Another piece of the puzzle of the universe’s creation has been discovered. A small radio antenna in Western Australia recently detected faint traces of hydrogen gas from 180 million years after the Big Bang, MIT researchers said.
It was not only the earliest detection of hydrogen in the universe but it also appeared to support the notion that the first stars lit up around that time, a cosmic dawn that moved the universe out of darkness, said Alan Rogers, the study’s coauthor and a scientist at MIT’s Haystack Observatory.
The findings, by astronomers from the Massachusetts Institute of Technology and Arizona State University, were published in the journal Nature Wednesday
The astronomers believe that stars were created by gravitational collapses and fusion of hydrogen atoms, Rogers said.
“Stars form when gas — mostly hydrogen — has cooled and becomes subject to fluctuations, and pieces of it start to collapse,” he said. “Once you get that collapse, you get the internal heating and nuclear reactions start to light it up.”
The stars then emit ultraviolet radiation and surrounding hydrogen atoms absorb it — a phenomenon the researchers were able to detect through radio waves, he said.
“As the universe expanded over time, this radiation became ‘red-shifted’ to lower frequencies,” MIT said in a statement.
Once the radiation reached Earth, it landed somewhere in the range of 100 megahertz.
“It’s a very early marker in the evolution of the universe,” Rogers said.
The radio antenna, an instrument about the size of a small table, detects radio waves from the sky, Rogers said. When researchers saw a dip in the spectrum as they zeroed in at 70 megahertz, they were surprised.
The dip suggested that the hydrogen was about twice as cold as scientists originally thought — about 3 Kelvins, or minus 454 degrees Fahrenheit — said Colin Lonsdale, director of the Haystack Observatory.
“That’s very significant,” he said. “The theoretical community has developed quite sophisticated models of how the universe developed, and they predicted about how cold it should be. They expected it to be warmer than that.”
The next step for Rogers and his team is to reach out to other research groups around the world to confirm and build upon what they uncovered, Rogers said. Adjusting the antenna to different frequencies and sending out new satellites are also on the agenda, he said.
“These results are profound,” Lonsdale said. “This is a very fundamental measurement about the nature of the universe. The early history of the universe is something that has been one of the Holy Grails of astronomy for decades.”