Want to get away? Now you can see how far "away" really is. Drawing on 20 years of research, scientists have created a 3D map of the universe that spans 11 billion years and covers more than 2 million quasars and galaxies—while shedding light on a couple of cosmological mysteries along the way, CNN reports. "We know both the ancient history of the universe and its recent expansion history fairly well, but there's a troublesome gap in the middle 11 billion years," says study leader Kyle Dawson of the University of Utah in a statement. "For five years, we have worked to fill in that gap." Enter the Sloan Digital Sky Survey, an international group of scientists culling data on the universe from various tools and telescopes. Key to this was their measurement of "redshift."
That's the process of light from distant galaxies stretching across the universe and shifting to the red end of the spectrum as it goes—which is why light sources on the map appear bluer when closer to Earth, per LiveScience. Looking at more galaxies and quasars than ever before, scientists measured their redshift and velocities and concluded that the universe's expansion increased roughly 6 billion years ago. Why? Because of dark energy, which remains a mystery. Check out Forbes for more inside baseball on the map, like its controversial conclusion on the universe's rate of expansion (68.2 km/s/Mpc, in case you were wondering). The SDSS "is nowhere near done with its mission to map the universe," the group says, adding that it's "building the hardware" to make "new discoveries of the next 20 years." (Read more astrophysics stories.)