Photos Andromeda
For more of our series "The Wide Angle," click around in the box to your right: "Get the Wide Angle on Dark Energy." Dec. 16, 2008 -- The next time you find yourself beneath a dark night sky, look up and consider: it might've been a much more crowded place. Were it not for dark energy, a mysterious repulsive force in the universe, our Milky Way galaxy would've long since crashed into its only neighbor, Andromeda. And instead of being lonely travelers in space, the galaxies would be nestled in the Virgo cluster, with hundreds more neighboring galaxies so close they'd be visible to the naked eye. Now a team of researchers have analyzed 85 galactic clusters, measuring how dark energy has influenced their evolution. Over the past five billion years, they found, it has had a profound effect on the clusters' structure, significantly slowing down the rate at which they collapse. "What we see can only be explained with a substantial amount of dark energy," said Alexey Vikhlinin of Harvard University, the team leader. The observations confirm scientists' long-held notion that the strange energy makes up two-thirds of the entire universe. Related Content: The Wide Angle: 10 Things You Didn't Know About Dark Energy The Wide Angle: Dark Energy Doubters The Wide Angle: How to Hunt for Dark Energy The result is also a profound validation for the theory of general relativity, which predicts a consistent force throughout the universe -- known to Einstein as the "cosmological constant" -- that dominates gravity at scales of tens of millions of light-years or more. All 85 clusters appear to show the same effects from dark energy, so relativity emerges unscathed. "The equations of general relativity have never been tested on scales of galaxy clusters," Alexey Vikhlinin said. "Gravity works as expected; that leaves little room for modification." Get More NewsMouse Cloned From Long-Frozen CellResearchers create a mouse from a long-frozen cell. Will the mammoth be next?'Bubble' Could Protect AstronautsScientists say a "bubble" around a Mars-bound spaceship could protect astronauts.Big Reduction of Snowmobiles in Yellowstone ProposedA new plan would cut snowmobile use by 40 percent in Yellowstone.Microbes: Fuel of the Future?A reddish South American microbe is literally breathing fuel, say scientists.DNA Links Remains to Steve FossetDNA tests on two bones found in California confirm they are those of Steve Fossett.Women Carry More Bacteria Than MenSome bacteria prefer women, suggests a new study. But why?Ancient 'Water Monster' Facing ExtinctionA foot-long salamander that was a key part of Aztec legend is threatened by extinction.Grand Canyon's Youth ConfirmedThe Grand Canyon is millions of years younger than previously thought, argue geologists.My Take: E-Voting Not User FriendlyOpinion: Electronic voting machines don't always capture the intent of voters.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.At 40, Brain and Body SlowThe part of the brain in charge of motion starts a gradual slide in middle age.Spiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates. |
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