[ad_1]
Who says you can’t get hotter with age?
Researchers from Johns Hopkins University and other institutions have found that, on average, the temperature of galaxy clusters today is 4 million degrees Fahrenheit. This is 10 times hotter than 10 billion years ago and four times hotter than the Sun’s outermost atmosphere called the corona. The results are published in the Astrophysical Journal.
“We have measured temperatures throughout the history of the universe,” said Brice Ménard, professor of physics and astronomy at Johns Hopkins. “As time goes by, all of those galaxy clusters are getting hotter and hotter because their gravity is pulling more and more gas towards them.”
Brice Ménard of Johns Hopkins and Xi-Kuan Chiang of Ohio State University. (Credit: Ron Scheffler)
Yi-Kuan Chiang, lead author of the study who was a postdoctoral researcher at Johns Hopkins until moving to Ohio State University last year, added, “This resistance is so violent that more and more gas is being shocked and heated.”
Imagine all those gas atoms being sucked into galaxies as if they were myriads of meteoroids piercing the Earth’s atmosphere, Ménard said. They accelerate as gravity pulls them towards the Earth’s surface and warm up due to friction with the atmosphere before burning into what are seen as shooting stars, he added. This pattern of warming due to gravitational forces can be applied to entire galaxies, clusters of galaxies and beyond in the “large-scale structures” of the universe formed by gravity – a
theory attributed to James Peebles, Nobel Prize in Physics 2019.
“Our measurements are a great confirmation of this theory,” Ménard said.
To perform this analysis, the team used data collected by the astronomical community over two decades, first from a ground-based telescope that conducted the Sloan Digital Sky Survey and then the Planck mission, a space telescope led by the Space Agency. European.
As the universe evolves, concentrations of matter are surrounded by gas halos that get hotter and hotter. (Credit: D. Nelson / Illustris Collaboration)
The team used a technique that Ménard developed with Chiang. With it, they estimated the “redshift” of gas concentrations seen in microwave light images that go back in time to 10 billion years ago. “Redshift” describes how the wavelengths of light get longer due to the expansion of the universe. The further away something is, the longer its wavelength and the older its origin.
The method allowed them to measure the gradual rise in gas temperature as a function of the age of the universe. This trend is also predicted by numerical simulations that show how dark matter and atoms in the gas evolve over time. As illustrated in the figure, these visualizations show the temperatures of the gas changing from a cold blue canvas of 10 billion years ago to a hot red dotted today.
Warming of the universe has nothing to do with global warming on Earth, Ménard said. It is a consequence of the gravitational pull that was predicted but can now be accurately measured with these new techniques.
Researchers from the University of Tokyo and the Max Planck Institute for Astrophysics contributed to this work, which was supported in part by the NSF grant AST1313302 and NASA NNX16AF64G (YC, BM). Additional support came from the ORIGINS cluster of excellence, funded by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under the German excellence strategy-EXC-2094-390783311 (EK) and the JSPS KAKENHI grant no. JP15H05896 (RM, EK) and JP20K14515 (RM).
.
[ad_2]
Source link
