Something like 68% of the universe is made up of dark energy, a mysterious force thought to fuel the expansion of the universe. Another 27% is dark matter, which – as CERN explains – “does not absorb, reflect or emit light,” even though it seems to pull at the things in the universe we can actually see.

But there’s still a lot we don’t know.

To more precisely measure the effects of dark energy, a research group comprised of hundreds of physicists and astronomers has created what they describe as the “largest-ever, three-dimensional map of distant galaxies.”

You can see one slice through the map below:

This image shows the positions of 48,741 galaxies about 6 billion years into the past and covers about 1/20th of the sky, showing a slice of the universe that’s 6 billion light-years wide and 4.5 billion light-years high. (Each dot is a galaxy.)

It indicates depth too, by using color (yellow is nearer to Earth and purple is further), making the slice 500 million light-years “thick.” The way that galaxies cluster together into what are known as superclusters helps show the structure of the universe and the attractive force of gravity.

Still, that image just shows about 3% of what the full survey by the Sloan Digital Sky Survey III (SDSS-III) mapped – their full map includes 1.2 million galaxies.

“We’ve made the largest map for studying the 95% of the universe that is dark,” David Schlegel, an astrophysicist at Lawrence Berkeley National Laboratory (Berkeley Lab), said in a press release. Schlegel is the principal investigator for the Baryon Oscillation Spectroscopic Survey that created the map. “In this map, we can see galaxies being gravitationally pulled towards other galaxies by dark matter. And on much larger scales, we see the effect of dark energy ripping the universe apart.”

The group has submitted a collection of papers describing their results to the journal Monthly Notices of the Royal Astronomical Society.

The map itself was made by measuring the effects of pressure waves that traveled across the universe when it was just 400,000 years old, more than 13 billion years ago.

In the image below, you can see how a slice of 10% of the map could be expanded to show the three-dimensional structure of the universe, with voids of nothingness and bright superclusters of galaxies.

We can now measure how much the galaxies and stars cluster together as a function of time to such an accuracy we can test General Relativity at cosmological scales,” Shirley Ho, an astrophysicist at Berkeley Lab and Carnegie Mellon University, said in a press release.
The researchers say that so far, the data seems to support the standard cosmological model of the universe.
In the future, these results will allow researchers to even further show the effects of dark energy and could reveal what Natalie Roe, Physics Division director at Berkeley Lab, describes as “ultimately the future of our universe.”