What is the value of cosmology

Cosmology in CrisisThe return of the Hubble constant

For about two decades, some astronomers have been thinking that we are living in the era of precision cosmology: Because the values ​​in the formulas for describing the world can be determined to several decimal places. But that shows some arrogance for two reasons.

On the one hand, it would only be real precision if today's models actually corresponded to reality. On the other hand, even the supposed precision cosmology cannot explain what 95 percent of the universe is made of: Dark matter and dark energy are very precise, completely puzzling to this day.

There are now a number of observations that pose great problems for cosmologists. It is all about the Hubble constant: It indicates how quickly the universe is expanding and was the subject of heated debates until 30 years ago.

Then, among other things, a team from the Hubble space telescope had determined a very precise value - so it was believed. The dispute seemed to be settled. But time and again, the value of the Hubble constant, measured with the help of galaxies in space, turns out to be around ten percent higher than that resulting from the analysis of the cosmic background radiation.

Something seems to be wrong: either our area of ​​the universe is moving unusually fast. Or the world models are not quite as precise as some believe. Observation programs are currently running again to determine the Hubble constants. One thing is clear: Somehow the worm is currently in cosmology.