Loading...
  • rays
  • This explains their higher abundance in cosmic rays as compared with their ratios and abundances of certain other nuclides on Earth. (wikipedia.org)
  • These same nuclides still arrive on Earth in small amounts in cosmic rays, and are formed in meteoroids, in the atmosphere, on Earth, "cosmogenically. (wikipedia.org)
  • Most cosmogenic nuclides are formed in the atmosphere, but some are formed in situ in soil and rock exposed to cosmic rays, notably calcium-41 in the table below. (wikipedia.org)
  • It refers to the formation of chemical elements from the impact of cosmic rays on an object. (wikipedia.org)
  • Cosmic rays are highly energetic charged particles from beyond Earth, ranging from protons, alpha particles, and nuclei of many heavier elements. (wikipedia.org)
  • About 1% of cosmic rays also consist of free electrons. (wikipedia.org)
  • Cosmic rays cause spallation when a ray particle (e.g. a proton) impacts with matter, including other cosmic rays. (wikipedia.org)
  • This process goes on not only in deep space, but in Earth's upper atmosphere and crustal surface (typically the upper ten meters) due to the ongoing impact of cosmic rays. (wikipedia.org)
  • Earth is constantly bombarded with primary cosmic rays, high energy charged particles - mostly protons and alpha particles. (wikipedia.org)
  • Accordingly, by measuring the concentration of these cosmogenic nuclides in a rock sample, and accounting for the flux of the cosmic rays and the half-life of the nuclide, it is possible to estimate how long the sample has been exposed to the cosmic rays. (wikipedia.org)
  • The cumulative flux of cosmic rays at a particular location can be affected by several factors, including elevation, geomagnetic latitude, the varying intensity of the Earth's magnetic field, solar winds, and atmospheric shielding due to air pressure variations. (wikipedia.org)
  • These nuclides are particularly useful to geologists because they are produced when cosmic rays strike oxygen-16 and silicon-28, respectively. (wikipedia.org)
  • Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis. (wikipedia.org)
  • This decay, called spontaneous fission, happens when a large unstable nucleus spontaneously splits into two (or occasionally three) smaller daughter nuclei, and generally leads to the emission of gamma rays, neutrons, or other particles from those products. (wikipedia.org)
  • Another 50 or so shorter-lived radionuclides, such as radium and radon, found on Earth, are the products of decay chains that began with the primordial nuclides, or are the product of ongoing cosmogenic processes, such as the production of carbon-14 from nitrogen-14 in the atmosphere by cosmic rays. (wikipedia.org)
  • After the breakup of the meteorite parent body, it will be bombarded by cosmic rays, which will saturate it in aluminium-26. (wikipedia.org)
  • a neutron monitor can only directly detect neutrons , but is used to indirectly detect cosmic rays , high-energy charged subatomic particles impacting the Earth's atmosphere from outer space ? (thefullwiki.org)
  • Particulate Energy is given many names depending upon it energy levels: X-Rays, Gamma Rays and several flavours of Cosmic Rays. (wordpress.com)
  • Of primary cosmic rays , which originate outside of Earth's atmosphere, about 99% are the nuclei (stripped of their electron shells) of well-known atoms, and about 1% are solitary electrons (similar to beta particles). (wordpress.com)
  • Nuclear spallation occurs naturally in Earth's atmosphere owing to the impacts of cosmic rays , and also on the surfaces of bodies in space such as meteorites and the Moon. (wordpress.com)
  • Cosmic rays are very high energy particles , mainly originating in outer space , outside the Solar system . (blogspot.com)
  • The term ray is an historical accident as cosmic rays were at first, and wrongly, thought to be mostly electromagnetic radiation . (blogspot.com)
  • Now, the common usage is to call particles with non-zero rest mass "cosmic" rays, and particles ( photons ) which are quanta of electromagnetic radiation (and thus with zero rest-mass) by their common names of gamma rays or x-rays . (blogspot.com)
  • The remnants of the explosions, expanding clouds of gas and magnetic field, can last for thousands of years, and this is where cosmic rays are accelerated. (blogspot.com)
  • Bouncing back and forth in the magnetic field of the remnant randomly lets some of the particles gain energy, and become cosmic rays. (blogspot.com)
  • Because the cosmic rays eventually escape the supernova remnant, they can only be accelerated up to a certain maximum energy, which depends upon the size of the acceleration region and the magnetic field strength . (blogspot.com)
  • However, cosmic rays have been observed at much higher energies than supernova remnants can generate, and where these ultra-high energies come from is a big question. (blogspot.com)
