The tremendous 3D map depicts 11 billion years of cosmic history and sets the minor barriers created in our ever-expanding universe. Taken by the Sloan Digital Sky Survey (SDSS), it reinforces our leading picture of the cosmos, though it deepens one enduring mystery.
Light travels at a relative speed, so looking at the sky means looking back at the time. This new survey looks deep enough to identify 80 percent of the world’s 14 billion-year history. “There is no such thing as an integral part of the human race, and it allows us to fill this 11 billion-year gap between the ancient and modern universe,” says Kyle Dawson of the University of Utah. He heads the Baryon Oscillation Spectroscopic Survey. (eBOSS) team in SDSS.
The team looked at galaxies and quasars, prominent centers of other galaxies. It used their redshifts – changes in light because they came from far away – to measure distances and levels and the universe’s expansion. This allows us to look at larger structures such as constructive galaxy collections.
“The whole universe is now in a state of disrepair: there may be objects as huge as galaxies or planets in one place or nothing in another,” said Scott Dodelson of Carnegie Mellon University in Pennsylvania. This was not always the case. “It used to be that if you went to just one place and counted 1000 atoms and went to another random location, you could count 1001 but not even 1002.
Our best way to understand how the universe went from being one to clumpy is a model called lambda-CDM. Some previous estimates have shown that what we see in the universe may not be the same as predictions for that model, but the boss map shows no conflict. So the Lambda-CDM holds up well.
The development of a large structure partly depends on the behavior of particles known as neutrinos throughout the original universe; EBOSS has been able to suppress their weight, which is a significant problem in physics. It did not disappoint, but the estimate was as accurate as of the best neutrino-based test.
The team also forced the atmosphere 10 times stronger than our next best viewing set. As predicted by lambda-CDM, the total space-time seems flat, not curved.
However, the only conflict that exists has been exacerbated by the survey. “Things come together pretty well, except for the Hubble constant,” said Wendy Freedman of the University of Chicago. This is a measure of the rate of global expansion. Our two main calculation methods – using the old cosmic microwave component (CMB) against the local dimensions of nearby objects – are not always consistent.
The eBOSS study complies with the CMB approach, which deepens the puzzle. “Maybe there’s a physics that isn’t somewhere, but no one has been able to come up with it,” Freedman said.