By Definition
High Definition
Standard Definition
By Length
Full (4-12 min)
Short (1-4 min)
By Date
2015 | 2014 | 2013 | 2012 |
2011 | 2010 | 2009 | 2008 |
2007 | 2006
By Category
Solar System
Stars
White Dwarfs
Supernovas
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Quasars
Groups of Galaxies
Cosmology/Deep Field
Miscellaneous
HTE
STOP
Space Scoop for Kids!
Chandra Sketches
Light
Subscribe
How To
Apple iTunes
RSS Reader
Web Shortcuts
Chandra Blog
RSS Feed
Chandra Mobile
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Recent Podcast
Light Beyond the Bulb: Over and Beyond the Rainbow
Light Beyond the Bulb: Over and Beyond the Rainbow
While scientists and philosophers have tried to figure out exactly what light is for millennia, it's only been in the past several hundred years or so that we've really started to figure it out. (2015-07-01)
Audio Podcasts: "Touch the Invisible Sky"

Simon Steel reads "Touch the Invisible Sky" Braille book (Introduction)

View/Listen

The Universe is huge. Almost everything that we know about distant objects in the Universe comes from studying the light that is emitted or reflected by them. On Earth, geologists can study rocks by collecting them. Astronauts traveled to the Moon in 1969 and collected moon rocks, but the stars and galaxies are so far away that the primary way we can learn about them is from their light.

Astronomy is a little like Archaeology. This is because the light from stars and galaxies may take hundreds, thousands or even millions of years to reach our telescopes. We observe that star or galaxy as it looked when the light was emitted, hundreds or thousands or millions of years ago. For example, when astronomers study a galaxy that is 200 million light years away, they are observing that galaxy as it appeared 200 million years ago. Looking out in space is like looking back in time. Fortunately, the stream of light from those stars and galaxies contains an incredible amount of information. Simply by analyzing star light, we can tell the distance, age, size and chemical composition of a celestial object way beyond their grasp. Astronomers are space detectives, intent on solving the mysteries of how galaxies, stars and planets are born, evolve and behave. Perhaps most importantly, the story of the Universe is also the story of us. In unraveling the mysteries of the Universe, we are also beginning to understand our place in our cosmic home.

Return to Audio Podcasts: Touch the Invisible Sky