Radio signals suggest that stars formed only 180 million years after the Big Bang
After years of efforts, astronomers have detected fingerprints of the earliest stars in the universe. They represent a time when light began to spread in the dark universe. The glimpse at early stars could also provide more insight into the dark matter that makes up much of the universe.
The universe was dark and cold for millions of years after the Big Bang. At the time, it was filled primarily with neutral hydrogen gas. Gravity slowly pulled the densest regions of gas together until they collapsed and formed the first stars of the universe. Those stars lit up the early universe, a moment what scientists call “cosmic dawn.”
For years, scientists have been chasing the traces of those stars. Now, they have managed to track the light that was possibly emitted from the earliest stars in the universe. Researchers have detected radio waves from early universe by using a small radio antenna. Those signals suggest that stars began to shine about 180 million years after the formation of universe.
“This is the first time we’ve seen any signal from this early in the Universe, aside from the afterglow of the Big Bang.” Lead researcher Judd Bowman from Arizona State University in Tempe said in a statement.
The radio signals came from primordial hydrogen gas that filled the early universe and were triggered when the gas interacted with dark matter particles. The evidence also hints that the gas in early Universe was colder than predicted.
Since radio waves from early universe are typically faint and hard to detect, researchers chose a remote spot in the Western Australian desert to set up equipment.
“There was a great technical challenge to making this detection, as sources of noise can be a thousand times brighter than the signal – it’s like being in the middle of a hurricane and trying to hear the flap of a hummingbird’s wing.” saidPeter Kurczynski from National Science Foundation program. “These researchers with a small radio antenna in the desert have seen farther than the most powerful space telescopes, opening a new window on the early universe.”
The discovery is being hailed as the most important astronomical breakthrough since the detection of gravitational waves in 2015.
“It is unlikely that we’ll be able to see any earlier into the history of stars in our lifetimes,” said Bowman. “This project shows that a promising new technique can work and has paved the way for decades of new astrophysical discoveries.”