Author: Sarah Lightfoot Vidal
Institution: Drexel University
Date: November 2010
The August 20th issue of Science released new information on a method used to accurately measure dark energy. This method, which was developed by NASA (National Aeronautics and Space Administration) and the European Space Agency, essentially advances our understanding of what dark energy actually does.
Dark energy accounts for 72% of the entire universe. However, since it is so hard to quantify, there is hardly any data to explain it. On the other hand, dark matter, which represents 24% of the universe, can be studied via its tangible gravitational effect. The remaining 4% are comprised of planets, moons, stars, people, and the rest of the "visible" universe as we know it.
NASA has developed a method to utilize the Hubble Space Telescope as a giant magnifying lens. Using this method, researchers examined Abell 1689, a galaxy cluster. The gravity therein caused the galaxies behind Abell to appear distorted when photographed multiple times.
Eric Jullo of NASA's Jet Propulsion Laboratory said, "You can literally see gravitation and dark energy bend the images of the background galaxies into arcs." Researchers can now measure the degree to which dark energy causes light to bend around these galaxies.
Dark energy was first discovered in 1988, when it was attributed to the ever-increasing expansion of the universe. Previous methods of observation relied heavily upon terrestrial measurements. These measurements described how quickly galaxies are moving away from us. This new method, however, involves mapping the Abell 1689 cluster using the terrestrial approach as well as the new dark-energy maps formed by the magnifying lens.
This magnifying cosmic lens seeks to explain how and why dark energy functions the way it does. Due to this international cooperation between NASA and the European Space Agency, 96% of our universe may finally be understood with more research in this field.
References:
http://www.jpl.nasa.go/news/news.cfm?release=2010-272
Author: Sarah Lightfoot Vidal
Reviewed by: Karuna Meda and Yangguang Ou
Published by: Maria Huang