)
...but it's aliens.
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They are not Cosmic Rays... they're Midi-Chlorians.
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That's ridiculous...in order to be detectible at this distance the beam would have to be incredibly coherent and collimated, like some kind of super-laser.
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Cave drawings.
'nough said.
Obvious retort (Score:2)
Satan did them to confuse you and test your faith.
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Who many version is there of the bible again?
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Who many version is there of the bible again?
To be fair, if the bible is wrong that wouldn't mean evolution is real. It would just mean the bible is wrong.
/ just playing devil's advocate... of course evolution is real.
Re:PROOF that evolution is a HOAX. (Score:5, Insightful)
Nice nic for that comment.
The fundamental* mistake is to think of the Bible as any sort of science or history. Both religious whackjobs and atheist evangelists keep repeating that mistake. That's not the kind of book the Bible is: it's not a book about "how the world is", it's a book about "how to live in the world".
Seeing the assholes and idiots on both sides (well, mostly the religious side) keep on about stuff like evolution as if it had any bearing whatsoever on the "truth" of the Bible gets really old. It's a book about psychology and social organization, and the stories therein are true or false based on whether they give good advice.
*I'm sure you see what I did there.
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There's no evidence that human psychology has changed in thousands of years.
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Human like footprints have been found that are over 6 million years old. To record history you have to be able to write.
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http://tinyurl.com/yblxksla [tinyurl.com]
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Venus of Willendorf [wikipedia.org].
Evolution probably is not 100% accurate (Score:2)
Why specifically the Christian version of the Bible and not any of the texts that pre-date it or any of the more recent texts? How do you know the Mormons aren't the ones who got it right, they are Christians (by their own definition) yet have a dramatically different view on history than you do.
hypothesis (Score:1)
Perhaps the spherical ("planetary") component of the galaxy has a large dipole magnetic field, which could cause an acceleration of charged particles which impinge upon the disc portion, thereby mimicking "intergalactic" cosmic rays.
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The galaxy does have a magnetic field, which is rather chaotic rather than dipole shaped and weighs in at the micro-gauss level. There are a number of different ways to measure this both in our own galaxy and in other similar galaxies.
To get charged particles of these energies (> 10^20 eV) to bend in less than a galactic radius, you need a lot more B than that, and that large a B is not seen.
Not the Distance, but the Time... (Score:4, Interesting)
When dealing with astronomical observations of this type, we accept that the observations we are making could be millions or even billions of years old, based on the distance from which the phenomena originate. OK, so: old data.
We are also told by physicists that our universe started with a "big bang", a state and point in time at which the state of our universe was so energised that the sub-atomic particles we take for granted today [never mind atoms and molecules] did not exist - because the universe had not cooled sufficiently.
So if you extrapolate this facts, don't they suggest that it stands to reason that, the further away in distance [and thus the further back in time] that we look, the higher the energies we would expect to observe. Everything else is [just / subject to] entropy.
I'm not sure where Occam's Razor would swing across this story, but suspect the explanation - whatever it is - will be a simple one.
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One issue with Occam's razor is that what may be obvious and simple to one person may not be to another. Hence 2 different people will come up with what they think to be a perfectly logical and simple explanation.
That means that some will actually think this is Star Wars.
I may be that person...
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Truth be told, it satisfies both assumptions of "a long, long time ago" AND "in a galaxy far, far away".
Re:Not the Distance, but the Time... (Score:5, Informative)
We are also told by physicists that our universe started with a "big bang", a state and point in time at which the state of our universe was so energised that the sub-atomic particles we take for granted today [never mind atoms and molecules] did not exist - because the universe had not cooled sufficiently. So if you extrapolate this facts, don't they suggest that it stands to reason that, the further away in distance [and thus the further back in time] that we look, the higher the energies we would expect to observe. Everything else is [just / subject to] entropy.
No, because the high energies from that time has cooled down to what we predicted and observed as the Cosmic Microwave Background.
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The initial energy has decayed to something like 3 kelvins nowadays, except in very small spots. However, some energetic events (quasars, at least) did happen when the Universe was younger.
