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'Crisis' because scientists admit they don't really know how fast the universe is developing

The universe is expanding faster than scientists think, potentially rewriting our universe model.

For years, researchers have debated how fast the cosmos is growing. Measurements were repeatedly carried out with different answers, confusing the researchers who took them.

Now the latest measurements once again show that our understanding of the expansion of the universe is wrong. This uses a new method to prove that speed – known as the Hubble constant – may be even more unusual than we thought.

Astronomers keep the results of research even secret from themselves during the study, to ensure that they will not be affected by how strange their measurements can prove.

To understand the extent of the expansion of the universe, astronomers led by the University of California, Davis used NASA's Hubble Space Telescope along with technology on land. This is the first time the last piece of equipment – the Adaptive Optics (AO) WM Keck Observatory system – has been used to measure the Hubble constant.

"When I started dealing with this problem more than 20 years ago, the available instrumentation limited the amount of useful data that you could get from observations," said co-author Chris Fassnacht, Professor of Physics at UC Davis. "In this project, we are using the AO Keck Observatory for the first time in full analysis. I have felt over the years that AO's observations can contribute a lot to this effort. "

The results have been published in the latest issue of Monthly Notifications from the Royal Astronomical Society.

To ensure that the results are reliable, the researchers went to the research blind: ensuring that they kept the final conclusions hidden while they worked to ensure their measurements were as accurate as possible. That means that researchers can avoid the worry that they will unconsciously adjust the findings to ensure that they are in line with expectations.

"When we think that we have taken care of all the problems that might occur with analysis, we open the answer with the rule that we must publish whatever value we find, even if it's crazy. It's always a tense and exciting moment," said the lead author , Geoff Chen, a graduate student in the UC Davis Department of Physics.

When they finally saw the results, they found that the numbers showed the universe was expanding faster than they thought.

That in turn can complicate our understanding of the universe under a standard cosmological model. Researchers generally think that the expansion of the universe was very fast when it first formed, then slowed when dark matter pulled it, and now it is getting faster because of dark energy.

It was created by looking at very distant objects, looking at the background of cosmic microwaves or radiation left over from the Big Bang when it started the universe.

But the new study looks at more local objects. A number of studies have found that there is an unexplained difference between the measured velocity of local objects and the results found when examining distant ones.

"Therein lies the crisis in cosmology," Fassnacht said. "While the Hubble Constant is constant everywhere in space at any given time, it is not constant in time. So, when we compare the Hubble Constants that come out of various techniques, we compare the early universe (using distant observations) vs. the more modern end of the universe (using local, closest observations). "

That shows that there is a problem with our understanding of the cosmic microwave background – which according to researchers is impossible – or that there is something profoundly and fundamentally wrong with our understanding of physics.

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