What is background radiation and why is it present?
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background radiation is naturally occuring radioactive elements that exist in nature.\n\nWhy is it present... good grief that's a good question. God, this is where you would step in with an explanation lol
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There are many types of electromagnetic radiation. Some we can see, which we call light. Some is lower frequency, like infrared radiation, which is the heat we feel from sunlight, or from a campfire or a stove. Some is higher frequency , like ultraviolet radiation, the radiation. Electromagnetic radiation can travel through space. It does not need any propagation medium to travel in.
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Radio waves are a form of electromagnetic radiation, created whenever a charged object (in normal radio transmission, an electron) accelerates with a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum. In radio, this acceleration is caused by an alternating current in an antenna. Radio frequencies occupy the range from a few tens of hertz to three hundred gigahertz, although commercially important uses of radio use only a small part of this spectrum.[1]\n\nElectromagnetic radio spectrum \n\nOther types of electromagnetic radiation, with frequencies above the RF range, are microwave, infrared, visible light, ultraviolet, X-rays and gamma rays. Since the energy of an individual photon of radio frequency is too low to remove an electron from an atom, radio waves are classified as non-ionizing radiation.\n\nMobile phones and the network they operate under vary significantly from provider to provider, and even from nation to nation. However, all of them communicate through electromagnetic radio waves with a cell site base station
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Measuring the background radiation.\nCalculations involving half life.\nCalculating the energy of fusion and fission reactions.
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X-rays are absorbed by the topmost levels of the earth's atmosphere.\nThe same applies to the gamma radiation emitted by the sun.\n\nWhen the incoming radiation strikes the top of the atmosphere, it interacts with the air molecules and is absorbed (by being broken into a shower of exotic particles, none of which exist for long enough to reach the surface of the planet)\n\nThere are two windows for which radiation reaches the ground, One starting at UV through to visible light and to Infrared, and the Radiowave window which satellites communicate through.
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Cherenkov radiation results from particles traveling faster than the speed of light _in a medium_. The particles are still not traveling faster than THE speed of light, which is more fully described as the speed of light in a vaccuum. Thus, the only implications of this is that the water tanks around nuclear reactors glow blue (which, if you haven't seen it, is really freaking cool).
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We can see the cosmic background radiation. Contrary to what many would say this is not the big bang itself, but the moment the first atoms formed (when protons bonded with electrons) and photons of light could freely travel through space. This happend about 300,000 years AFTER the big bang. The universe was about the size of the Milky Way Galaxy at that time.\n\nWe cannot see before this moment in time. Before this, information in the form of photons could not propagate. The actual moment of the big bang will forever be beyond reach.
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The radiations emitted from the sun and also the earth are usually blocked by layers of atmospheric gases and prevent them from escaping into space.This causes 'GLOBAL WARMING'-due to the reflected radiations.This is also known as 'GREEN HOUSE EFFECT'.
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Radiation comes in many forms.  Light and radio waves are radiation, but they're not energetic enough to cause problems in low doses.  Of course, with enough light you can burn someone, and enough radio waves can do similar, but it's not as much of a problem as more energetic forms of radiation. \n\nForms of radiation which have enough energy or have charge characteristics such that they can remove an electron from a chemical bond are called "ionizing radiation", also sometimes called "hard radiation".  These are the dangerous forms of radiation.  \n\nThere are three types of nuclear radiation, gamma, beta, and alpha, all of which are ionizing.  \n\nGamma radiation is fundamentally the same as light, but is of a much higher energy, such that it can break a molecular bond.  It's very energetic, but electrically neutral.  Gamma radiation can penetrate materials better than other forms of nuclear radiation.  Gamma rays come from either reorganization of an energized nulceus, in much the same way that visible light can be emitted by reorganization of electrons in the electron orbitals, and can also be produced when an anti-electron kicked out by the nucleus collides with an electron and undergoes matter/antimatter annihilation.\n\nBeta radiation is high energy electrons kicked out of the atomic nucleus when a neutron converts to a proton.  It has a fair amount of energy, plus a negative one charge.  It doesn't travel very far and is fairly easy to shield against, but it can cause a lot of damage.\n\nAlpha radiation is the least penetrating of all, being stopped by ~5 cm of air, or a thin layer of materials, like a latex glove or a sheet of paper.  Alpha rays have a large charge, however, and if absorbed by living cells can be very dangerous.  Alpha rays are two protons and two neutrons, basically a helium nucleus, spit out of a larger nucleus at a fairly high energy.  \n\nAll of these forms can break a chemical bond, and if this happens in living tissue, and it happens enough, it can kill you.  Proteins necessary for cellular functions get snipped in two, or get ionized in a spot that causes them to fold and twist and become non-functional, DNA can be broken, and cell membranes can be damaged, causing holes in cells which can result in cell death.  It's something like being shot with a shotgun, only at the molecular level.  \n\nAcute radiation poisoning, the amount needed to kill you in a short period of time, is somewhere around a one time exposure of 200 REM or more.  A REM is a unit of radiation exposure based on total radiation of various types, and the absorption of human bodies to that form of radiation. It's a complex number to come up with, and much of the data we have to determine REM exposure is based on empirical data.  Acute radiation poisoning is a terrible way to die.  The exact symptoms vary depending on the type and total dose of radiation absorbed, but generally speaking protein synthesis is disrupted causing problems with rapidly replaced cells, like blood cells plus loss of hair and skin problems, cells die by the millions, tissue structure breaks down, internal bleeding occurs, organs fail, your brain can be damaged enough that you suffer neurological problems like seizures and dementia, and then you die.  It can take a over a week to kill you, it's horribly painful, and there's no treatment that can cure you. \n\nLower doses of radiation can cause enough damage that cancer can arise later, or can cause various forms of tissue damage and impairment, depending on the dose, and where you absorbed the radiation in your body.  The damage can be very variable, which is one reason it's difficult to say just how much radiation it takes to cause a problem.  There are some treatments that can minimize the damage of low doses of radiation, but it depends a lot on what type of radiation you were exposed to.  \n\nAlso, all living things do have cellular repair mechani
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The sun converts millions of tons of matter into energy every second via fussion processes; this energy is radiated out in every direction in the form of photons and a slew of other particles. \n\nWhen these photons reach earth, we call it "incident light". Light is easily reflected, refracted, and absorbed by many materials on earth, and at every level of interaction, energy is lost to heat.\n\nEdit - what's with all this "pan heating an egg" stuff? What does that even mean?
