An Eye-Opening Look at Dark Energy
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Image courtesy of Dark Energy Survey Collaboration
Zoomed-in image from the Dark Energy Camera of the barred spiral galaxy NGC 1365, in the Fornax cluster of galaxies, which lies about 60 million light years from Earth.
There's magic in the moment of opening one's eyes—especially for the first time: New sights, new possibilities, even new worlds spring into view.
For technology, that's also true. On September 12th, the 'eyes' of a U.S. Department of Energy (DOE) Office of Science-supported camera were opened, taking in their first light and hopefully leading the way to a better understanding of our universe and the forces that shape it.
Those eyes belonged to the Dark Energy Camera (DECam), a unique and essential instrument in the Dark Energy Survey, a partnership between the National Science Foundation and the DOE Office of Science.
The special camera was developed by researchers at DOE’s Fermi National Accelerator Laboratory (Fermilab), working in collaboration with scientists at three other DOE labs, Lawrence Berkeley National Laboratory (Berkeley Lab), Argonne National Laboratory, and SLAC National Accelerator Laboratory. The DECam is the most powerful survey instrument of its kind. It images light from a primary mirror that's 4 meters across. Among the camera’s jaw-dropping statistics, it has a weight of 4-5 tons and contains some 570 million pixels, which allow it to capture light from more than 100,000 galaxies up to eight billion light years away…with each 'snapshot.'
While DOE researchers have provided the camera, NSF is providing the telescope and will provide the data management. In all, the Dark Energy Survey involves 25 institutions from around the world.
Mounted in the Blanco Four-Meter Telescope, at the National Science Foundation's Cerro Tololo Inter-American Observatory in Chile, the DECam was specifically designed to capture the light of distant galaxies. That light is of great interest to the survey team since it can reveal how the universe is expanding…at an accelerating rate.
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Image courtesy of Dark Energy Survey Collaboration
The Dark Energy Camera, mounted on the Blanco telescope in Chile.
That space itself is spreading apart at an accelerating pace was discovered by two independent teams of researchers, one of which was led by Berkeley Lab's Dr. Saul Perlmutter. The finding was a real eye-opener for scientists, who had previously thought that the attractive force of gravity would eventually slow things down. In fact, three scientists, including Dr. Perlmutter, won the 2011 Nobel Prize in Physics for that discovery.
Scientists now believe that the accelerating expansion is being driven by a mysterious force called dark energy. But they're still striving to understand its nature, and that's where the DECam comes in. By giving a look at distant galaxies—how they are racing away from one another across space and time—the camera will hopefully reveal more about how dark energy is shaping the universe at large scales. And that will tell us more about where we are today, how we got there, and where we might go tomorrow.
The first light the DECam took in came from galaxies some eight billion light years away. It is undergoing further testing, and is expected to begin its five-year Dark Energy Survey in December. Over that time, it is expected to discover and measure 4,000 supernovae, 100,000 galaxy clusters and 300 million galaxies.
That's the Office of Science and its labs: Opening eyes…and opening worlds.
The Department's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information please visit http://science.energy.gov/about. For more information about Fermilab, please go to: http://www.fnal.gov/. And for more information on the DES, please go to: http://www.darkenergysurvey.org/.
Charles Rousseaux is a Senior Writer in the Office of Science.
