When gas expands, it cools. The universe is expanding, so it should be cooling too. So scientists thought. So, dang it, why would it be heating up?
First, what is heat? Especially out in space where there is so-close-to-nothing, we call it empty. Heat is a measure of the energy of whatever particles are under consideration, so even in a near vacuum, there is heat.
According to new research led by the Center for Cosmology and AstroParticle Physics (CCAPP) at Ohio State University, it appears that the Universe is actually getting hotter as time goes on.
After probing the thermal history of the Universe over the last 10 billion years, the team concluded that the mean temperature of cosmic gas has increased more than 10 times and reached about 2.2 million K (~2.2 °C; 4 million °F) today.
As the Universe evolves, gravity pulls dark matter and gas in space together into galaxies and clusters of galaxies. The drag is violent – so violent that more and more gas is shocked and heated up.” Science Alert
Collecting data from 10 billion years ago sounds like quite a trick, but keep in mind that light from sufficiently distant locations has been traveling for a really long time, and astronomers routinely study objects that are a really long way away, right back to the Big Bang.
It’s fun to see a science article quote poetry:
“Some say the world will end in fire, others say in ice.” Which of these will prove to be correct, and what implications it could have for life in the future, only time will tell…