Feb. 21, 2008 -- The universe is a gigantic sausage grinder -- with galaxies chopping and twisting light in all sorts of ways, according to a new study.
Astronomers announced this week the discovery of no less than 67 galaxies caught in the act of mangling the light from far more distant galaxies in a patch of sky just nine times that of the area taken up by a full moon.
If the discovery holds true for the rest of the heavens, there ought to be almost 500,000 more such cases of distorted, gravitationally "lensed" and magnified light from the early universe.
That's great news for astronomers because galactic lensing situations are a lot more than cosmic curiosities. They are also astronomers' only way of gathering light from some very early galaxies -- even if it's sometimes twisted and shredded like a flag in a hurricane.
"There are some that are perfect rings," said Caltech astronomer Peter Capak, a member of the large, international team of researchers who worked on the COSMOS project, which identified the galactic lenses.
The rings are cases where a more distant galaxy is probably directly behind the middle-ground galaxy's center of mass and gravity. The light is bent evenly into a ring around that galactic gravitational well.
Other partial rings and blobs, and even double and triple images of the most distant galaxies created by the gravitational lenses, suggest lumpy or asymmetrical galactic lenses, Capak explained. To sort out exactly how these distortions are created, researchers are working on recreating them with computer models.
The fact that the tortured light is genuinely from more distant galaxies and not part of the middle-ground galaxies is easily sorted out by looking at the "red shifts" of their light. This is the shifting of telltale element lines in the spectrum of light toward the red side of the rainbow. The higher the red shift, the further the object.
"People have used this technique to see galaxies 20 to 30 times fainter" than would otherwise be visible to current telescopes, Capak told Discovery News.
That means those rings and arcs are magnified light from galaxies that has taken more then 10 billion years to reach Earth. And if the sky is actually loaded with hundreds of thousands of these galactic lenses, there's a lot of information about early galaxies out there just waiting to be collected.
Another use for the gravitational lenses is in weighing the nearer galaxies that are doing the lensing. Since the lensing effect is caused by gravity, and gravity is directly related to matter, the effect is a great way to begin a genuine survey of large numbers of galaxies, explained Nick Scoville, head of the COSMOS project.
The COSMOS project combined data from the Hubble Space Telescope, Spitzer Space Telescope, XMM-Newton spacecraft, Chandra X-ray Observatory, Very Large Telescope, Subaru Telescope, and other observatories.
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