Astronomers May Have Found the Universe'

Astronomers May Have Found the Universe’s First Stars!

February 28, 2018

By Lora Snow

Astronomers may have found the Universe’s first stars. There is now evidence that stars existed by around 180 million years after the Big Bang, which is estimated to have occurred about 13.8 billion years ago.

The astronomers did not find these stars with a telescope. Instead, they used a radio antenna about the size of a kitchen table. The project was called Experiment to Detect the Global EoR (Epoch of Reionization) Signature (EDGES).

Video: NSF's Peter Kurczynski on how scientists

detected a signal from the birth of the first stars. Credit: NSF

They conducted their experiment at the Murchison Radio-astronomy Observatory (MRO) in Western Australia. This location is an extraordinarily radio quiet area controlled by the Commonwealth Scientific and Industrial Research Organization, Australia’s national science agency.

Conducting the experiment in a radio quiet area was important because the radio signal the team was looking for overlapped with frequencies on the FM radio dial. Also, our own Milky Way Galaxy produces radio signals.

Stars trigger radio signals when their light interacts with hydrogen gas in space. This frequency, when created, would have been about 1420 megahertz. The signal EDGES found was about 78 megahertz, however.

Higher frequency waves have shorter wave lengths. The radio waves produced by these first stars have been traveling through space for so long that they had stretched dramatically. That’s how astronomers were able to identify the stars and estimate that they were shining about 180 million years after the Big Bang.

A timeline of the universe, updated to show when the first stars emerged.

Credit: N.R.Fuller, National Science Foundation

Coauthor of the study, Judd Bowman of Arizona State University, said the signal was actually stronger than their team expected it to be. This may mean the universe was colder at that time than they anticipated, and it may also mean that dark matter is involved.

Bowman and his team spent about two years conducting tests in order to rule out errors, even ruling out interference from the sun and moon. Their findings were robust.

Other groups are working to confirm their test results. The Hydrogen Epoch of Reionization Array in South Africa’s Karoo desert, for example, is being adapted to detect the stars signals.

And the Low-Frequency Array (LOFAR), a system of antennas across Europe, may be able to map how the signal fluctuates across the sky and may reveal more about whether or not dark matter is involved.

The study, which was funded by the U.S. National Science Foundation, was published on February 28, 2018 in the journal Nature.

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