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 - ultraviolet

Ultraviolet
There are many sources of ultraviolet light in the universe—the sun is a prime example.

Though we can't see ultraviolet light, some animals can. Some insects, for example, can see ultraviolet patterns in flowers.

Ultraviolet radiation has some important uses. Because it can kill bacteria and viruses, it is used to sterilize objects such as medical instruments, the air used in operating rooms, and food containers.


fluorescent lighting
Although ultraviolet radiation is not visible to our eyes, we do use it for artificial lighting. Fluorescent lights emit a bright white light, but what is generated within the long narrow tubes is mainly ultraviolet light. This ultraviolet light strikes the inside surface of the tube, which is coated with a phosphor powder. When the ultraviolet radiation strikes the phosphor, the coating emits light in the visible spectrum.


sun viewed via ultraviolet
Viewing the sun in ultraviolet wavelengths allows astronomers to study its corona, or outermost atmosphere, as well as flares and mass ejections. The brightest areas in this image show the sun's hottest regions.

Next: X-rays


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 Gamma rays X-rays Infrared Microwave Radio