Cosmic rays are energetic particles originating from space that impinge on Earth's atmosphere. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Almost 90% of all the incoming cosmic ray particles are protons, about 9% are helium nuclei (alpha particles) and about 1% are electrons (beta minus particles). The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Beta particles are high-energy high-speed Electrons or Positrons emitted by certain types of Radioactive nuclei such as Potassium -40 The term "ray" is a misnomer, as cosmic particles arrive individually, not in the form of a ray or beam of particles.

The variety of particle energies reflects the wide variety of sources. The origins of these particles range from energetic processes on the Sun all the way to as yet unknown events in the farthest reaches of the visible universe. The Sun (Sol is the Star at the center of the Solar System. The Universe is defined as everything that Physically Exists: the entirety of Space and Time, all forms of Matter, Energy Cosmic rays can have energies of over 10²⁰ eV, far higher than the 10¹² to 10¹³ eV that man-made particle accelerators can produce. (See Ultra-high-energy cosmic rays for a description of the detection of a single particle with an energy of about 50 J, the same as a well-hit tennis ball at 42 m/s [about 94 mph]. In high-energy physics, an ultra-high-energy cosmic ray ( UHECR) or extreme-energy cosmic ray ( EECR) is a Cosmic ray (subatomic particle ) There has been interest in investigating cosmic rays of even greater energies. ^[1]

Contents 1 Cosmic ray sources 1.1 Solar cosmic rays 1.2 Galactic cosmic rays 1.3 Extragalactic cosmic rays 1.4 Ultra-high-energy cosmic rays 1.5 Anomalous cosmic rays 2 Composition 3 Modulation 4 Detection 4.1 Detection by particle track-etch technique 4.2 Interaction with the Earth's atmosphere 5 Unusual cosmic rays 6 Research and experiments 7 History 8 Effects 8.1 Role in ambient radiation 8.2 Effect on electronics 8.3 Significance to space travel 8.4 Role in lightning 8.5 Role in climate change 9 Cosmic rays and fiction 10 See also 11 Notes 12 References 13 External links

Cosmic ray sources

Most cosmic rays originate from extrasolar sources within our own galaxy such as rotating neutron stars, supernovae, and black holes. A neutron star is a type of remnant that can result from the Gravitational collapse of a massive Star during a Type II, Type Ib or Type A supernova (plural supernovae or supernovas) is a stellar Explosion. A black hole is a theoretical region of space in which the Gravitational field is so powerful that nothing not even Electromagnetic radiation (e However, the fact that some cosmic rays have extremely high energies provides evidence that at least some must be of extra-galactic origin (e. g. radio galaxies and quasars); the local galactic magnetic field would not be able to contain particles with such a high energy. Radio galaxies and their relatives radio-loud Quasars and Blazars, are types of Active galaxy that are very luminous at radio wavelengths (up A quasar (contraction of QUASi-stellAR radio source) is an extremely powerful and distant Active galactic nucleus. The origin of cosmic rays with energies up to 10¹⁴ eV can be accounted for in terms of shock-wave acceleration in supernova shells. The origin of cosmic rays with energy greater than 10¹⁴ eV remained unknown until recently, when a large collaborative experiment at the Pierre Auger Observatory appears to have answered this question. Pierre Auger Observatory is an international Cosmic ray observatory designed to detect ultra high energy cosmic rays -- Ultra-high-energy particles These are sub-atomic In preliminary results announced in November 2007, they showed a strong correlation between their 27 most energetic events and active galactic nuclei [AGN]. An active galactic nucleus ( AGN) is a compact region at the centre of a Galaxy which has a much higher than normal luminosity over some or all of the Electromagnetic These results demonstrated that there is only a small chance (less than 1/100) that the highest energy protons originated from outside the AGN.

Observations have shown that cosmic rays with an energy above 10 GeV (10 x 10⁹ eV) approach the Earth’s surface isotropically (equally from all directions); it has been hypothesized that this is not due to an even distribution of cosmic ray sources, but instead is due to galactic magnetic fields causing cosmic rays to travel in spiral paths. This limits cosmic ray’s usefulness in positional astronomy as they carry no information of their direction of origin. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study At energies below 10 GeV there is a directional dependence, due to the interaction of the charged component of the cosmic rays with the Earth's magnetic field. Earth 's magnetic field (and the surface magnetic field) is approximately a Magnetic dipole, with one pole near the North pole (see

Solar cosmic rays

Solar cosmic rays or solar energetic particles (SEP) are cosmic rays that originate from the Sun. Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s The Sun (Sol is the Star at the center of the Solar System. The average composition is similar to that of the Sun itself. There exists no clear and sharp boundary between the phase spaces of the solar wind and SEP plasma particle populations. The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. ^[2]

The name solar cosmic ray itself is a misnomer because the term cosmic implies that the rays are from the cosmos and not the solar system, but it has stuck. The misnomer arose because there is continuity in the energy spectra, i. e. , the flux of particles as a function of their energy, because the low-energy solar cosmic rays fade more or less smoothly into the galactic ones as one looks at increasingly higher energies. Until the mid-1960s the energy distributions were generally averaged over long time intervals, which also obscured the difference. Later, it was found that the solar cosmic rays vary widely in their intensity and spectrum, increasing in strength after some solar events such as solar flares. Further, an increase in the intensity of solar cosmic rays is followed by a decrease in all other cosmic rays, called the Forbush decrease after their discoverer, the physicist Scott Forbush. A Forbush decrease is a rapid decrease in the observed Galactic cosmic ray intensity following a Coronal mass ejection (CME These decreases are due to the solar wind with its entrained magnetic field sweeping some of the galactic cosmic rays outwards, away from the Sun and Earth. The overall or average rate of Forbush decreases tends to follow the 11-year sunspot cycle, but individual events are tied to events on the Sun, as explained above.

