February 21, 2008
Largest-ever Dark Matter Structures Found
A University of British Columbia astronomer with an international team has discovered the largest structures of dark matter ever seen. Measuring 270 million light-years across, these dark matter structures criss-cross the night sky, each spanning an area that is eight times larger than the full moon.
"The results are a major leap forward since the presence of a cosmic dark matter web that extends over such large distances has never been observed before," says Ludovic Van Waerbeke, an assistant professor in the Dept. of Physics and Astronomy.To glimpse the unseen structures, the team of French and Canadian scientists "X-rayed" the dark matter, an invisible web that makes up more than 80 per cent of the mass of the universe.
The team used a recently developed technique called "weak gravitational lensing," which is similar to taking an X-ray of the body to reveal the underlying skeleton. The study relied on data gathered from the world's largest digital camera.
"This new knowledge is crucial for us to understand the history and evolution of the cosmos," says Van Waerbeke. "Such a tool will also enable us to glimpse a little more of the nature of dark matter."
The astronomers observed how light from distant galaxies is bent and distorted by webs of dark matter as it travels toward Earth. They then mapped dark matter structures by measuring the distortions seen in these galaxy light patterns.
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