can some one tell me about the contene and details of cosmic rays?

Answer 1

Cosmic rays are radiation consisting of energetic particles originating beyond the Earth that impinge on the Earth's atmosphere. Cosmic rays are composed mainly of bare nuclei, (87% protons, 12% alpha particles = helium nuclei) and some of heavier atomic nuclei. Cosmic rays also contain electrons, gamma rays, and very high-energy neutrinos in a smaller fraction. The wide variety of particle reflects the wide variety of sources. Cosmic rays originate from energetic processes on the Sun. Cosmic rays can have energies up to 10^20 eV.
Cosmic rays were discovered in 1912, by Victor Hess. He measured the rate of ion production to an altitude of 5300 meters. He found the ionization rate increased over the rate at ground level. He concluded that a radiation of very great penetrating power enters the Earth's atmosphere from above. Hess received the Nobel Prize in Physics in 1936 for his discovery.

Answer 2

In astrophysics, cosmic rays are radiation consisting of energetic particles originating beyond the Earth that impinge on the Earth's atmosphere. Cosmic rays are composed mainly of bare nuclei, roughly 87% protons, 12% alpha particles (helium nuclei) and most of the rest being made up of heavier atomic nuclei. Electrons, gamma rays, and very high-energy neutrinos also make up a much smaller fraction of the cosmic radiation.

The kinetic energies of cosmic ray particles span over fourteen orders of magnitude, with the flux of cosmic rays on the Earth's surface falling approximately as the inverse-cube of the energy. The wide variety of particle energies reflects the wide variety of sources. Cosmic rays originate from energetic processes on the Sun all the way to the farthest reaches of the visible universe. Cosmic rays can have energies up to 1020 eV (see Oh-My-God particle for the first recorded event of a particle of such high energy). There has been interest in investigating cosmic rays of even greater energies.

Answer 3

Amazing how close those two answers are. At least the second had the decency to cite a source!

The basics are all there. They are essentially EXTREMELY HIGH ENERGY atomic nuclei (I have never heard of neutrinos referred to as cosmic rays). These things are moving a very small fraction less than the speed of light. When single atoms have energies of 10^20 eV (that is 16 Joules! Enough to lift a one kg weight 1.5 meters into the air at sea level) they are moving pretty darn fast.

These puppies are largely confined to the disk of the galaxy by the galactic magnetic field ( The really high energy ones are not), but their paths end up so perturbed by these fields, we don't have a good sense of their origin. So, people look at energy distributions and try to hypothesize.


Now, the sun IS a source of rather low energy cosmic rays, and the flux (and energies of these) can increase dramatically in concurrence with coronal mass ejections. These events are believed to be driven by magnetic reconnection events (essentially, magnetic fields get twisted up like a spring and become very strong and dense. Eventually they release rather suddenly and charged particles confined by them at that moment receive a big kick of kinetic energy).

Higher energy ones are probably produced by similar abrupt releases of energy, perhaps even magnetic energy, during large energetic events such as a supernova or a great deal of mass being dumped onto a neutron star all at once.

Cosmic rays play an important role in star formation! They enable magnetic fields to couple with cold dense clouds (aka molecular clouds) impeding their collapse. Magnetic fields only couple with charged particles. Cold places shielded from UV light (the middle of a dark dust cloud, for instance) tend to lose their charged particles as electrons recombine with ions. Cosmic rays, serve to interact with enough atoms in these cold clouds (in other words, knock the crap out of them peeling off one or more electrons) that the ion density is high enough to effectively couple magnetic fields to these largely neutral clouds. (Collisions between the neutrals and the magnetically confined charged particles are frequent enough to slow collapse.)

The process of neutral gas with a few charged particles moving across magnetic potential gradients is called "ambipolar diffusion."

Cosmic ray spellation (knocking the crap out of atomic nuclei and banging pieces off) is credited with production of essentially all of the Helium 3 (a stable isotope of helium with 2 protons and one neutron; most helium has two neutrons) in the Universe. Cosmological nucleosynthesis tended to turn He3 into regular He4 VERY efficiently.

I am sure there is a lot more out there. There has got to be a review paper on cosmic rays in "Annual Reviews in Astronomy and Astrophysics" every 5-10 years.