  • There is evidence that very high energy cosmic rays are produced over far longer periods than the explosion of a single star or sudden galactic event, suggesting multiple accelerating processes occurring over very long distances as compared to the size of stars. (blogspot.com)
  • The obscure mechanisms of cosmic ray production at galactic distances is partly a result of the fact that the magnetic fields of our Solar system, our Galaxy and all other galaxies bend the path of cosmic rays, so that after a long journey through space, they arrive nearly randomly, i. e. from all directions, lacking information about the direction of their initial sources. (blogspot.com)
  • Thus, alpha particles may be loosely used as a term when referring to stellar helium nuclei reactions (for example the alpha processes), and even when they occur as components of cosmic rays. (wikipedia.org)
  • As noted, the helium nuclei that form 10-12% of cosmic rays are also usually of much higher energy than those produced by nuclear decay processes, and are thus capable of being highly penetrating and able to traverse the human body and also many meters of dense solid shielding, depending on their energy. (wikipedia.org)
  • A High-Energy Antimatter Telescope (HEAT) has been developed and tested in the mid 1990s to measure the positron fraction in cosmic rays. (wikiversity.org)
  • these elements in the cosmic rays were evidently formed from spallation of oxygen, nitrogen, carbon and perhaps silicon in the cosmic ray sources or during their lengthy travel here. (omicsgroup.org)
  • naturally
  • The additional radioactivity in the biosphere caused by human activity due to the releases of man-made radioactivity and of Naturally Occurring Radioactive Materials (NORM) can be divided into several classes. (wikipedia.org)
  • Releases of naturally occurring radioactive materials (NORM) as a result of mining etc. (wikipedia.org)
  • Since the cosmic ray spallation route is the only possible source[citation needed] of beryllium-7 and beryllium-10 occurrence naturally in the environment, they are therefore cosmogenic. (wikipedia.org)
  • A few others are naturally produced by nucleogenic processes (natural nuclear reactions of other types, such as neutron absorption). (wikipedia.org)
  • There are 29 naturally occurring chemical elements on Earth that are radioactive. (wikipedia.org)
  • In considering the known melting of small planetary bodies in the early Solar System, H. C. Urey noted that the naturally occurring long-lived radioactive nuclei (40K, 238U, 235U & 232Th) were insufficient heat sources. (wikipedia.org)
  • carbon-14
  • Also on Earth, natural transmutations from the different mechanisms of natural nuclear reactions occur, due to cosmic ray bombardment of elements (for example, to form carbon-14), and also occasionally from natural neutron bombardment (for example, see natural nuclear fission reactor). (wikipedia.org)
  • radionuclides
  • Also, the term "nucleogenic" by convention excludes artificially produced radionuclides, for example tritium, many of which are produced in large amounts by a similar artificial processes, but using the copious neutron flux produced by conventional nuclear reactors. (wikipedia.org)
  • Because there are two radionuclides decaying, the ratio of concentrations of these two nuclides can be used without any other knowledge to determine an age at which the sample was buried past the production depth (typically 2-10 meters). (wikipedia.org)
  • Such nuclides are formed in supernovas, but are known as extinct radionuclides, since they are not seen directly on the Earth today. (wikipedia.org)
  • radioactivity
  • Environmental radioactivity is produced by radioactive materials in the human environment. (wikipedia.org)
  • With his focus on radioactive supernova gas Clayton discovered a new chemical pathway causing carbon dust to condense there by a process that is activated by the radioactivity. (wikipedia.org)
  • beta decay
  • Beta-Decay A. Introduction B. Examples of -processes C. Energy diagrams D. Theory of -decay E. Rate of Decay F. Shape of Energy and Momentum Spectra G. Experimental Verification H. Selection Rules J. F Tables K. Remarks on K-capture L. Remarks on the Neutrino Hypothesis M. Neutrinos and Anti-neutrinos Chapter 5. (textbookx.com)
  • short-lived
  • He proposed that the heat sources from short lived nuclei from newly formed stars might be the source and identified 26Al as the most likely choice. (wikipedia.org)
  • interacts
  • The energy of an excited nucleus may be emitted as a gamma ray in a process called gamma decay, or that energy may be lost when the nucleus interacts with an orbital electron causing its ejection from the atom, in a process called internal conversion. (wikipedia.org)
  • atmosphere
  • Helium's other industrial uses-as a pressurizing and purge gas, as a protective atmosphere for arc welding and in processes such as growing crystals to make silicon wafers -account for half of the gas produced. (wikipedia.org)