English.news.cn 2010-11-12
LOS ANGELES, Nov. 11 (Xinhua) -- U.S. astronomers have created one of the sharpest and most detailed maps of dark matter in the universe, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.
With the help of NASA's Hubble Space Telescope, the astronomers took advantage of a giant cosmic magnifying glass to create the map, according to the JPL, headquartered in Pasadena, Los Angeles.
They charted the invisible matter in the massive galaxy cluster Abell 1689, located 2.2 billion light-years away, the JPL said.
The cluster's gravity, the majority of which comes from dark matter, acts like a cosmic magnifying glass, bending and amplifying the light from distant galaxies behind it.
This effect, called gravitational lensing, produces multiple, warped, and greatly magnified images of those galaxies, like the view in a funhouse mirror.
By studying the distorted images, astronomers estimated the amount of dark matter within the cluster, said the JPL.
Dark matter is an invisible and unknown substance that makes up the bulk of the universe's mass. A mysterious property of space, dark energy fights against the gravitational pull of dark matter.
Dark energy pushes galaxies apart from one another by stretching the space between them, suppressing the formation of giant structures called galaxy clusters.
One way astronomers can probe this primeval tug-of-war is by mapping the distribution of dark matter in clusters, according to the JPL.
The new dark matter observations may yield new insights into the role of dark energy in the universe's early formative years, the JPL noted.
It said the new results suggest that galaxy clusters may have formed earlier than expected, before the push of dark energy inhibited their growth.
Dark Matter Map This is one of the most detailed maps of dark matter ever made. The location of the dark matter (tinted blue) was inferred through observations of magnified and distorted distant galaxies seen in this picture. NASA
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