What is Cosmic rays: Definition and 64 Discussions

Cosmic rays are high-energy protons and atomic nuclei that move through space at nearly the speed of light. They originate from the sun, from outside of the solar system in our own galaxy, and from distant galaxies.Cosmic rays were discovered by Victor Hess in 1912 in balloon experiments. Direct measurement of cosmic rays, especially at lower energies, has become possible since the launch of the first satellites in the late 1950s. Particle detectors similar to those used in nuclear and high-energy physics are used on satellites and space probes for research into cosmic rays. Upon impact with the Earth's atmosphere, cosmic rays can produce showers of secondary particles that sometimes reach the surface.
Data from the Fermi Space Telescope (2013) have been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernova explosions of stars. Active galactic nuclei also appear to produce cosmic rays, a physical reality ascertained as true, based on observations of neutrinos and gamma rays from blazar TXS 0506+056 in 2018.

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  1. Sciencemaster

    I Incorrect units when calculating cosmic ray muon flux

    I recently performed an experiment that involved using a cylindrical scintillator to detect cosmic ray muons by observing the amount of particles that decayed within 20 microseconds over a long period of time. I'd like to use this to find the flux of muons at my scintillator so that I can...
  2. Zuzana

    A GZK Limit: Exploring Cosmic Ray Energies Beyond 10^20 eV

    Hello, I would like to ask, why there cannot be detected cosmic rays with energies higher than ~ 10^20 eV, i.e. beyond the GZK limit? Thanks a lot in advance for the answer.
  3. S

    I Are some cosmic rays iron nuclei?

    I had thought that cosmic rays were all protons, but this article says sometimes it's iron. https://getpocket.com/explore/item/let-s-colonize-titan
  4. S

    I Are cosmic rays only neutrinos?

    I had thought that cosmic rays were protons, but this NY Times article seems to say that cosmic rays are neutrinos: https://www.nytimes.com/2021/03/30/science/neutrinos-lake-baikal.html
  5. T

    B Where do the electrons go? (in stellar nuclear fusion)

    I have to give a presentation about natural Radiation and I am very happy about it because it includes Astrophysics. I want to explain to my audience how the stars produce cosmic rays. I thought about explaining to them how nuclear fusion and that kind of stuff works but then I realized that I...
  6. Endeavour13

    I Suggestion for resources about cosmic rays

    I am a Junior UG student in Physics. We have an introductory course on astrophysics. It includes modules on cosmic ray and magnetic field in galaxies. I have a basic acquaintance with QM (up to Hydrogen atom problem). I also had a course on basic particle physics. (Very rudimentary. Mainly intro...
  7. E

    I Cosmic Rays could reveal if we're actually living in a simulation?

    https://www.businessinsider.com/we-may-be-living-in-the-matrix-2013-11 can an experiment with cosmic rays prove or disprove the hypothesis of simulation?
  8. S

    Has a change in the cosmic rays hitting Earth been causing Global Warming?

    I found this link off of a politically charged website (of the persuasion to deny that Global Warming exists), so I am apt to be skeptical. (The website is hosted at the Northern Marianna Islands, making me even more suspicious.)...
  9. mjda

    I The Confinement Radius of a Cosmic Ray (Galactic vs. Extra-galactic)

    If we want to show whether or not a specific Cosmic Ray particle is confined to our galaxy we must use the Larmor radius (relativistic version), r = γmc / qB Considering a 10^14 eV proton and assuming the galactic magnetic field strength is 10^−11 T, show that the particle is confined to the...
  10. P

    A Notes on Cosmic rays - wave interactions in plasmas

    Dear community, I am Pedro de la Torre, now doing my PhD on Cosmic ray propagation. Now, I have started to study reacceleration due to interactions of CR with plasma waves. My problem is that I do not find neither a good book or any kind of review with a detailed demonstration on the...
  11. f95toli

    A Info about cosmic rays affecting microchips

    Sorry for the vague title; I couldn't think of a better one. I have been looking for information about how frequently one could expect cosmic rays (of all types) to hit and be absorbed by a piece of silicone (say 5x5x0.5 mm3) at the surface of the Earth. But haven't had much success. I know...
  12. W

    B Cosmic Rays Charge: Expect Reissner-Nordstrom Black Holes?

    Cosmic rays are overwhelmingly positively charged. Hence, whatever is emitting them must be building up an enormous negative charge. So should we expect to see highly charged Reissner-Nordstrom black holes out there? Perhaps even near extremality?
  13. Suppaman

    B Cosmic Rain: Exploring the Mysteries of High-Energy Particles

    I was just reading the article about “cosmic rain” here and they talk about these very high energy particles striking a detector. But as I understand things, these have to be waves, not particles, put up a double slit and these things will go through both as waves (and since they do not know...
  14. AdrianMachin

    A problem regarding the electric potential of an electron

    Homework Statement There is a sample problem in my physics textbook (Fundamentals of Physics, 10th Edition by David Halliday and others) which has some confusion in it for me. Please take a look at the snapshot I took, in the attachments. Homework Equations 3. The Attempt at a Solution [/B]...
  15. RyuuJin

    A Distrubution of cosmic rays

    Hey guys! I am trying to simulate distribution of cosmic ray particles, which change their trajectory due to planet's magnetic field (no atmosphere; dipole approximation). I tried considering protons with non-relativistic velocities, falling on an Earth-like planet, which has rotational axis...
  16. Dr Wu

    B Cosmic Rays: How Fast Do They Travel?

    I understand that cosmic rays can (and do) propagate through space extremely rapidly. But just how rapid, I wonder? (For reasons I know not, and despite having googled questions like "Speed of cosmic rays" and "How fast do cosmic rays travel?", I keep drawing a blank. I gather that subatomic...
  17. UHECRon

    A Photon densities within galtactic disc compared to CMB

    I am interested in what the average photon densities are within galactic environments due to non CMB sources. In extra galactic environments, the CMB certainly dominates, however as you enter more dense and luminous areas (e.g. , the galactic disc) broad spectrum photon densities from local...
  18. U

    A Calculating the ionization rate in the Interstellar medium?

    I hope putting this in the high energy section is the right section (if not, please let me know which would be more appropriate!) I felt this was appropriate since the work I am doing is high energy astrophysics. So I'm doing some research this summer, and my tasks were to take some data...
  19. U

    A Ionization Rate for Cosmic Rays, given the CR spectrum

    Hi all, so I am working on a presentation. What I have done so far was to calculate the cosmic ray spectrum (so given some data from Voyager 1 and PAMELA, I found the intensity as a function of the energy, in units of m^-2 (sr s MeV)^-1. Given this function, which is essentially J =...
  20. B

    B "Without Earth's atmosphere, cosmic rays would be lethal"

    In the episode Unafraid of the Dark in Neil deGrasse Tyson's series Cosmos, Tyson says the following: "Hess had discovered cosmic rays, showers of subatomic particles that crisscross the universe at nearly the speed of light. Without the shielding effect of the Earth's atmosphere, they would be...
  21. Dotini

    I Intensifying Cosmic Rays

    The following article is from the January 28, 2016 edition of Spaceweather.com: INTENSIFYING COSMIC RAYS: For the past year, neutron monitors around the Arctic Circle have sensed an increasing intensity of cosmic rays. Polar latitudes are a good place to make such measurements, because Earth's...
  22. H

    Cell phones used to detect cosmic rays worldwide

    There are now more active cell phones than humans. (?) The camera lenses of cell phones can detect cosmic rays. An app has been created that stores such detections in a data base. The app has been used in Iceland, Uzbekistan, and Uganda. There is no apparent practical use, it is for...
  23. Michel

    Density LHC vs. Cosmic Rays

    Hello, I have a question regarding the density of the LHC vs. Cosmic Rays and why the big difference doesn't matter for particle research? As a reference we look at ultra-high-energy cosmic rays which are perfect for 'one on one' collisions, but isn't 'dosage' also a parameter to consider? --...
  24. P