There are further differences between cosmic rays of solar and galactic origin, mainly in that the galactic cosmic rays show an enhancement of heavy elements such as calcium, iron and gallium, as well as of cosmically rare light elements such as lithium and beryllium. Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Gallium (ˈgæliəm is a Chemical element that has the symbol Ga and Atomic number 31 Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Beryllium (bəˈrɪliəm is a Chemical element with the symbol Be and Atomic number 4 The latter result from the cosmic ray spallation (fragmentation) of heavy nuclei due to collisions in transit from the distant sources to the solar system. Cosmic ray spallation is a form of naturally occurring Nuclear fission and Nucleosynthesis.

Galactic cosmic rays

See Galactic cosmic ray. Galactic cosmic rays ( GCRs) consist of those Cosmic rays that enter the solar system from the outside

Extragalactic cosmic rays

See Extragalactic cosmic ray. Extragalactic cosmic rays are very-high-energy particles that flow into our solar system from beyond our galaxy.

Ultra-high-energy cosmic rays

See Ultra-high-energy cosmic ray. In high-energy physics, an ultra-high-energy cosmic ray ( UHECR) or extreme-energy cosmic ray ( EECR) is a Cosmic ray (subatomic particle

Anomalous cosmic rays

Anomalous cosmic rays (ACRs) are cosmic rays with unexpectedly low energies. They are thought to be created near the edge of our solar system, in the heliosheath, the border region between the heliosphere and the interstellar medium. The heliosphere is a bubble in space "blown" into the Interstellar medium (the hydrogen and helium gas that permeates the Galaxy) by the The heliosphere is a bubble in space "blown" into the Interstellar medium (the hydrogen and helium gas that permeates the Galaxy) by the When electrically neutral atoms are able to enter the heliosheath (being unaffected by its magnetic fields) subsequently become ionized, they are thought to be accelerated into low-energy cosmic rays by the solar wind's termination shock which marks the inner edge of the heliosheath. The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. The heliosphere is a bubble in space "blown" into the Interstellar medium (the hydrogen and helium gas that permeates the Galaxy) by the It is also possible that high energy galactic cosmic rays which hit the shock front of the solar wind near the heliopause might be decelerated, resulting in their transformation into lower-energy anomalous cosmic rays. Galactic cosmic rays ( GCRs) consist of those Cosmic rays that enter the solar system from the outside A bow shock is a boundary between a Magnetosphere and an ambient medium The heliosphere is a bubble in space "blown" into the Interstellar medium (the hydrogen and helium gas that permeates the Galaxy) by the

The Voyager 1 space probe crossed the termination shock on December 16, 2004, according to papers published in the journal Science. The Voyager 1 spacecraft is a 722-kilogram robotic Space probe of the outer Solar system and beyond launched September 5, Events 755 - An Lushan revolts against Chancellor Yang Guozhong at Fanyang, initiating the An Shi Rebellion "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " ^[3] Readings showed particle acceleration, but not of the kind that generates ACRs. It is unclear at this stage (September 2005) if this is typical of the termination shock (requiring a major rethink of the origin of ACRs), or a localised feature of that part of the termination shock that Voyager 1 passed through. PortalCurrent events News collections and sources WikipediaNews collections and sources. Voyager 2 is expected to cross the termination shock during or after 2008, which will provide more data. Voyager 2 is an unmanned Interplanetary Spacecraft launched on August 20, 1977. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common

Composition

Cosmic rays may broadly be divided into two categories, primary and secondary. The cosmic rays that arise in extrasolar astrophysical sources are primary cosmic rays; these primary cosmic rays can interact with interstellar matter to create secondary cosmic rays. The sun also emits low energy cosmic rays associated with solar flares. A solar flare is a violent explosion in a star's (like the Sun 's atmosphere releasing as much Energy as 6 × 1025 Joules Solar flares The exact composition of primary cosmic rays, outside the Earth's atmosphere, is dependent on which part of the energy spectrum is observed. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five An energy spectrum is a distribution of Energy among a large assemblage of particles However, in general, almost 90% of all the incoming cosmic rays are protons, about 9% are helium nuclei (alpha particles) and about 1% are electrons. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The remaining fraction is made up of the other heavier nuclei which are abundant end products of star’s nuclear synthesis. Secondary cosmic rays consist of the other nuclei which are not abundant nuclear synthesis end products, or products of the Big Bang, primarily lithium, beryllium and boron. The Big Bang is the cosmological model of the Universe that is best supported by all lines of scientific evidence and Observation. Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Beryllium (bəˈrɪliəm is a Chemical element with the symbol Be and Atomic number 4 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. These light nuclei appear in cosmic rays in much greater abundance (about 1:100 particles) than in solar atmospheres, where their abundance is about 10^-7 that of helium. Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical

