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

Meteorites II Measuring the age of the solar system Saturday, April 18, 2015
Moon and Jupiter Traveling to a deadly planet Wednesday, October 15, 2014
More Moon and Jupiter Wrapping a spacecraft in plastic Friday, October 25, 2013
Storm Probes Plunging into the danger zone Thursday, December 20, 2012
Van Biesbroeck's Star Hunting up a faint cosmic bulb Saturday, July 16, 2011
Moon and Jupiter Shielding an entire planet Saturday, May 28, 2011
Underground Astronomy II Blocking out interference Wednesday, March 2, 2011
Shields Up! Protection against a dangerous universe Friday, December 17, 2010
Dangerous Space One of the hazards of space travel Thursday, December 16, 2010

Featured Images

Jupiter's radiation belts
Jovian Shields Wednesday, October 15, 2014
Van Allen Probes and Earth's Van Allen radiation belts
Dangerous Exposure Thursday, December 20, 2012
Shields like those of the USS Enterprise may protect real space travel
Shields Up! Friday, December 17, 2010


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