    Reflect Cosmic Rays: Materials for Mirrors

    Just being curious. I was wondering what kind of material you could use to reflect a cosmic ray like visible light to a mirror. It would probably pass right through it, but I was just wondering. =P
  25. TumblingDice

    Measuring Cosmic Rays: There's an App for that

    A group of researchers from the University of California has published a paper regarding the viability of detecting cosmic rays using an array of 'SmartPhones'. I've read before that the digital sensors (photomultipliers?) in most cameras and cell phones detect infrared and, by design, this is...
  26. A

    Muons result from cosmic rays, but cosmic rays are protons that decay?

    I am wondering how Muons are manufactured. Wikipedia says they're the decay products of cosmic rays, and that cosmic rays are usually high energy protons. So a high energy proton (cosmic ray) decays into a muon after colliding with matter on earth. How is consistent with the fact that...
  27. J

    Cosmic rays affecting the LHC

    I've heard of cosmic rays affecting measurements made at the LHC in the context of muons. Is it just muons that can reach the detectors or is there background from other particles as well? Why are muons a background but not electrons? How significant is it? Thanks.
  28. marcus

    Beyond LHC without a machine (new physics from cosmic rays)

    Bee Hossenfelder has an interesting post I'd like to get some comment on http://backreaction.blogspot.com/2013/07/more-mysteries-in-cosmic-rays-and.html More mysteries in cosmic rays, and a proposed solution "...One mystery we already discussed previously. The “penetration depth” of the...
  29. A

    Cosmic Rays impact spaceship

    Hi all, I think this question goes best in this section, because I think the answer is something a nuclear or particle scientist could answer. In space, what would happen to a ship that did not have proper shielding from cosmic rays? (NOT the astronauts themselves; there is plenty of...
  30. S

    Cosmic Rays and Larmor Radius

    Homework Statement Calculate the minimum energy of a cosmic ray that it needs to have in order to "point" back to its origin. Let's define this as being deflected by the Galactic magnetic field of B = 1μG by less than 1°, as it traverses a distance of d = 1 kpc within the Galaxy. Calculate...
  31. D

    High Energy Cosmic Rays and the Origin of Life

    The advocators of Darwin’s theory of evolution discover that it is difficult for normal evolution rate alone to form the species diversity now. What factor(s) accelerated the origin of life and species diversity? Reference viewpoints: Novae, especially supernovae, would generate high energy...
  32. R

    Cosmic rays and induced radioactivity

    Homework Statement 90% of the cosmic rays that fall on Earth are protons. So the outside of the Earth is hit by a net positive charge but does not seem to be, in particular, positively charged. How do you explain this? One last thing: I read that a body that is exposed to radiation becomes...
  33. G

    Finding the Right Textbook on Cosmic Rays Hitting Earth

    I am looking for a textbook that gives a good description of the cosmic rays hitting the Earth. Do you have any suggestion? Thanks.
  34. jal

    LHCf and high-energy cosmic rays

    I don’t have any more news. Do you? http://cdsweb.cern.ch/journal/CERNBulletin/2011/17/News%20Articles/1345733?ln=en It took physicists by surprise when analysis of the data collected by the two LHCf calorimeters in 2010 showed that high-energy cosmic rays don't interact with the...
  35. M

    Density LHC vs Cosmic Rays

    Hello, I was reading the quote below in a safety debate and I had a question. It is generally accepted that flux density is not a safety issue, why is that? One would think that the more energy one fits into one place at a certain time, the more energetic the situation is. Like when you use a...
  36. M

    Can Cosmic Rays Penetrate Stones, Mountains, and the Human Body? Answers here!