Yes, but can't explain Cosmic Rays (Score:5, Informative)
So if you extrapolate this facts, don't they suggest that it stands to reason that, the further away in distance [and thus the further back in time] that we look, the higher the energies we would expect to observe.
To get to the energies of cosmic rays you have to go back to before 10^-13 s after the Big Bang. Back then the Universe was incredibly small and incredibly dense. So dense and energetic that everything, even things like neutrinos, were colliding and interacting with everything around them. This meant that everything was roughly in thermal equilibrium and had comparable energies.
By the time than the charged particles responsible for cosmic rays the energy and density of the universe would have been much, much lower since it would require photons to decouple first which happened 380,000 years after the Big Bang. The result is that there is no way that a Cosmic ray, as a charged particle, can get its energy directly from the Big Bang.
It could get it indirectly if there were some high mass, exotic and as yet undiscovered particle which was created in the Big Bang and which decays with a lifetime of billions of years or which might annihilate with itself to create these particles. This is one possible way to detect Dark Matter but it is extremely unlikely (impossible without even more new physics) that this would provide enough energy to explain high energy cosmic rays.
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Very well put! Makes me miss the good old days of slashdot, when posts like this were more common, and the trolls were more energetic too.
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To get to the energies of cosmic rays you have to go back to before 10^-13 s after the Big Bang. Back then the Universe was incredibly small and incredibly dense. So dense and energetic that everything, even things like neutrinos, were colliding and interacting with everything around them. This meant that everything was roughly in thermal equilibrium and had comparable energies.
The obvious explanation is that they bounced off the edge of the universe, God yelled "brick!" and the rays were flung back at us via blackhole. We're part of a REALLY big game of cosmic basketball. ;)
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Frankly m now on (Score:5, Funny)
If I'm ever asked "how big is Rhode Island?", I'm going to say "it's roughly the size of the Pierre Auger Observatory in Argentina".
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How many blue whales is that?
Exactly?
Blue whales are a unit of weight, not area. Get your units right.
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Okay, then, how many square smoots is that?
*sigh* Are those standard or imperial smoots?
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Jar-Jar, for example.
I would like to imagine Jar-Jar being bombarded by high energy cosmic rays.
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So... he will be "pewnished"?
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I'll drink to that!
-Jar Jar fan
90 Degrees (Score:1)
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If true, all such matter would have the same change / trajectory to it.
It means they come in on a completely unexpected angle, the people studying them aren't stupid.
Comparatively speaking the gravity of the galaxy is either pathetic, or so strong you end up caught in it's whirlpool. There's basically nothing that could ever do what you suggest, no matter how heavy or non-existent the particle (not that the mass of a particle, or absence of mass, has much to do with how much gravity affects it - gravity is
Re:90 Degrees (Score:5, Insightful)
That doesn't mean they came from elsewhere, it would also sync up really well with them coming from the blackhole in the center of our galaxy and being curved back inward by the gravity of the whole galaxy - sort of a galactic-scale particle accelerator. (Like the field lines of a magnet.)
Or instead of "really well", not all in any way, shape, or form. You have no idea of the physics involved, typing words is not a physical analysis.
The galactic escape velocity for an iron atom (a typical heavy cosmic ray particle) is about 10^5 eV. All of the cosmic rays under discussion have energies greater than 10^19 eV, or 100 trillion times more energetic than the galactic escape velocity energy.
The galactic magnetic field is much better at holding on to cosmic rays, but cannot confine them above an energy of 10^18 eV or so. Which is why the researchers are studying extragalactic cosmic rays with energies above 10^19 eV. They know these cannot be confined to the Milky Way.
If hundreds of professional astrophysicists are devoting their careers to studying a problem, you can be sure that nothing you come up with off the top of your head, without knowing anything about the subject, is going to have any merit.
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If hundreds of professional astrophysicists are devoting their careers to studying a problem, you can be sure that nothing you come up with off the top of your head, without knowing anything about the subject, is going to dissuade them from following the money.
Yeah, cause if I'm a well educated, intelligent person with a large range of technical skills in both software and hardware looking to make lots of money, I'm definitely going to go into astrophysics.
