Ionizing radiation comes from x-ray machines, cosmic particles from outer space and radioactive elements. Radioactive elements emit ionizing radiation as their atoms undergo radioactive decay. Radioactive decay is the emission of energy in the form of ionizing radiation ionizing radiation Radiation with so much energy it can knock electrons out of atoms. The ionizing radiation that is emitted can include alpha particles alpha particles A form of particulate ionizing radiation made up of two neutrons and two protons.
Alpha particles pose no direct or external radiation threat; however, they can pose a serious health threat if ingested or inhaled. Some beta particles are capable of penetrating the skin and causing damage such as skin burns. Beta-emitters are most hazardous when they are inhaled or swallowed. Gamma rays can pass completely through the human body; as they pass through, they can cause damage to tissue and DNA. Radioactive decay occurs in unstable atoms called radionuclides. The energy of the radiation shown on the spectrum below increases from left to right as the frequency rises.
Other agencies regulate the non-ionizing radiation that is emitted by electrical devices such as radio transmitters or cell phones See: Radiation Resources Outside of EPA. Alpha particles come from the decay of the heaviest radioactive elements, such as uranium , radium and polonium. Even though alpha particles are very energetic, they are so heavy that they use up their energy over short distances and are unable to travel very far from the atom.
The health effect from exposure to alpha particles depends greatly on how a person is exposed. Alpha particles lack the energy to penetrate even the outer layer of skin, so exposure to the outside of the body is not a major concern.
Inside the body, however, they can be very harmful. If alpha-emitters are inhaled, swallowed, or get into the body through a cut, the alpha particles can damage sensitive living tissue. Infrared Waves. Reflected Near-Infrared. Visible Light. Ultraviolet Waves. Earth's Radiation Budget. Diagram of the Electromagnetic Spectrum. Recommended Articles. September 24, Solar Eclipse - June 10, June 09, Aurora-Chasing Citizen Scientists Help November 13, Gamma-rays travel to us across vast distances of the universe, only to be absorbed by the Earth's atmosphere.
Different wavelengths of light penetrate the Earth's atmosphere to different depths. Instruments aboard high-altitude balloons and satellites like the Compton Observatory provide our only view of the gamma-ray sky.
Gamma-rays are the most energetic form of light and are produced by the hottest regions of the universe. They are also produced by such violent events as supernova explosions or the destruction of atoms, and by less dramatic events, such as the decay of radioactive material in space.
Things like supernova explosions the way massive stars die , neutron stars and pulsars, and black holes are all sources of celestial gamma-rays.
How do we "see" using gamma-ray light? Gamma-ray astronomy did not develop until it was possible to get our detectors above all or most of the atmosphere, using balloons or spacecraft. The first gamma-ray telescope, carried into orbit on the Explorer XI satellite in , picked up fewer than cosmic gamma-ray photons!
Each individual beam has very little effect on the brain tissue it passes through, but a strong dose of radiation is delivered at the point where the beams meet, according to Mayo Clinic.
One of the more interesting sources of gamma rays are gamma-ray bursts GRBs. These are extremely high-energy events that last from a few milliseconds to several minutes. They were first observed in the s, and they are now observed somewhere in the sky about once a day. Gamma-ray bursts are "the most energetic form of light," according to NASA.
They shine hundreds of times brighter than a typical supernova and about a million-trillion times as bright as the sun. According to Robert Patterson, a professor of astronomy at Missouri State University, GRBs were once thought to come from the last stages of evaporating mini black holes.
They are now believed to originate in collisions of compact objects such as neutron stars. Other theories attribute these events to the collapse of supermassive stars to form black holes. In either case, GRBs can produce enough energy that, for a few seconds, they can outshine an entire galaxy. Because Earth's atmosphere blocks most gamma-rays, they're seen only with high-altitude balloons and orbiting telescopes.
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