We have one more study showing that the modern universe is expanding at 73-75 kilometers per second per megaparsec, a number that doesn’t agree with what is happening in the early universe. Ever since this discrepancy was discovered, folks have been trying to find either an error in the observations or some other factor that would bring the different sets of measurements into an agreement. The problem is, every different way we have found to measure things in the modern universe keeps matching. Supernovae results match lensing results, match – we learn now – the results of considering the average scatter in the brightness of stars in elliptical galaxies. 

In a new paper in The Astrophysical Journal, a team led by John Blakeslee looks at 63 of the hundred most massive galaxies within 100 megaparsecs of our galaxy. These systems should have similar stellar populations, and closer systems will have greater pixel-to-pixel variations; essentially, we can clearly see their texture. Farther systems will appear smoother, as more stars blur together in each pixel. 

Using these pixel-to-pixel variations, the team determined the distance to each galaxy. They also separately measured how fast each galaxy is being carried away from us by the expansion of the universe. Combining all this data and comparing it with other measurements, everything still matches, and we are no closer to understanding why the expansion rate of the universe is different when you look at different times in the universe.

It is all a kind of a hot mess; literally, the universe is hot, and it is messy. 

More Information

UC Berkeley press release

“The Hubble Constant from Infrared Surface Brightness Fluctuation Distances,” John P. Blakeslee et al., to be published in The Astrophysical Journal (preprint on arxiv.org)