The universe is getting hot, hot, hot, a new study suggests

The universe is getting hotter, a new study has discovered.

The study, published Oct.13 in the Astrophysical Journal, probed the thermal history of the universe over the past 10 billion years. He found that the average gas temperature in the universe increased more than 10 times over that time period and reached about 2 million degrees Kelvin today, about 4 million degrees Fahrenheit.

“Our new measurement provides direct confirmation of the seminal work of Jim Peebles – the 2019 Nobel Prize in Physics – who exposed the theory of how large-scale structure is formed in the universe,” said Yi-Kuan Chiang. lead author of the study and a researcher at the Ohio State University Center for Cosmology and AstroParticle Physics.

The large-scale structure of the universe refers to the global models of galaxies and clusters of galaxies on scales beyond individual galaxies. It is formed by the gravitational collapse of dark matter and gas.

“As the universe evolves, gravity pulls dark matter and gas into space together into galaxies and clusters of galaxies,” Chiang said. “The resistance is violent, so violent that more and more gasoline is shocked and heated.”

The results, Chiang said, showed scientists how to control the progress of cosmic structure formation by “controlling the temperature” of the universe.

The researchers used a new method that allowed them to estimate the temperature of the gas furthest from Earth – which means further back in time – and compare them to gases closest to Earth and closest to present time. Now, he said, the researchers have confirmed that the universe is overheating over time due to the gravitational collapse of the cosmic structure and warming will likely continue.

To understand how the temperature of the universe has changed over time, the researchers used data on light in space collected from two missions, Planck and Sloan Digital Sky Survey. Planck is the mission of the European Space Agency which operates with the strong involvement of NASA; Sloan collects detailed images and light spectra from the universe.

They combined data from the two missions and evaluated the distances of near and far hot gases by measuring redshift, a notion that astrophysicists use to estimate the cosmic age at which distant objects are observed. (“Redshift” gets its name from the way the wavelengths of light lengthen. The farther away something is in the universe, the longer its wavelength of light. Scientists who study the cosmos call this lengthening the effect of redshift.)

The redshift concept works because the light we see from objects farther from Earth is older than the light we see from objects closer to Earth – light from distant objects has traveled a longer journey to reach us. This fact, together with a method for estimating the temperature from light, allowed the researchers to measure the average temperature of gases in the early universe – the gases surrounding the most distant objects – and compare that average with the average temperature of the most distant gases. close to Earth – gas today.

Those gases in today’s universe, the researchers found, reach temperatures of around 2 million degrees Kelvin, around 4 million degrees Fahrenheit, around objects closest to Earth. This is about 10 times the temperature of the gases around the farthest and furthest objects back in time.

The universe, Chiang said, is warming due to the natural process of galaxy formation and structure. It is not related to warming on Earth. “These phenomena are happening on very different scales,” he said. “They are not connected at all.”

This study was completed in collaboration with researchers from the Kavli Institute for the Physics and Mathematics of the Universe, Johns Hopkins University, and the Max Planck Institute for Astrophysics.