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.
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…
I waxed poetic while holding my breath in late 2019, waiting for the star Betelgeuse to go nova. It was dimming in a most-notable manner, which was odd and exciting. Then it brightened again, seeming to thumb its photonic nose at us all.
The mystery of what this red giant was up to seems to be solved. While not as exciting as a supernova, it is pretty nifty. The actual astronomical images are available online, but this artist’s rendering is eye-catching.
Hubble Space Telescope’s UV data… combined with some timely ground observations indicated that a big burp that formed a cloud of dust near the star may have caused the star to get darker.
“With Hubble, we could see the material as it left the star’s surface and moved out through the atmosphere, before the dust formed that caused the star to appear to dim,” said Andrea Dupree, an astronomer at the Harvard-Smithsonian Center for Astrophysics who made those observations. She is also a co-author on the new paper. ARS
It’snew, it’s big, and it’s open to international scientists. We shed tears over the final demise of the Arecibo Observatory, which stood as the largest telescope of its type in the world for 53 years. Now a Chinese observatory, constructed in 2016, steps up.
With its massive 1,600-foot (500 meters) diameter dish, FAST [the new telescope’s acronym] is not only larger than the now-destroyed Arecibo telescope, but it’s also three times more sensitive. FAST, which began full operations in January of this year, is also surrounded by a 3-mile (5 kilometers) “radio silence” zone in which cellphones and computers are not allowed. livescience
China is accepting international proposals now. Yes, astronomers would have preferred to have both observatories, but it’s good to know that studies of black holes, exoplanets, and who-knows what else will continue.