As often happens in science, this paper from Aiola comes at the same time as competing research, looking at that expansion rate from the perspective of galaxies, and that new research is more than we could consume in time to thoroughly prepare for today’s show. This is because the extended Baryon Oscillation Spectroscopic Survey (eBOSS) team has released dozens of papers that combine to more than 500 pages of observations and analysis of galaxies across 11 billion years of the universe’s evolution. Using data from the Sloan Digital Sky Survey, they find, once again, this time not using the CMB, that the expansion rate in the early universe is about ten percent lower than the value found from the distances to nearby galaxies. According to team researcher Eva-Maria Mueller: Only with maps like ours can you actually say for sure that there is a mismatch in the Hubble Constant. These newest maps from eBOSS show it more clearly than ever before.

As is pointed out in the press release: There is no broadly accepted explanation for this discrepancy in measured expansion rates, but one exciting possibility is that a previously unknown form of matter or energy from the early Universe might have left a trace on our history.

This is a tremendous result, and I’m going to be digging into these papers in the coming days. Prior to this moment, we had two data sets, one for the early universe that showed an older universe and slower expansion and one for the current universe that showed a younger universe with faster expansion. Now, we have data spanning these two epochs that makes it clear the universe’s behavior changed over time. 

I no longer know exactly how old the universe is. Somewhere between 13.5 and 14 billion is guaranteed, I think, but everything else is a bit of an uncomfortable mess, and this is a lot to take in on a Monday morning.

More Information

SDSS press release 

Carnegie Science press release 

University of Portsmouth press release