In the last 10 billion years, the universe has not stopped heating up , according to research published in the Astrophysical Journal. It has already reached the average temperature of around 2 million Kelvin, roughly 4 million degrees Fahrenheit. It has been discovered by scientists at the University of Tokyo and Ohio State University who have observed that the average temperature of gases in the universe has multiplied by ten during all those years.
“Our new measurement provides direct confirmation of the seminal work of Jim Peebles, the 2019 Nobel Laureate in Physics, who laid out the theory of how large-scale structure forms in the universe, ” says Yi-Kuan Chiang, lead author of the study. .
The large-scale structure of the universe refers to the global patterns of galaxies and galaxy clusters at 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 to form galaxies and galaxy clusters,” Chiang said. “The drag is violent, so violent that more and more gas is discharged and heated.”
Gas atoms are sucked into galaxies like myriads of meteoroids piercing Earth’s atmosphere. They accelerate as gravity pulls them toward Earth’s surface and heat up due to friction with the atmosphere before burning up into what look like shooting stars. This heating pattern can be applied to entire galaxies and large-scale structures in the universe formed by gravity.
Thus, dragging all this to new stars and galaxies gives heat to all the particles that surround them.
Inquiring the temperature of the universe
To discover the change in temperature, the scientists used data collected by the astronomical community over two decades, from the Sloan Digital Sky Survey and from ESA’s Planck mission. They measured the heat of the gases based on how far they were from Earth. Because light from distant stars and galaxies takes time to reach us, looking at distant objects is also like looking back in time. The further away something is, the longer its wavelength and the older its origin. And the further they looked, the more temperatures seemed to drop, indicating that the cosmos has become warmer over time.
This method allowed them to measure the gradual increase in gas temperature as a function of the age of the universe. The gases in today’s universe reach temperatures of around 2 million Kelvin; about 10 times the temperature of gases around objects further away and further back in time.
Is it related to Earth’s climate change?
No way. “The universe is heating up due to the natural process of formation of galaxies and structures,” said Chiang. “It is not related to global warming. These phenomena are occurring on very different scales. They are not connected at all. “
“As time passes, all these galaxy clusters get hotter and hotter because their gravity draws more and more gas towards them,” concludes the expert.
Referencia: Yi-Kuan Chiang et al. 2020. The Cosmic Thermal History Probed by Sunyaev-Zeldovich Effect Tomography. ApJ 902, 56; doi: 10.3847/1538-4357/abb403