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Undoing wrong moderation. Nothing to see here, move along.
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I know this type of comments, but OMFG, I just don't understand this kind of repulsive anti-intellectualism. Being a researcher require extremely long studies, and the pay is not particularly great. Any physicist could have probably spent half as long in university to get a much better paying job in finance or something to that effect. I think these people are driven more by their interest in their field of study than by any profit motive, yet they get spat on while people like Jeff Bezos and Steve Jobs are
Re:90 Degrees (Score:4, Funny)
If hundreds of professional astrophysicists are devoting their careers to studying a problem, you can be sure that nothing you come up with off the top of your head, without knowing anything about the subject, is going to dissuade them from following the money.
So true. It's simply disgusting that there is this cabal of union bosses, Leftist billionaires and government bureaucrats which is conspiring to further fund the *myth* of extragalactic cosmic rays, all in an attempt to push their agenda of redistribution of wealth and punishing Job Creators.
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If hundreds of professional astrophysicists are devoting their careers to studying a problem, you can be sure that nothing you come up with off the top of your head, without knowing anything about the subject, is going to dissuade them from following the money.
So true. It's simply disgusting that there is this cabal of union bosses, Leftist billionaires and government bureaucrats which is conspiring to further fund the *myth* of extragalactic cosmic rays, all in an attempt to push their agenda of redistribution of wealth and punishing Job Creators.
Actually, it's a conspiracy of the Technocracy which is attempting to alter the consensual reality to fit their physical narrative.
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To follow the money (which astrophysicists typically don't make), a scientist will try to establish a reputation as a top researcher, because they get the smallish bucks, much better than other astrophysicists. Reputations are not made by confirming what other people are saying, but rather by contradicting them and getting away with it. If someone cares deeply about money, that person isn't going to become a scientist.
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I think that "smack down" was a bit harsh. He's suggesting an idea -- and while I thought it had little merit, we are talking about one eV in magnitude difference between nonsense and plausible.
Normally, it's true to assume the random person with 5 minutes of bright ideas has not thought of something that scientists who've devoted their careers to the topic. Most notably, people pointing out the sun as a heat source that climatologists may have not considered, come to mind.
It's considered traditional to ref
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but that does *not* necessarily mean they were generated outside of the Milky Way
Two things affect this assumption: One. If such high energy cosmic rays were produced in any great quantities within the Milky Way, the odds are that we would be able to observe their source and make some guesses about the mechanism of their generation. These hypothetical close-in sources would produce observable cosmic ray 'hot spots' in their distribution pattern. Two. The distribution of particles suggests that they are more likely attenuated by the matter in the Milky Way's disk and core than produced t
Not gravity, magnetic fields (Score:3)
So for this result, I presume that they must have ruled out the possibility that these rays are being bent back towards us by the galactic magnetic
How can this be new? (Score:5, Interesting)
Way, way back in the 1980s as an Honors CS student I wrote some code on an old DG Nova to analyze cosmic ray bursts for the Physics Dept (Uni Adelaide). They had several detectors, hooked into a CAMAC crate, and could measure the time difference between the receptors, and thus the direction of the burst, or at least where the cosmic ray hit the atmosphere, and by also looking at distributions work out roughly which direction the original ray came from.
Some of them are charged particles and so do not travel in straight lines, which complicates it. I just did the programming, not much to do with the physics, but I would have thought this would be old news.
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You may be confusing two different things, the result of archaic language; Cosmic Rays are as a descriptive term as Atom Bombs once was.
Charged Cosmic Particles, from Protons up to Iron, have been detected. That nothing heavier than Iron has been found rules out all but Stellar Fusion formation. The Bevatron was used to first characterize this, and in fact, they had an "Eye Flash" Station on top of the Shielding where one could peek at the synthetic ones. It was called "Eye Flash" due to direct Human Detect
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Hey - I was at Adelaide Uni in the 2000s. I think I learned enough to answer your question.