This abundance difference is a result of the way secondary cosmic rays are formed. When the heavy nuclei components of primary cosmic rays, namely the carbon and oxygen nuclei, collide with interstellar matter, they break up into lighter nuclei (in a process termed cosmic ray spallation), into lithium, beryllium and boron. Cosmic ray spallation is a form of naturally occurring Nuclear fission and Nucleosynthesis. It is found that the energy spectra of Li, Be and B falls off somewhat steeper than that of carbon or oxygen, indicating that less cosmic ray spallation occurs for the higher energy nuclei presumably due to their escape from the galactic magnetic field. Cosmic ray spallation is a form of naturally occurring Nuclear fission and Nucleosynthesis. Spallation is also responsible for the abundances of Sc, Ti, V and Mn elements in cosmic rays, which are produced by collisions of Fe and Ni nuclei with interstellar matter; see Environmental radioactivity#Naturals. Environmental Radioactivity is the study of radioactive materials in the Human environment.

In the past, it was believed that the cosmic ray flux has remained fairly constant over time. In the various subfields of Physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks Recent research has, however, produced evidence for 1. 5 to 2-fold millennium-timescale changes in the cosmic ray flux in the past forty thousand years. ^[4]

Modulation

The flux (flow rate) of cosmic rays incident on the Earth’s upper atmosphere is modulated (varied) by two processes; the sun’s solar wind and the Earth's magnetic field. In the various subfields of Physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. Earth 's magnetic field (and the surface magnetic field) is approximately a Magnetic dipole, with one pole near the North pole (see Solar wind is expanding magnetized plasma generated by the sun, which has the effect of decelerating the incoming particles as well as partially excluding some of the particles with energies below about 1 GeV. The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound The amount of solar wind is not constant due to changes in solar activity over its regular eleven-year cycle. The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. Hence the level of modulation varies in autocorrelation with solar activity. Also the Earth's magnetic field deflects some of the cosmic rays, which is confirmed by the fact that the intensity of cosmic radiation is dependent on latitude, longitude and azimuth. Earth 's magnetic field (and the surface magnetic field) is approximately a Magnetic dipole, with one pole near the North pole (see Latitude, usually denoted symbolically by the Greek letter phi ( Φ) gives the location of a place on Earth (or other planetary body north or south of the Longitude (ˈlɒndʒɪˌtjuːd or ˈlɒŋgɪˌtjuːd symbolized by the Greek character Lambda (λ is the east-west Geographic coordinate measurement Azimuth ( is a mathematical concept defined as the angle usually measured in degrees (° between a reference plane and a point. The cosmic flux varies from eastern and western directions due to the polarity of the Earth’s geomagnetic field and the positive charge dominance in primary cosmic rays; this is termed the east-west effect. "Polar molecule" and "Non-polar" redirect here The cosmic ray intensity at the equator is lower than at the poles as the geomagnetic cutoff value is greatest at the equator. This can be understood by the fact that charged particle tend to move in the direction of field lines and not across them. This is the reason the Aurorae occur at the poles, since the field lines curve down towards the Earth’s surface there. Finally, the longitude dependence arises from the fact that the geomagnetic dipole axis is not parallel to the Earth’s rotation axis. Longitude (ˈlɒndʒɪˌtjuːd or ˈlɒŋgɪˌtjuːd symbolized by the Greek character Lambda (λ is the east-west Geographic coordinate measurement In physics there are two kinds of dipoles ( Hellènic: di(s- = two- and pòla = pivot hinge An electric dipole is a

This modulation which describes the change in the interstellar intensities of cosmic rays as they propagate in the heliosphere is highly energy and spatial dependent, and it is described by the Parker's Transport Equation in the heliosphere. The heliosphere is a bubble in space "blown" into the Interstellar medium (the hydrogen and helium gas that permeates the Galaxy) by the At large radial distances, far from the Sun ~ 94 AU, there exists the region where the solar wind undergoes a transition from supersonic to subsonic speeds called the solar wind termination shock. The astronomical unit ( AU or au or au or sometimes ua) is a unit of Length based on the distance from the Earth to the The region between the termination shock and the heliospause (the boundary marking the end of the heliosphere) is called the heliosheath. The heliosphere is a bubble in space "blown" into the Interstellar medium (the hydrogen and helium gas that permeates the Galaxy) by the This region acts as a barrier to cosmic rays and it decreases their intensities at lower energies by about 90% indicating that it is not only the Earth's magnetic field that protect us from cosmic ray bombardment. In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges For more on this topic and how the barrier effects occur the agile reader is referred to Mabedle Donald Ngobeni and Marius Potgieter (2007), and Mabedle Donald Ngobeni (2006).

