The Hubble constant discrepancy has passed a milestone

Is renormalization the answer?

Credits: NASA, ESA, A. Riess (STScI/JHU) and Palomar Digitized Sky Survey

The Hubble tension controversy is a measurement discrepancy of the Hubble constant. This constant is the rate at which the universe is expanding. It is measured in kilometers per second per Megaparsec because the farther two galaxies are from one another, the faster they move apart.

The Hubble constant is measured in two ways: (1) by observations of distant Supernovae that we can see both electromagnetically and, more recently, with gravitational wave detection and (2) by looking at the Cosmic Microwave Background (CMB), the echo of the formation of the universe and the earliest light we can see.

Credits: NASA, ESA and A. Feild (STScI)

A great deal of progress has been made on both fronts in recent years which has led to the Hubble tension controversy. The value for the Hubble constant measured by observations of distant galaxies is 73.04 +/- 1.04 km/s/Mpc. The value for the CMB, as measured by the Planck spacecraft in 2018, is 67.36 +/- 0.54.

Thanks to improved statistical techniques and measurements correlating electromagnetic imaging with gravitational wave detection, the SH0ES experiment has…