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The SDSS-III collaboration

A still image from the 3D map of the universe released by the SDSS-III.

Largest ever 3D map of the universe released

by Joanna Carver
Aug 22, 2012

Seeing the universe in 3D just got easier—and a lot more amazing.


The Sloan Digital Sky Survey III, an astronomical survey based from a 2.5 meter-wide telescope in Mexico, released the largest ever 3D map of the universe this month.


With it come measurements of the some 500 million stars and galaxies, available at the SDSS website. But the mapping also may give fundamental clues to better understand forces we can’t see within two of the last big mysteries of astronomy: dark matter and dark energy.


“The primary goal now is dark energy and specifically the history of dark energy as a function of time,” said David Schlegel, one of SDSS’s principal investigators. “There is a feature in the large-scale structure in galaxies that has an imprint from the beginning of the universe” and may finally reveal the dark forces.

As astronomers look further toward the edge of the universe, they are actually looking back in time, because the light is traveling such a massive distance to reach them.


“We’re actually probing back to the young eras of the universe,” Wood-Vasey said. “The existence of dark matter and dark energy means there’s something fundamental we’re missing in our description of physics. Understanding that will change the next generation’s whole perspective on particle physics.”


Dark matter and dark energy comprise about 96 percent of the universe, but is invisible to scientists because it doesn’t interact with light. Luckily, it does interact with gravity and it can be detected through gravitational measurements.


Dark energy is believe to be the force responsible for the universe expanding at an accelerating pace while dark matter is theorized to provide the extra gravity needed to hold the galaxies together.


“It clumps, it sort of attracts itself,” said Michael Wood-Vasey, spokesman for SDSS-III. “Understanding how this process happens is a function of age in the universe. In making these maps of millions of galaxies, we can figure out how they’re distributed and how the dark matter is distributed.”


Sloan released a 2D map of the universe last year, but Wood-Vasey said that the new map shows a 40 percent increase in data, giving a wider, more complete view of the visible universe.


“It’s still only a small fraction of the entire visible universe,” he said.


Schlegel said the most exciting aspects of the project are still to come. He hopes the data from the maps will agree with the simplest theories for the existence of dark matter.


“What we do know is that we’re making the best measurements we can make,” he said.