What are cosmic rays?
Cosmic rays are tiny particles, mostly protons, that slam into the Earth’s atmosphere at various levels of energy. Billions of cosmic rays are slamming into the Earth every second, most of them with a quite low energy. However, every once in a while cosmic rays with extreme levels of energy impact the Earth. The most powerful yet recorded was a single proton with an energy of 50 J, roughly equivalent to a baseball pitch. Scientists are at a loss to explain how some of the most energetic rays got their energy. Although they are called “cosmic rays,” it should be noted that cosmic rays are point-like particles, not rays. Aside from protons, which make up 90% of all cosmic rays, there are also helium nuclei, also known as alpha particles, which make up another 9%, and electrons which make up the remaining 1%. Outer space is filled with a bath of fast-moving particles, known as the cosmic ray flux. Cosmic rays are called ionizing radiation because they have the tendency to impact molecules
Galactic cosmic rays (GCRs) are the high-energy particles that flow into our solar system from far away in the Galaxy. GCRs are mostly pieces of atoms: protons, electrons, and atomic nuclei which have had all of the surrounding electrons stripped during their high-speed (almost the speed of light) passage through the Galaxy. Cosmic rays provide one of our few direct samples of matter from outside the solar system. The magnetic fields of the Galaxy, the solar system, and the Earth have scrambled the flight paths of these particles so much that we can no longer point back to their sources in the Galaxy. If you made a map of the sky with cosmic ray intensities, it would be completely uniform. So we have to determine where cosmic rays come from by indirect means.
Can you give me a good explanation of what a cosmic ray is? I think that the description given on our cosmic ray page and the pages linked from it are what you want. If you’ve got a more specific question, feel free to send more email. Dr. Eric Christian • Why Do We Study Cosmic Rays? Why is the study of cosmic rays important? What do scientists hope to achieve by studying cosmic rays? Why should the average person be interested in the study of cosmic rays? These are excellent questions and all interrelated. Cosmic rays are to scientists much like photons are to astronomers. Just as astronomers use light (or photons) to view our Galaxy and beyond, scientists use cosmic rays to infer useful properties about our Galaxy, such as its composition, its basic structure (is the Galaxy homogeneous? is there an extended halo surrounding our Galaxy?), and what common physical processes occur within the Galaxy (how nuclei accelerate to nearly the speed of light, what kinds of nuclear collisions ta
Cosmic rays are nuclear particles that originate from outer space. Some originate from the sun, whereas the remainder come from further a field. Cosmic rays are mainly high energy protons, and when they reach of the top of the atmosphere they interact with the materials and gases there, in the process producing additional nuclear particles. Some of these particles pass through the atmosphere and reach the ground surface. The atmosphere attenuates cosmic rays so that their intensity at ground level is not as high as it is in the upper atmosphere. Interestingly, frequent flyers, such as pilots, need to have their radiation dose due to cosmic rays monitored.