    Guys please help me with an answer to this question. Which substances can cosmic rays penetrate? I mean, can the cosmic rays penetrate stones, mountains, etc etc. Can they penetrate the human body also? If yes then the cosmic rays are bound to have influence on human bodies and minds? Kindly...
  37. L

    Origin of Cosmic Rays: Intensity Explained

    we all know the cosmic rays comes from outer surface of the Earth from higher altitudes and enter the Earth's atmosphere in all directions. but experimental studies have revealed that intensity of cosmic rays increases with altitude and reaches a maximum at about 20 km above Earth surface and...
  38. I

    Cosmic rays and their detection

    Greetings, currently I'm working with cosmic rays (merely researching, not so much as working) and now I have a question regarding cosmic rays and cosmic rays detectors (specifically, Cherenkov detectors). How is the number of photons detected by the PMT's (photomultiplier tubes) related to...
  39. D

    Cosmic Rays a problem for PC reliability in near future?

    Is it to become a major problem as transitors get smaller & RAM amount goes up? A blog on NS said "This problem is projected to become a major limiter of computer reliability in the next decade." Will it be like moore's law with transistors size being a limitation? My comp has 4GB RAM &...
  40. R

    Cosmic rays - minimum ionizing particles ?

    Hello all, i am having a few problems simulating cosmic rays with a silicon CCD detector, mainly because my knowledge on particle physics is quite poor. I am simulating primary cosmic rays, which predominantly consist of single protons and alpha particles. I am treating the protons...
  41. N

    Are any Cosmic Rays antimatter

    In Kip Thorne's BLACK HOLES AND TIME WARPS,1993, he mentioned on page 173 that some cosmic rays particles are made of antimatter..and this was discovered by Carl Anderson at Caltech...seems like in the early 1930's... I could not find anything about antimatter Cosmic Rays in Wikipedia...
  42. D

    LHC vs Cosmic Rays: What's the Difference?

    Short question. I know that COLLIDING beams are much more effective than when moving particle hits a target in observers reference frame. That is why they make a collider. However, when Oh My God particles are observed they actually hit something that something does not move. So, when...
  43. fluidistic

    A question about energetic protons (cosmic rays)

    I've read that some protons in the Universe can have an energy of about 10^{20}eV, or in English, about a well-hit tennis ball. (The cosmic rays). Is it possible for these rays to reach our brain? Or more precisely, what would happen if one gets hit by such an energetic particle? P.S.: I...
  44. G

    Cosmic Rays passing through a magnetic field

    Assume that it hits the Galactic magnetic field at an angle of 45o, i.e. such that the components of its momentum parallel and perpendicular to the magnetic field are equal. What is its cyclotron radius? How long does it take to execute one cyclotron orbit? W ealso, know velocity From part...
  45. H

    Do cosmic rays have any role in our weather?

    Dose the cosmic rays have any roll in our weather This question hits me yesterday when I was studying the electric charge and its roll in the weather , so dose the cosmic rays have any roll or its roll is just negligible…. when they hit our atmosphere
  46. H

    Galactic cosmic rays and our world.

    Recently on nasa's site: http://science.nasa.gov/headlines/y2008/19nov_cosmicrays.htm [Broken] My question is...has there been any studies since 2004 to show the link between galactic cosmic rays, and cloud formation, and/or changes in cloud forming bacteria and/or the effect these have...
  47. S

    Lorentz force and cosmic rays

    I am trying to calculate the strength of the magnetic field ( in teslas ) that would be needed to deflect cosmic rays going about 99% the speed of light. using the lorents force http://en.wikipedia.org/wiki/Lorentz_force I replaced force with mass times acceleration I canceled...
  48. wolram

    Cosmic rays from solar system

    http://www.sciencedaily.com/releases/2002/10/021031071017.htm ScienceDaily (Oct. 31, 2002) — WASHINGTON - Researchers have found that a portion of anomalous cosmic rays -- charged particles accelerated to enormous energies by the solar wind -- results from interactions with dust grains from a...
  49. G

    What nuclear reactions are attributed to cosmic rays?

    http://en.wikipedia.org/wiki/Cosmic_ray I have a little bit of trouble writing an essay that relies on background knowledge of galactic cosmic rays. I found in textbooks solid writing about the history of discovery and composition, etc. I can not find simple exemplary nuclear reactions...
  50. wolram

    Can cosmic rays affect Earth's climate?