From modelling point of view, there is a challenge in determining the Local Interstellar spectra (LIS) due to large adiabatic energy changes these particles experience owing to the diverging solar wind in the heliosphere. Scientific modelling is the process of generating abstract, conceptual, Graphical and or mathematical models. A spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. However, significant progress has been made in the field of cosmic ray studies with the development of an improved state-of-the-art 2D numerical model that includes the simulation of the solar wind termination shock, drifts and the heliosheath coupled with fresh descriptions of the diffusion tensor, see Langner et al. Diffusion MRI is a Magnetic resonance imaging (MRI method that produces In vivo images of biological tissues weighted with the local microstructural (2004). But challenges also exist because the structure of the solar wind and the turbulent magnetic field in the heliosheath is not well understood indicating the heliosheath as the region unknown beyond. With lack of knowledge of the diffusion coefficient perpendicular to the magnetic field our knowledge of the heliosphere and from the modelling point of view is far from complete. There exist promising theories like ab initio approaches, but the drawback is that such theories produce poor compatibility with observations (Minnie, 2006) indicating their failure in describing the mechanisms influencing the cosmic rays in the heliosphere. Ab initio quantum chemistry methods are Computational chemistry methods based on Quantum chemistry.

Detection

The nuclei that make up cosmic rays are able to travel from their distant sources to the Earth because of the low density of matter in space. Soudan 2 was a particle detector located in the Soudan Mine in Northern Minnesota United States Nuclei interact strongly with other matter, so when the cosmic rays approach Earth they begin to collide with the nuclei of atmospheric gases. These collisions, in a process known as a shower, result in the production of many pions and kaons, unstable mesons which quickly decay into muons. In Particle physics, a shower is a cascade of secondary particles produced as the result of a high- Energy particle interacting with dense matter In Particle physics, pion (short for pi meson) is the collective name for three Subatomic particles, and. In Particle physics, a kaon (/ˈkeɪɒn/ also called K-meson and denoted) is any one of a group of four Mesons distinguished by the fact that they In Particle physics, a meson is a strongly interacting Boson &mdashthat is a Hadron with integer spin. The muon (from the letter mu (μ--used to represent it is an Elementary particle with negative Electric charge and a spin of 1/2 Because muons do not interact strongly with the atmosphere and because of the relativistic effect of time dilation many of these muons are able to reach the surface of the Earth. This article discusses a concept in physics For the concept in sociology see Time displacement. Muons are ionizing radiation, and may easily be detected by many types of particle detectors such as bubble chambers or scintillation detectors. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation A bubble chamber is a vessel filled with a superheated transparent Liquid (most often Liquid hydrogen) used to detect electrically charged Scintillation is a flash of Light produced in a transparent material by an Ionization event If several muons are observed by separated detectors at the same instant it is clear that they must have been produced in the same shower event.

Detection by particle track-etch technique

Cosmic rays can also be detected directly when they pass through particle detectors flown aboard satellites or in high altitude balloons. In a pioneering technique developed by P. Buford Price et al. Dr Paul Buford Price, usually known as P Buford Price, is a Professor in the Graduate School at the University of California Berkeley and a member of , sheets of clear plastic such as 1/4 mil Lexan polycarbonate can be stacked together and exposed directly to cosmic rays in space or high altitude. For similar products offered by other companies see Polycarbonates Lexan ( LEXAN) is a registered trademark for SABIC Innovative When returned to the laboratory, the plastic sheets are "etched" [literally, slowly dissolved] in warm caustic sodium hydroxide solution, which slowly removes the surface material at a slow, known rate. Sodium hydroxide ( Na[[hydroxide OH]]) also known as Lye, caustic soda and (incorrectly according to IUPAC nomenclature Wherever a bare cosmic ray nucleus passes through the detector, the nuclear charge causes chemical bond breaking in the plastic. The slower the particle, the more extensive is the bond-breaking along the path; and the higher the charge [the higher the Z], the more extensive is the bond-breaking along the path. The caustic sodium hydroxide dissolves at a faster rate along the path of the damage, but thereafter dissolves at the slower base-rate along the surface of the minute hole that was drilled. The net result is a conical shaped pit in the plastic; typically with two pits per sheet [one originating from each side of the plastic]. The etch pits can be measured under a high power microscope [typically 1600X oil-immersion], and the etch rate plotted as a function of the depth in the stack of plastic. At the top of the stack, the ionization damage is less due to the higher speed. As the speed decreases due to deceleration in the stack, the ionization damage increases along the path. This generates a unique curve for each atomic nucleus of Z from 1 to 92, allowing identification of both the charge and energy [speed] of the particle that traverses the stack. This technique has been used with great success for detecting not only cosmic rays, but fission product nuclei for neutron detectors.

Interaction with the Earth's atmosphere

When cosmic ray particles enter the Earth's atmosphere they collide with molecules, mainly oxygen and nitrogen, to produce a cascade of lighter particles, a so-called air shower. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by An air shower is an extensive (many kilometres wide cascade of ionized particles and Electromagnetic radiation produced in the atmosphere when a primary The general idea is shown in the figure which shows a cosmic ray shower produced by a high energy proton of cosmic ray origin striking an atmospheric molecule.

