The early stage in the formation of the universe remains largely a mystery to modern science. But in a new study published in the journal Nature, researchers have made a compelling case for when exactly the very first stars began to form. After the Big Bang about 13.7 billion years ago, the universe was dark, hot, and filled with high-energy elementary particles. After 380,000 years, the universe has cooled down enough for photons to exist. It was then that the first cosmic microwave background (CMB) appeared, thanks to which scientists were able to learn more about the origin of the universe.
The researchers suggested that by examining the intensity of the cosmic microwave background, it is possible to establish the moment when the first stars began to form. When stars begin to form, they heat up the hydrogen gas that permeates the universe. As the gas heats up, it absorbs CMB, as a result of which its intensity decreases. It is impossible to detect such deviations using traditional telescopes, but here radio signals come to the aid of science. However, these signals are so weak that they are easily obscured by any noise, which at times can be tens of thousands of times stronger. As one researcher put it, "Looking for such signals is like trying to hear hummingbird wings rustling in the midst of a hurricane."
However, such difficulties did not stop scientists. A team of researchers from the University of Arizona and the Massachusetts Institute of Technology decided to detect early star formation signals, and, as incredible as it sounds, they did it. And they did all this using a relatively small antenna (in the photo just below). The antenna was installed in one of the Australian deserts, since it is in such places that interference from radio signals created by man can be minimized. For the first time, luck smiled at scientists in 2016. It was then that the first drop in the CMB intensity was recorded. According to the data obtained, we can conclude that the first stars formed about 180 million years after the Big Bang.
“This is very exciting, because for the first time we were able to look with at least one eye into the most important period of the formation of our Universe. It was then that the first stars and galaxies began to form. This is the first time that science has received direct observational data from that era,”said Colin Lonsdale, director of the Haystack Observatory.
The research team spent over a year confirming their own conclusions based on the received signals. The position of the antenna was changed, a different calibration of the measuring instruments was used. But at the same time, the signal was observed every time, while it turned out to be twice as intense as originally expected. This proves that hydrogen in the early universe was much colder than previously thought. Researcher Rennan Barkana of Tel Aviv University claims that dark matter may explain the colder universe.
The data obtained as a result of the research must still be confirmed by other experts in the field. Nevertheless, many scientists who have already familiarized themselves with the results of the experiment of specialists from MIT and the University of Arizona believe that this discovery pulls one, or even two Nobel Prizes. The first prize can be awarded to scientists for determining the age of the first stars, and the second - for a discovery related to colder hydrogen and dark matter, which is quite capable of expanding the existing standard physical model. You can read the research results here.
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