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Gamma rays, heat and, in the case of a few highly-radioactive elements, light; they glow in the dark.  Beta particles which are high-energy electrons.   Their kinetic energy can be converted into light by a phosphor such as zinc sulphide, or if they enter a transparent medium with a high refractive index, they emit blue Cerenkov radiation.  Radioactive materials are warmer than their surroundings because alpha particles, beta rays and neutrons are all fast-moving particles and when they are absorbed their kinetic energy is converted into heat.  In a nuclear reactor the heat is used to raise steam which drives a turbine.  In the thermionic generators used on deep space probes it is converted directly into about 200 watts or so of electricity.
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HZE Particle\n\nHigh-energy radiation or particles from extraterrestrial space that strike the earth, its atmosphere, or spacecraft and may create secondary radiation as a result of collisions with the atmosphere or spacecraft.
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I assume they want to know about nuclear radiation.  Some basic facts:\n- 3 types are alpha, beta and gamma\n- All are found in nature, you carry it around in you, it comes from just about all natural materials to some small degree.\n- Naturally occuring radiation is little to worry about, we evolved with it and our bodies can handle it.\n- In most areas of the world, natually occuring radiation hits each square inch of your body between 12-18 times per minute!  Radiation can not be felt by the body.\n- Alpha is the biggest particle (nucleaus of a helium atom) and moves slowly.  Not enough speed to even penetrate the layer of normal dead skin on your body.  \n- Beta is an electron moving at higher speeds.  It too is motly blocked by skin, but in high dosages can start to become a problem.\n- Gamma is not a particle, but a wave like light (but much higher frequency).  X-rays and cosmic rays are the best known.  Cosmic rays are the most common type of radiation that hit our bodies per above.  It comes from high speed particles interacting with our atmosphere.  \n- The small amounts of natural radiation we encounter everyday is not a significant problem, but concentrated sources of radiation are.  These have historically included x-rays, byproducts of nuclear bombs or reactors, mishandled medical/agricultural/engineering equipment.  \n- Ingested alpha and beta emitting materials are dangerous even in tiny amounts and can cause cancer.
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Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of ultrarelativistic (i.e., moving near the speed of light) electrons through magnetic fields. This may be achieved artificially by storage rings in a synchrotron, or naturally by fast moving electrons moving through magnetic fields in space. The radiation typically includes infrared, optical, ultraviolet, x-rays.
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Cerenkov radiation is 'braking radiation.' It happens when particle are travelling faster the speed of light in some medium. The energetic particles slam into atoms in the medium and slow down abruptly. As you may be aware, when you accelerate a charge, it radiates energy. This is no exception -- the particle radiates light, called Cerenkov radiation.
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Not even remotely true.\n\nAll things are radiocative. The only thing in this universe that isn't radioactive is the small amount of hydrogen that scientists have refined to not be radiocative.\n\nThis "radioactivity of everything" is what we call the background radiation level. It varies from place to place but everywhere has a background radiation level, and the insides of people or other organisms are no exception.\n\nPeople become radioactive simply because the food they eat is radioactive. The food is radiocative because the ground and air it came from is radiocative.\n\nThe ground is radioactive because the matter the Earth was made of came from a supernova. And supervova is just a really, really big atomic bomb.\n\nThe air is radioactive partly because of that supernova but mostly because the sun is also basically a really big nuclear bomb. On the ground we are protected from all the worst radaiation that bomb puts out. In the upper atmosphere the air is not protected. It gets zapped with masive amounts of radiation every day  and is fairly radioactive as a result.\n\nWhen plants take minerals out of the soil those minerals are slightly radioactive from the supernova that created the Earth. When plants take carbon out of the air that carbon is  radioactive from being zapped by nuclear radiatioon from the sun. When the plants use those things to build more plants the plants become radioactive. When animals eat the  radioactive plants and use that material to build animal bodies the animals become radicoative.\n\nAnd when people eat radiocative plants and animals our bodies become radiocative.\n\nEverything in the universe is radiocative, even us. The only thing that varies is how radioactive they are.
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Radiation from thousands of nuclear bomb tests.  If you wait until night the green ones will glow.  Or maybe they're just different colors like black people and white people.