At a Glance: Seeing the Invisible—Using Infrared to See Dust

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When light waves travel through clouds of gas and dust, they are stopped and deflected by the cloud's particles.  When infrared light waves travel through clouds of gas and dust, most of them make it to the outside.  

Credits


Star and Planet Formation
 
 
Produced by the Space Telescope Science Institute’s Office of Public Outreach.
 
All images, illustrations, and videos courtesy of NASA, ESA, and STScI except:
 
·       Taurus constellation drawing from Firmamentum Sobiescianum sive Uranographia by Johannes Hevelius, courtesy of the United States Naval Observatory
·       Andromeda Galaxy visible-light image courtesy of NOAO/AURA/NSF
·       Rocket launch image ©2008 ESA-CNES-Arianespace/Photo by Optique Video CSG 
·       Sunrise image copyright Jamie Lee – Fotolia.com
·       Barnard 68 images courtesy of ESO
 
Written by Tracy Vogel
Designed by Marc Lussier 
Music courtesy of Associated Production Music

Transcript


(SPEECH)
[DOWNBEAT MUSIC]

(DESCRIPTION)
Stars and galaxies beyond the curve of a planet.

Text, at-a-GLANCE. SEEING THE INVISIBLE.

A galaxy.

Text, Andromeda Galaxy. VISIBLE LIGHT. Dust in this galaxy hides young stars forming within.

How do we know?

The galaxy in infrared. Many more stars appear.

Text, INFRARED LIGHT. We can see them when we look in infrared light.

How does this work?

Our eyes can only see visible light.

A light spectrum appears on a black background with a wavy line under it.

Text, ULTRAVIOLET. VISIBLE LIGHT. INFRARED.

Left, a man holds a black plastic bag. Right, the same picture in infrared. The man's body glows orange. His hands are visible through the bag.

Text, VISIBLE-LIGHT CAMERA. INFRARED-LIGHT CAMERA. Our bodies are designed to perceive infrared light as heat, but we can also build cameras to detect infrared light.

VISIBLE LIGHT WAVES. Visible light has short wavelengths.

A star shines a beam of light down onto a cloud. Inside the cloud, rays of light bounce off particles or are absorbed.

Text, When they travel through clouds of gas and dust, the light waves are stopped and deflected by the cloud's particles.

One ray of light exits the cloud.

Text, INFRARED LIGHT WAVES.

View the cloud through glasses. It turns purple. Waves emanate from an orange center.

Text, Infrared light has long wavelengths.

A star shines a beam of light onto a cloud. The rays travel through the cloud, avoiding the particles. Most exit the cloud.

Text, When they travel through clouds of gas and dust, most of the light waves make it to the outside.