On average, people in the U.S.A. are exposed to about 3.6 milliSieverts of radiation each year.
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Windows to the Universe original artwork using data from the National Council on Radiation Protection and Measurements.

Radiation

Radiation comes in two basic types: electromagnetic radiation transmitted by photons, and particle radiation consisting of electrons, protons, alpha particles, and so forth.

Electromagnetic radiation, transmitted as photons, includes everything from relatively benign radio waves to dangerous and powerful X-rays and gamma rays. Energy levels across the electromagnetic spectrum vary inversely with wavelength.

Particle radiation involves fast-moving sub-atomic particles, such as electrons, protons, and nuclei (ions) of Helium and heavier elements.

Exposure to too much radiation of various types can be harmful to humans and other living things. Radiation can also fry the electronics in spacecraft, disabling them.

Last modified October 27, 2006 by Randy Russell.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA