Video Karl Gebhardt, HETDEX Project Scientist, explains what dark energy is. Play video |
GlossaryLight-year A unit of length used by astronomers to measure great cosmic distances. One light-year is equal to the distance light travels in one year, which is about 5.88 trillion miles or almost 800 times the diameter of our solar system. The nearest star is a mere four light-years away, while the nearest large galaxy lies about 2.5 million light-years from Earth. Astronomers also use another unit, the parsec, which is equivalent to 3.26 light-years. |
Media Gallery
Find more images, video, and podcasts in the gallery. |
Feedback | Credits | Donate | UT Department of Astronomy| Texas Cosmology Center
 |
   |
 |
 |
Copyright ©2008-2010 McDonald Observatory. HETDEX is a collaboration of The University of Texas at Austin, Pennsylvania State University, Texas A&M University, Universitats-Sternwärte Munich, Astrophysical Institute Potsdam, and Max-Planck-Institut fuer Extraterrestrische Physik. Financial support is provided by the State of Texas, the United States Air Force, and the generous contributions of many private foundations and individuals.