All of the cosmic rays (probably) are charged particles, and do not travel in straight lines. A detector array can work out the direction a cosmic ray came from, to within about a degree, but that doesn't help much when this arrival direction could be 90 degrees away from the cosmic ray's source.
The low-energy ones travel in very curved paths, and their arrival directions are effectively fully randomised. The high-
Re:How can this be new? (Score:4, Informative)
I did my MSc across the Tasman in New Zealand in 1988 on the JANZOS cosmic ray experiment. We had Cerenkov telescopes detecting particles of about 10^12 eV, and particle detectors for showers from primary particles of about 10^15 eV. (i.e. high enough energy that the cosmic ray shower reached ground level.)
We were well aware of the problem of charged particles traveling straight. A few cosmic rays (from memory, about 1%) are gamma rays, which do travel straight. The problem is that we couldn't tell from the shower whether the primary particle was a gamma ray, so you're looking for a directional signal of 1% against a background noise of 99%.
There were suggestions at the time that Cerenkov telescopes with better imaging than ours could perhaps distinguish gamma ray induced showers, and for the higher energy showers you could use underground muon detectors, because hadron-triggered showers produced more muons. I haven't followed cosmic ray astronomy since then, so I don't know the current state of the art. I found it frustrating to be in a field where you struggle to convince others (and possibly yourself) that you've seen anything at all other than noise.
The AC from Adelaide in the 2000s replying to your message says that at these super-high energies you can get direction information because they are too high energy to be deflected much. It makes sense that this would be the case at sufficiently high energy, although I don't know what 'sufficiently high energy' would be.
I did maximum likelihood analysis on reconstructing the direction of the cosmic rays from the particle detectors. I had a little legacy code to start with, which was in Fortran 77, so that is what I used. Happily, I have never had to use Fortran ever again.
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Oh, wow - the field's come on a bit since then! The Cherenkov telescopes operating at around 10^12 eV can now discriminate between gamma rays and cosmic rays fairly reliably, just from the shape of the shower, without needing muon counters as a discriminator. There are three big Cherenkov observatories at present - MAGIC, HESS and VERITAS - which have been very successful at mapping high-energy gamma-ray emission.
Gamma rays do provide directional information, but only at low-ish energies (~< 10^14 eV).
Higher Energy, Reconstruct Original Ray (Score:2)
Huh? (Score:1)
Isn't it fairly obvious that weak cosmic rays not coming from a nearby source must actually be strong cosmic rays if they are coming from a far away source?
extreme energy cosmic ray (Score:3)
Wikipedia tells me that extreme energy cosmic rays (>5x10e19 eV) are limited to about 160 million light years.
Trouble with astronomy is that this can be close or far depending on how you squint when you look at it :-)
Also google the oh-my-god particle which was estimated at 3x10e20 eV.
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The description I read was the energy of a baseball going forty miles an hour. We haven't found one in Bob Feller or Nolan Ryan territory yet, I guess.
Seems intuitive (Score:2)
If the most powerful cosmic rays came from our own sun, we probably wouldn't be here. DNA-based life anywhere could probably say the same.
I choose to believe... (Score:4, Funny)
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I choose to believe these are the echoes of epic battles of ancient galaxy-spanning civilizations fighting to extinction over the correct pronunciation of "GIF" and whether emacs or vi is the superior editor.
If they fight that hard over "GIF" it's a good job no one asked if they were iPhone or Android.
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And, obviously, they use vim.
Cosmic rays (Score:2)
Not far away, sorry Star Wars fans (Score:3)
They are probably from "nearby galaxies" based on the direction clustering. This would also imply the rays dissipate or weaken over distance, or else their source should appear roughly uniform across the sky, because "lasting" rays would otherwise be arriving from galaxies all over the universe in all directions. Although red-shifting (expansion) may also account for some distance-based weakening. Magnetic fields, ions, and dust in stuff in between could also weaken the rays over time. The cause(s) of the weakening is only speculative at this time.
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Since it's just about impossible to actually test the Greisen-Zatsepin-Kuzmin effect over long distances, models, indirect observations, and extrapolation of lab tests are used; but still imperfect. Perhaps I could have used a different description, but it's not far off.