This image is a simplified picture of an air shower: in reality, the number of particles created in an air shower event can reach in the billions, depending on the energy and chemical environment (i. e. atmospheric) of the primary particle. All of the produced particles stay within about one degree of the primary particle's path. Typical particles produced in such collisions are charged mesons (e. In Particle physics, a meson is a strongly interacting Boson &mdashthat is a Hadron with integer spin. g. positive and negative pions and kaons); one common collision is:

Cosmic rays are also responsible for the continuous production of a number of unstable isotopes in the Earth’s atmosphere, such as carbon-14, via the reaction:

Cosmic rays kept the level of carbon-14 in the atmosphere roughly constant (70 tons) for at least the past 100,000 years, until the beginning of aboveground nuclear weapons testing in the early 1950s. In Particle physics, pion (short for pi meson) is the collective name for three Subatomic particles, and. In Particle physics, a kaon (/ˈkeɪɒn/ also called K-meson and denoted) is any one of a group of four Mesons distinguished by the fact that they A radionuclide is an Atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created Carbon-14, 14C, or radiocarbon, is a Radioactive isotope of Carbon discovered on February 27, 1940, by Carbon-14, 14C, or radiocarbon, is a Radioactive isotope of Carbon discovered on February 27, 1940, by This is an important fact used in radiocarbon dating which is used in archaeology. Radiocarbon dating is a Radiometric dating method that uses the naturally occurring Radioisotope Carbon-14 (14C to determine the age of Archaeology, archeology, or archæology (from Greek grc ἀρχαιολογία archaiologia – grc ἀρχαῖος archaīos

Searches for such MBHs via a possible Hawking radiation emission signal might be taken at the Pierre Auger cosmic ray observatory. Hawking radiation (also known as Bekenstein-Hawking radiation) is a Thermal radiation with a black body spectrum predicted to be emitted by Black holes Pierre Victor Auger ( May 14, 1899 &ndash December 25, 1993) was a French Physicist Additionally, searches for Hawking Radiation are planned for possible MBHs that might be created at the Large Hadron Collider [LHC].

Unusual cosmic rays

In 1975, a team of researchers headed by P. Buford Price at U.C. Berkeley announced the discovery^[5] of a cosmic ray track in a particle detector slung under a high-altitude balloon that was significantly different from all others ever measured. Dr Paul Buford Price, usually known as P Buford Price, is a Professor in the Graduate School at the University of California Berkeley and a member of The University of California Berkeley (also referred to as Cal, Berkeley and UC Berkeley) is a major research university located in Berkeley Using the particle track-etch method pioneered by Price, et al. , they discovered the track of a particle that had passed through 32 sheets of 1/4 mil Lexan plastic without any measurable change in ionization. For similar products offered by other companies see Polycarbonates Lexan ( LEXAN) is a registered trademark for SABIC Innovative Yet, the Cerenkov detector admitted only of particles less than 2/3 c [the speed of light in the clear plastic]. Pavel Alekseyevich Cherenkov (Павел Алексеевич Черенков 1904-1990 was a Soviet physicist who won the Nobel Prize in physics in 1958 for The charge was measured as being 137, the same as predicted by Paul Dirac who first predicted the theoretical existence of magnetic monopoles. In Physics, a magnetic monopole is a hypothetical particle that is a Magnet with only one pole (see Maxwell's equations for more on magnetic The particle track preliminarily identified as having been caused by a magnetic monopole had been spotted by technical assistant Walter L. Wagner. ^[6]

A possible alternative explanation was offered by Alvarez^[7]. In his paper it was demonstrated that the path of the cosmic ray event that was claimed to be due to a magnetic monopole could be reproduced by a path followed by a platinum nucleus fragmenting to osmium and then to tantalum.

Research and experiments

There are a number of cosmic ray research initiatives. These include, but are not limited to:

• CHICOS
• PAMELA
• Alpha Magnetic Spectrometer
• MARIACHI
• Pierre Auger Observatory
• Spaceship Earth

History

After the discovery of radioactivity by Henri Becquerel in 1896, it was generally believed that atmospheric electricity (ionization of the air) was caused only by radiation from radioactive elements in the ground or the radioactive gases (isotopes of radon) they produce. The California High School Cosmic Ray Observatory, (abbreviated CHICOS, for C alifornia HI gh school C osmic ray O b' S' ervatory PAMELA is a Bacronym for P ayload for A ntimatter M atter E xploration and L ight-nuclei A strophysics The Alpha Magnetic Spectrometer (AMS is a particle physics experiment that is to be mounted on the International Space Station designed to search for various types of unusual MARIACHI, the Mixed Apparatus for Radar Investigation of Cosmic-rays of High Ionization, is an apparatus for the detection of Ultra-high-energy cosmic rays (UHECR Pierre Auger Observatory is an international Cosmic ray observatory designed to detect ultra high energy cosmic rays -- Ultra-high-energy particles These are sub-atomic Spaceship Earth is a network of Neutron monitors designed to measure the flux of Cosmic rays arriving at Earth from different directions Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Antoine Henri Becquerel (15 December 1852 &ndash 25 August 1908 was a French Physicist, Nobel laureate, and one of the discoverers of Radioactivity Ionization is the physical process of converting an Atom or Molecule into an Ion by adding or removing charged particles such as Electrons Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Radiation, as in Physics, is Energy in the form of waves or moving Subatomic particles emitted by an atom or other body as it changes from a higher energy Radon (ˈreɪdɒn is the Chemical element that has the symbol Rn and Atomic number 86 Measurements of ionization rates at increasing heights above the ground during the decade from 1900 to 1910 showed a decrease that could be explained as due to absorption of the ionizing radiation by the intervening air. Then, in 1912, Victor Hess carried three Wulf electrometers (a device to measure the rate of ion production inside a hermetically sealed container) to an altitude of 5300 meters in a free balloon flight. Victor Francis Hess ( June 24, 1883 &ndash December 17, 1964) was an Austrian American Physicist, and Theodor Wulf ( July 28, 1868 - June 19, 1946) was a German Physicist and Jesuit priest who was one of the first An electrometer is an electrical instrument for measuring Electric charge or electrical Potential difference. The hot air balloon is the oldest successful human-carrying Flight technology He found the ionization rate increased approximately fourfold over the rate at ground level. He concluded "The results of my observation are best explained by the assumption that a radiation of very great penetrating power enters our atmosphere from above. " In 1913-14, Werner Kolhörster confirmed Victor Hess' results by measuring the increased ionization rate at an altitude of 9 km. Werner Heinrich Gustav Kolhörster ( December 28, 1887 &ndash August 5, 1946) was a German Physicist and a pioneer of research Hess received the Nobel Prize in Physics in 1936 for his discovery of what came to be called "cosmic rays". The Nobel Prize in Physics (Nobelpriset i fysik is awarded once a year by the Royal Swedish Academy of Sciences.

