The “Hubble voltage”It is one of the greatest enigmas of contemporary cosmology. It refers to the fact that the increasingly precise measurements of the speed at which the universe disagrees expands. And not We have a lot of idea of why.
Faster Now a new study has led Hubble tension to a new maximum. The work indicates that the observed acceleration of the universe is greater than what today’s physical models could explain.
Theory and practice. There are two forms of measure the expansion of the universe. The first is based on the cosmic microwave background (CMB), a remaining radiation of the process that we know as big Bang. By measuring fluctuations in this background, it is obtained An estimate of the expansion speed of about 67 kilometers per second by Megaparsec (km/s/mpc), an expansion speed according to what the generally accepted cosmological models estimate.
On the other hand, observations of the nearest universe tell another story. The cefaids are stars whose brightness is inversely related to the frequency with which they press.
This allowed astronomers to create a “cosmic ladder” calibrating step to step the measurements of distances to increasingly distant objects in the cosmos. The problem is that this other measure estimates a significantly higher expansion speed: about 74 km/s/mpc.
From tension to the crisis. The new study has deepened this discrepancy. The new measure based on the “cosmic ladder” has estimated an expansion rate even greater than the average of the previous measurements: about 76.5 km/s/mpc. This has led the team to point out that “The tension has become a crisis.”
The step that was missing. The team responsible for the study created its own “cosmic ladder” from the DESI collaboration data (Dark Energy Spectroscopic Instrument). This instrument monitor about 100,000 distant galaxies thanks to 5,000 robots with fiber optic sensors that monitor space.
The team responsible for the study had to “anchor” these data to our immediate vicinity, that is, put the first step of the “cosmic ladder” with which to measure the changes observed by DESI in its follow -up of these galaxies. To do this, he resorted to the cluster of the comma, one of the galactic clusters closest to the Milky Way.
Supernovas To measure the distance to this cluster, the team turned to the light curves of 12 IA type supernovae located within your own Cluster. This type of supernovas shines in a very predictable way, so its apparent brightness gives us a good measure of its real distance.
The details of the process can be consulted In an article Posted in the magazine The Astrophysical Journal Letters.
The search continues. These types of intrigues generate great interest in the scientific community since it is through cracks in ancient models that are usually opened by the discovery of new theories. “It’s exciting,” explain those responsible for the study. But the truth is that, for now, we have few clues that allow us to solve this issue, either through substantial changes in contemporary models, either through changes in the paradigm.
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Image | NASA, ESA, Hubble Heritage Team (STSCI/Aura)D. Carter (Liverpool John Moores University) and Coma HST ACS Treasury Team.