The analysis of early universe radio signals provides the first direct proof of the existence of dark matter, the ubiquitous yet invisible material making up the universe, Tel Aviv University Professor Rennan Barkana said Wednesday. His statement followed publication of his paper by the prestigious scientific journal Nature this week.
The research followed work by a team led by astronomer Judd Bowman from Arizona State University in Tempe, Arizona, who detected a radio signal dating back to the time the stars and galaxies formed, some 180 million years after the Big Bang.
The radio signal was picked up by the radio telescope EDGES in Australia as part of an effort to date various stars.
Barkana, who heads the Astrophysics Department at Tel Aviv University's School of Physics and Astronomy, realized that they might have stumbled upon the first concrete proof of dark matter, which cannot be observed but is widely believed to be the "universe's building block."
In his paper, Barkana said the length of the radio wave was the key to figuring out when it was generated.
"This was the first signal that we could detect from the very interesting era in which stars and galaxies began to form, some 13.5 billion years ago," he said in a press release following the publication.
"Dark matter is the key to unlocking the mystery of what the universe is made of," he said.
"We know quite a bit about the chemical elements that make up the Earth, the sun and other stars, but most of the matter in the universe is invisible and known as 'dark matter.' The existence of dark matter is inferred from its strong gravity, but we have no idea what kind of substance it is. Hence, dark matter remains one of the greatest mysteries in physics.
"To solve it, we must travel back in time. Astronomers can see back in time, since it takes light time to reach us. We see the sun as it was eight minutes ago, while the immensely distant first stars in the universe appear to us on earth as they were billions of years in the past."
While astronomers still do not know what makes up dark matter, they are fairly confident it comprises more than 80% of the matter in the universe.
"We believe we will be able to detect more radio signals that would indicate its existence," Barkana said.
