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Radiation

Energy that travels through space at the speed of light. The total range of electromagnetic wavelengths and frequencies is called the electromagnetic spectrum. Our eyes are sensitive to a sliver of the electromagnetic spectrum we call visible light, from red to blue. Beyond the blue end, as wavelength decreases and frequency increases, lie ultraviolet light, X-rays, and gamma-rays. In the other direction past red, as wavelength increases and frequency decreases, lies infrared, microwave, and radio regions of the electromagnetic spectrum. Radio waves are the longest, extending on the order of meters, while X-rays and gamma-rays are the shortest, on the order of atomic size. Light wavelengths are measured in microns, millionths of meters. For all forms of electromagnetic radiation, the speed of light must remain constant, regardless of wavelength or frequency.

Radio Programs

More Reionization An early light in the young universe November 4, 2016

Reionization Giving the universe a charge November 3, 2016

Moon and Jupiter Danger from giant volcanoes June 11, 2016

Van Allen Belts Earth’s dynamic radiation belts May 4, 2016

Meteorites II Measuring the age of the solar system April 17, 2015

Moon and Jupiter Traveling to a deadly planet October 14, 2014

More Moon and Jupiter Wrapping a spacecraft in plastic October 24, 2013

Storm Probes Plunging into the danger zone December 19, 2012

Van Biesbroeck's Star Hunting up a faint cosmic bulb July 15, 2011

Moon and Jupiter Shielding an entire planet May 27, 2011

Underground Astronomy II Blocking out interference March 1, 2011

Featured Images

Jupiter's radiation belts

Jovian Shields October 15, 2014

Van Allen Probes and Earth's Van Allen radiation belts

Dangerous Exposure December 20, 2012

Shields like those of the USS Enterprise may protect real space travel

Shields Up! December 17, 2010