For many years it was generally believed that cosmic rays were high-energy photons (gamma rays) with some secondary electrons produced by Compton scattering of the gamma rays. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The Compton shift formula Klein-Nishina formulaCompton used a combination of three fundamental formulas representing the various aspects of classical and modern physics combining Then, during the decade from 1927 to 1937 a wide variety of experimental investigations demonstrated that the primary cosmic rays are mostly positively charged particles, and the secondary radiation observed at ground level is composed primarily of a "soft component" of electrons and photons and a "hard component" of penetrating particles, muons. The muon (from the letter mu (μ--used to represent it is an Elementary particle with negative Electric charge and a spin of 1/2 The muon was initially believed to be the unstable particle predicted by Hideki Yukawa in 1935 in his theory of the nuclear force. né, was a Japanese Theoretical physicist and the first Japanese Nobel laureate. The nuclear force (or nucleon-nucleon interaction or residual strong force) is the force between two or more Nucleons It is responsible for Experiments proved that the muon decays with a mean life of 2. Given an assembly of elements the number of which decreases ultimately to zero the lifetime (also called the mean lifetime) is a certain number that characterizes the rate 2 microseconds into an electron and two neutrinos, but that it does not interact strongly with nuclei, so it could not be the Yukawa particle. Neutrinos are Elementary particles that travel close to the Speed of light, lack an Electric charge, are able to pass through ordinary matter almost In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and The nucleus of an Atom is the very dense region consisting of Nucleons ( Protons and Neutrons, at the center of an atom The mystery was solved by the discovery in 1947 of the pion, which is produced directly in high-energy nuclear interactions. In Particle physics, pion (short for pi meson) is the collective name for three Subatomic particles, and. It decays into a muon and one neutrino with a mean life of 0. 0026 microseconds. The pion→muon→electron decay sequence was observed directly in a microscopic examination of particle tracks in a special kind of photographic plate called a nuclear emulsion that had been exposed to cosmic rays at a high-altitude mountain station. In 1948, observations with nuclear emulsions carried by balloons to near the top of the atmosphere by Gottlieb and Van Allen showed that the primary cosmic particles are mostly protons with some helium nuclei (alpha particles) and a small fraction heavier nuclei. Melvin Burt Gottlieb ( May 25, 1917, in Chicago Illinois – December 1, 2000, in Haverford Township Pennsylvania) was James Alfred Van Allen ( September 7 1914 &ndash August 9, 2006) was an American space scientist at the University of Iowa The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a

In 1934 Bruno Rossi reported an observation of near-simultaneous discharges of two Geiger counters widely separated in a horizontal plane during a test of equipment he was using in a measurement of the so-called east-west effect. Bruno Benedetto Rossi ( April 13 1905 &ndash November 21 1993) was a leading Italian - American experimental physicist A Geiger counter, also called a Geiger-Müller counter, is a type of Particle detector that measures Ionizing radiation. In his report on the experiment, Rossi wrote ". . . it seems that once in a while the recording equipment is struck by very extensive showers of particles, which causes coincidences between the counters, even placed at large distances from one another. Unfortunately, he did not have the time to study this phenomenon more closely. " In 1937 Pierre Auger, unaware of Rossi's earlier report, detected the same phenomenon and investigated it in some detail. Pierre Victor Auger ( May 14, 1899 &ndash December 25, 1993) was a French Physicist He concluded that extensive particle showers are generated by high-energy primary cosmic-ray particles that interact with air nuclei high in the atmosphere, initiating a cascade of secondary interactions that ultimately yield a shower of electrons, photons, and muons that reach ground level. An air shower is an extensive (many kilometres wide cascade of ionized particles and Electromagnetic radiation produced in the atmosphere when a primary

Homi J. Bhabha derived an expression for the probability of scattering positrons by electrons, a process now known as Bhabha scattering. This page is about the physicist Homi J Bhabha For the postcolonialist theorist see Homi K His classic paper, jointly with Warren Heitler, published in 1937 described how primary cosmic rays from space interact with the upper atmosphere to produce particles observed at the ground level. Bhabha and Heitler explained the cosmic ray shower formation by the cascade production of gamma rays and positive and negative electron pairs. In 1938 Bhabha concluded that observations of the properties of such particles would lead to the straightforward experimental verification of Albert Einstein's theory of relativity.

Measurements of the energy and arrival directions of the ultra-high-energy primary cosmic rays by the techniques of "density sampling" and "fast timing" of extensive air showers were first carried out in 1954 by members of the Rossi Cosmic Ray Group at the Massachusetts Institute of Technology. The experiment employed eleven scintillation detectors arranged within a circle 460 meters in diameter on the grounds of the Agassiz Station of the Harvard College Observatory. A scintillator is a substance that absorbs high-energy (ie Ionizing) electromagnetic or charged Particle radiation then in response fluoresces The Harvard College Observatory (or HCO is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Department of Astronomy From that work, and from many other experiments carried out all over the world, the energy spectrum of the primary cosmic rays is now known to extend beyond 10²⁰ eV (past the GZK cutoff, beyond which very few cosmic rays should be observed). The Greisen-Zatsepin-Kuzmin limit ( GZK limit) is a theoretical upper limit on the energy of Cosmic rays from distant sources A huge air shower experiment called the Auger Project is currently operated at a site on the pampas of Argentina by an international consortium of physicists. Pierre Auger Observatory is an international Cosmic ray observatory designed to detect ultra high energy cosmic rays -- Ultra-high-energy particles These are sub-atomic Laguna de Gomezjpg|thumb|left|240px|Lake Gomez near Junín in the heart of the Pampas grain belt Their aim is to explore the properties and arrival directions of the very highest energy primary cosmic rays. The results are expected to have important implications for particle physics and cosmology. In November, 2007 preliminary results were announced showing direction of origination of the 27 highest energy events were strongly correlated with the locations of active galactic nuclei [AGN], where bare protons are believed accelerated by strong magnetic fields associated with the large black holes at the AGN centers to energies of 1E20 eV and higher. An active galactic nucleus ( AGN) is a compact region at the centre of a Galaxy which has a much higher than normal luminosity over some or all of the Electromagnetic A black hole is a theoretical region of space in which the Gravitational field is so powerful that nothing not even Electromagnetic radiation (e

Three varieties of neutrino are produced when the unstable particles produced in cosmic ray showers decay. Neutrinos are Elementary particles that travel close to the Speed of light, lack an Electric charge, are able to pass through ordinary matter almost Since neutrinos interact only weakly with matter most of them simply pass through the Earth and exit the other side. The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature They very occasionally interact, however, and these atmospheric neutrinos have been detected by several deep underground experiments. The Super-Kamiokande in Japan provided the first convincing evidence for neutrino oscillation in which one flavour of neutrino changes into another. Super-Kamiokande, or Super-K for short is a neutrino observatory in the city of Hida, Gifu Prefecture, Japan. Neutrino oscillation is a quantum mechanical phenomenon predicted by Bruno Pontecorvo whereby a Neutrino created with a specific Lepton In Particle physics, flavour or flavor (see spelling differences) is a Quantum number of Elementary particles related to their The evidence was found in a difference in the ratio of electron neutrinos to muon neutrinos depending on the distance they have traveled through the air and earth.

Effects

Role in ambient radiation

Cosmic rays constitute a fraction of the annual radiation exposure of human beings on earth. For example, the average radiation exposure in Australia is 0. 3 mSv due to cosmic rays, out of a total of 2. The sievert (symbol Sv is the SI derived unit of dose equivalent. 3 mSv. [1]

Effect on electronics

Cosmic rays have sufficient energy to alter the states of elements in electronic integrated circuits, causing transient errors to occur, such as corrupted data in memory, or incorrect behavior of a CPU. Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside This has been a problem in high-altitude electronics, such as in satellites, but as transistors become smaller it is becoming an increasing concern in ground-level equipment as well. ^[8]

To alleviate this problem, Intel has proposed a cosmic ray detector which could be integrated into future high-density microprocessors, allowing the processor to repeat the last command following a cosmic ray event. A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated ^[9]

Significance to space travel

Galactic cosmic rays are one of the most important barriers standing in the way of plans for interplanetary travel by crewed spacecraft. See Health threat from cosmic rays. The health threat from cosmic rays is the danger posed by Cosmic rays generated by the Sun and other stars to astronauts on Interplanetary missions Cosmic

Role in lightning

Cosmic rays have been implicated in the triggering of electrical breakdown in lightning. Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or It has been proposed that essentially all lightning is triggered through a relativistic process, "runaway breakdown", seeded by cosmic ray secondaries. Runaway breakdown is a theory of Lightning initiation proposed by Alex Gurevich in 1992. Subsequent development of the lightning discharge then occurs through "conventional breakdown" mechanisms. ^[10]

Role in climate change

Whether cosmic rays have any role in climate change is disputed. Different groups have made different arguments regarding the role of cosmic ray forcing in climate change.

