Stuart Clark, New Scientist News Service
(Translation, Dikla Oren)
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Astronomers have put together the largest and most detailed map of the universe to date. They believe that it undoubtedly shows the presence of dark energy, which penetrates all areas of the universe.
The 200,000D map contains XNUMX galaxies and covers six percent of the sky. The most distant galaxies included in it are two billion light years away. The value of such maps is invaluable, as this large-scale structure of the universe reveals the interplay of cosmic forces over the past thirteen million years.
The new map originates from the SDSS (Solan Digital Sky Survey) project, which is the result of an international collaboration of more than two hundred astronomers from thirteen institutes around the world.
To build the map, astronomers first identified individual galaxies in a wide-angle image of the sky taken by the SDSS's 2.5-meter telescope at Apache Point Observatory in New Mexico.
They then used the telescope's special fiber optic system to record the spectra of up to 608 galaxies at a time, allowing them to calculate the distance to each galaxy and place it on the XNUMXD map.
Until the mid-XNUMXs, most cosmologists believed that the universe was shaped by gravity, created by normal matter and invisible dark matter. So, exploding stars in the depths of the universe implied that a cosmic force was causing the universe to expand. Astronomers called this force "dark energy".
In February 2003, a fusion of a large-scale galaxy map from the Anglo-Australian Redshift Survey of Galaxies (2dF) with information on radiation left over from the Big Bang from NASA's WMAP space probe showed strong evidence for the existence of dark energy.
The new map - the result of the use of different galaxies, tools, staff and data analysis - provides the same result with greater precision, placing the existence of dark energy beyond any doubt. One of the astronomers leading the project, Max Tagmark from the University of Pennsylvania, told the journal "New Scientist": "There is no longer just one set of information to blame. The web of evidence supporting the existence of dark energy is strong. All observations point to the existence of dark energy. "
Carlos Frank from Durham University in England was involved in the 2dF project and he agrees: "The new map provides powerful confirmation that dark energy exists in the universe. Dark energy cannot be disproved now, while a year ago it was not the case."
The results from the map confirm that 70 percent of the universe is dark energy, 25 percent is dark matter and only about five percent is the matter we know, from which the earth and the stars are built.
Since the existence of dark energy has been confirmed by observations, theoretical physicists are tasked with explaining what exactly it is. The SDSS may provide help with this, and astronomers are currently expanding the search to fainter galaxies. They hope to find more refined constraints on the concept of dark energy within a year or so.
From: New Scientist
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