Astronomers use radio to glimpse early stars
February 28, 2018
A team of scientists from the Arizona State University (ASU) School of Earth and Space exploration used a table-sized radio spectrometer at the CSIRO Australian national science agency's observatory in the desert where they could escape radio interference.
"Telescopes cannot see far enough to directly image such ancient stars, but we've seen when they turned on" — that is, sparked to life — "in radio waves arriving from space," ASU astronomer and the project's lead investigator, Judd Bowman, said. The research is based on changes in the wavelengths produced by radio signals.
"It's a time of the universe we really don't know anything about," Bowman said, describing the discovery as being "like the first sentence" in an early chapter of the history of the cosmos.
Fingerprints of the stars, already active 13.6 billion years ago, were picked up by the small radio spectrometer.
"Finding this miniscule signal has opened a new window on the early universe," Bowman added. The signals suggest the first stars were born just 180 million years after the universe began.
Scientists believe that for about 400,000 years after the Big Bang, the Universe was dark — filled primarily with hydrogen. Gravity slowly pulled the densest regions of gas together to form stars, according to the ASU researchers. The signals detected in the radio study came from primordial hydrogen, at a time that light from the first stars made the gas detectible for the first time.
"The apparent detection of the signature of the first stars in the Universe will be a revolutionary discovery if it stands the tests of time," Nobel Prize-awarded astrophysicist Brian Schmidt of The Australian National University said about the findings, which have been published in Nature magazine.
jm/sms (AFP)