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Distant galaxies show a mature Universe in childhood NASA NEWS RELEASE Posted: March 20, 2005 Scientists have discovered the most distant massive structure yet detected in the Universe, a fully formed galaxy cluster containing hundreds, if not thousands, of galaxies. The discovery is evidence that the Universe's elegant hierarchal structure of stars, galaxies and clusters formed quickly after the big bang, far earlier than most astronomers thought possible just a few years ago.
"We are quite surprised to see that exquisite structure like this could exist at such early epochs," said Mullis, who is also lead author on a report about this finding in an upcoming issue of The Astrophysical Journal. "We see an entire network of stars and galaxies in place at just a few billion years after the big bang, like a kingdom popping up overnight on Earth." The newly discovered cluster is about 9 billion light years from Earth, a half billion light years farther out than the previous record holder. This means the cluster was mature when the Universe was only 5 billion years old, and that the stars and galaxies formed and assembled into a cluster within only a few billion years. The Universe is now 13.7 billion years old. "We have underestimated how quickly the early Universe matured into its present-day incarnation," said Dr. Piero Rosati at ESO headquarters in Garching, Germany, a co-author on the report. "The Universe grew up fast." The scientists said this discovery might be the tip of the iceberg. Their results are based on a first peek at archived XMM-Newton data from the past four years. Other clusters undoubtedly lie hidden in the data archive waiting to be discovered, they said. Galaxy clusters contain hundreds to thousands of galaxies gravitationally bound to each other. Our Milky Way galaxy resides in a relatively low-density region of the Universe, part of a "local group" of galaxies but apparently not bound to the nearby Virgo cluster. Scientists study the distribution and growth rate of galaxy clusters to understand the overall structure and evolution of the Universe. Most of the ordinary matter in galaxy clusters takes the form of hot, tenuous gas in between galaxies. This gas is invisible to optical telescopes but can be detected with large, orbiting X-ray observatories, such as XMM-Newton. Mullis said that a 12-hour XMM-Newton observation of a nearby galaxy revealed tantalizing evidence of a galaxy cluster far in the background. Knowing where to look, his team used the powerful ESO VLT in the Atacama Desert in Chile to find an optical counterpart. Sure enough, the team found dozens of galaxies associated with this X-ray emission. The VLT data established the distance to the cluster, at a redshift of 1.4, corresponding to about 9 billion light years away. The galaxies were reddish, elliptical types, an indication that they were already several billion years old and filled with older red stars. The cluster itself was largely spherical, a sign that it was well formed. Proto-clusters, which are clusters in the making, have been seen over 10 billion light years away. The new finding is the best evidence yet of when these wild proto-clusters reached maturity. The relative ease of discovery, based on archived data, implies that the team could build a large sample size of exceedingly distant clusters. This would allow scientists to directly test competing theories of structure formation and evolution. The team is currently pursuing detailed follow-up observations from both ground and space-based observatories. "This discovery encourages us to search for additional distant clusters using this same efficient technique," said team member Dr. Hans Bohringer of Max Planck Institute for Extraterrestrial Physics (MPE) in Garching. "It also shows great promise for experiments under construction, such as the Atacama Pathfinder Experiment. Such diligent searching will ultimately place strong constraints on fundamental parameters of the Universe." Other team members include Rene Fassbender and Dr. Peter Schuecker (MPE) and Drs. Axel Schwope and Georg Lamer of the Astrophysical Institute of Potsdam. |
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The first Boeing Delta 4-Heavy rocket ignites and lifts off from pad 37B at Cape Canaveral Air Force Station on its demonstration test flight as seen through this sequence of images from a sound-activated still camera.
A second sound-activated still camera placed at pad 37B by Spaceflight Now photographer Ben Cooper provides a different view of the Delta 4-Heavy rocket launch.
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An onboard video camera mounted to the Atlas 5 rocket's first stage captures this view of the spent solid-fuel boosters separating.
This view of the Atlas 5 launch was recorded from the Kennedy Space Center Press Site. (1min 27sec file)
The Boeing Delta 4 rocket to launch the next GOES geostationary U.S. weather satellite is rolled to Cape Canaveral's pad 37B for its spring blastoff. (2min 08sec file)
The pad erector arm lifts the Delta 4 rocket upright, standing the vehicle onto the launch table. (4min 00sec file)
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The astronauts don coveralls and go into space shuttle Discovery's payload bay for further examinations during the Crew Equipment Interface Test in the orbiter hangar. (1min 25sec file)
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