Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS

NOVA Online (see text links below)
Death Star  
A Self-Guided Tour of the Electromagnetic Spectrum

 
Spectrum - Gamma ray

Gamma rays
It's not easy to imagine how high the frequency of a high-energy gamma ray is. During the time it takes for its wave to go through one cycle, a gamma-ray wave traveling at the speed of light will travel only the width of a proton, a tiny particle found within the nucleus of an atom.

Gamma rays are created throughout the universe in violent explosions. On Earth, they originate from the decay of radioactive elements and within particle accelerators, which are devices that smash together subatomic particles propelled at velocities close to the speed of light.


Sterilizer
Like ultraviolet radiation and X-rays, gamma rays can kill microorganisms and are used to sterilize food and other objects, such as medical instruments and equipment. Gamma radiation is also a treatment for cancer.


Gamma image of entire sky
High-energy gamma-ray photons are relatively scarce, and it takes many photons to create a meaningful image of an object in space. For this reason, there are not many images of astronomical objects in gamma wavelengths. This one, a gamma-ray image of the entire sky as seen from earth, took 18 months to create.


intro | radio | microwave | infrared | visible light | ultraviolet | x-ray | gamma



Printer-Friendly Format   Feedback

One Astronomer's Universe | A Bad Day in the Milky Way
Catalogue of the Cosmos | Tour the Spectrum
Resources | Transcript | Site Map | Death Star Home

Search | Site Map | Previously Featured | Schedule | Feedback | Teachers | Shop
Join Us/E-Mail | About NOVA | Editor's Picks | Watch NOVAs online | To print
PBS Online | NOVA Online | WGBH

© | Updated January 2002
 

Support provided by

For new content
visit the redesigned
NOVA site

Shop Teachers Feedback Schedule Previously Featured Site Map Search NOVA Home Death Star Home Site Map Death Star Home Visible light Visible light X-rays Ultraviolet Infrared Microwave Radio