Shaviv et al. have argued that galactic cosmic ray (GCR) climate signals on geological time scales are attributable to changing positions of the galactic spiral arms of the Milky Way, and that cosmic ray flux variability is the dominant climate driver over these time periods. ^[11][12] They also argue that GCR flux variability plays an important role in climate variability over shorter time scales, though the relative contribution of anthropogenic factors in relation to GCR flux presently is a matter of continued debate. ^[13] Because of uncertainty about which GCR energies are the most important drivers of cloud cover variation (if any), and because of the paucity of historical data on cosmic ray flux at various ranges of energies, controversies remain. ^[14]

Henrik Svensmark et al. Henrik Svensmark is a Physicist at the Danish National Space Center in Copenhagen who studies the effects of cosmic rays on cloud formation have argued that solar variations modulate the cosmic ray signal seen at the earth and that this would affect cloud formation and hence climate. Cosmic rays have been experimentally determined to be able to produce ultra-small aerosol particles,^[15] orders of magnitude smaller than cloud condensation nuclei (CCN). Cloud condensation nuclei or CCN s (also known as cloud seeds) are small particles (typically 0 Whether this mechanism is relevant to the real atmosphere is unknown; in particular, the steps from this to modulation of cloud formation and thence climate have not been established. A cloud is a visible mass of droplets or frozen crystals floating in the atmosphere above the surface of the Earth or another Planetary body The analogy is with the Wilson cloud chamber, however acting on a global scale, where earth's atmosphere acts as the cloud chamber and the cosmic rays catalyze the production of CCN. The cloud chamber, also known as the Wilson chamber, is used for detecting particles of Ionizing radiation. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five The cloud chamber, also known as the Wilson chamber, is used for detecting particles of Ionizing radiation. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Cloud condensation nuclei or CCN s (also known as cloud seeds) are small particles (typically 0 But unlike a cloud chamber, where the air is carefully purified, the real atmosphere always has many CCN naturally. Various proposals have been made for the mechanism by which cosmic rays might affect clouds, including ion mediated nucleation, and indirect effects on current flow density in the global electric circuit (see Tinsley 2000, and F. Yu 1999). Claims have been made of identification of GCR climate signals in atmospheric parameters such as high latitude precipitation (Todd & Kniveton), and Svensmark's annual cloud cover variations, which were said to be correlated to GCR variation.

That Svensmark's work can be extrapolated to suggest any meaningful connection with global warming is disputed:^[16]

At the time we pointed out that while the experiments were potentially of interest, they are a long way from actually demonstrating an influence of cosmic rays on the real world climate, and in no way justify the hyperbole that Svensmark and colleagues put into their press releases and more 'popular' pieces. Even if the evidence for solar forcing were legitimate, any bizarre calculus that takes evidence for solar forcing of climate as evidence against greenhouse gases for current climate change is simply wrong. Whether cosmic rays are correlated with climate or not, they have been regularly measured by the neutron monitor at Climax Station (Colorado) since 1953 and show no long term trend. No trend = no explanation for current changes. ^[17]

More recently a Lancaster University study produced further compelling evidence showing that modern-day climate change is not caused by changes in the Sun's activity. Lancaster University (officially " The University of Lancaster " is a British University in Lancaster, Lancashire, ^[18]

See-also Global warming#Solar variation. Global warming is the increase in the average measured temperature of the

Cosmic rays and fiction

Because of the metaphysical connotations of the word "cosmic", the very name of these particles enables their misinterpretation by the public, giving them an aura of mysterious powers. Were they merely referred to as "high-speed protons and atomic nuclei" this might not be so.

In fiction, cosmic rays have been used as a catchall, mostly in comics (notably the Marvel Comics group the Fantastic Four), as a source for mutation and therefore the powers gained by being bombarded with them. Marvel Comics is an American comic book company owned by Marvel Publishing Inc The Fantastic Four is a fictional Superhero team appearing in Comic books published by Marvel Comics. In biology mutations are changes to the Nucleotide sequence of the Genetic material of an organism

Also, in the book Atlas Shrugged by author Ayn Rand, Dr. Atlas Shrugged is a novel by Ayn Rand, first published in 1957 in the United States Ayn Rand (ˈaɪn ˈrænd &ndash March 6 1982 born Alisa Zinov'yevna Rosenbaum (Алиса Зиновьевна Розенбаум was a Russian born American Robert Stadler's research of cosmic rays is said to have contributed to Project X: a weapon of mass destruction.

See also

• Environmental radioactivity
• Cosmic ray spallation

Notes

References

External links

• Particle Data Group review of Cosmic Rays by W. The High Resolution Fly's Eye or HiRes detector was an Ultra-high-energy cosmic ray observatory that operated in the western Utah desert from May 1997 until -M. Yao et al. , Journal of Physics G 33, 1 (2006).
• Introduction to Cosmic Ray Showers by Konrad Bernlöhr.

• NOAA FTP: Lal, D. , et al. , 2005. Data on cosmic ray flux derived from C14 concentrations in the GISP2 Greenland ice core. An ice core is a Core sample from the accumulation of snow and ice over many years that have re-crystallized and have trapped air bubbles from previous time periods
• BBC news, Cosmic rays find uranium, 2003.
• BBC news, Rays to nab nuclear smugglers, 2005.
• BBC news, Physicists probe ancient pyramid (using cosmic rays), 2004.
• Shielding Space Travelers by Eugene Parker.
• Anomalous cosmic ray hydrogen spectra from Voyager 1 and 2
• Anomalous Cosmic Rays (From NASA's Cosmicopia)
• Review of Cosmic Rays
• Composition of Solar cosmic rays
• "Who's Afraid of a Solar Flare? Solar activity can be surprisingly good for astronauts." Oct. 7, 2005, at Science@NASA]

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