Astronomers detect light from first-ever stars in pioneering discovery

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But researchers had never had the evidence to back it up until now.

"This is really the only possible probe that we have of the time before the stars", says Bowman, who is an experimental astrophysicist at Arizona State University in Tempe.

These very ancient stars were trailblazers.

According to the astronomers, the future Square Kilometre Array will tell more about the early days of the Universe as it is able to in-depth measure of the signals coming from any part of the sky.

To everyone's surprise, and delight, the signal contained something curious.

Physicists believed that our universe was dark, hot and full of high-energy particles.

The scientists used a simple radio antenna - similar in size to a tabletop, coupled with an exquisitely sensitive receiver to see further back than even the Hubble telescope. For starters, there are fewer and fewer stars to find.

The earliest star lights, astronomers theorized, would have heated up the hydrogen gas permeating the universe, which would be reflected in the cosmic microwave background.

Acknowledging this difficulty, many years ago the CSIRO began building the Murchison Radio-astronomy Observatory (MRO) in the centre of Western Australia.

This research was supported by funding from the National Science Foundation. "It is like being in the middle of a hurricane and trying to hear the flap of a hummingbird's wing".

Now, 13 billion years later, that shadow would be expected at a much lower frequency because the universe has expanded almost 18-fold in that time. Hydrogen emits and absorbs radiation at a wavelength equivalent to 1,420 megahertz, so the signal EDGES detected had been "redshifted"-stretched to lower frequencies by the expansion of the universe".

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Eventually stars formed and over hundreds of millions of years, galaxies.

"Finding this minuscule signal has opened a new window on the early universe", lead author Judd Bowman of Arizona State University told The Guardian. After 370,000 years, this soup began to form neutral hydrogen atoms.

"There are only two ways an absorption signal against background radiation could be stronger than expected".

Bowman said he'd welcome such efforts. Barkana, Head of the Department of Astrophysics at the Tel Aviv University, who published the paper detailing the link between this signal and dark matter.

Scientists have known dark matter exists, indirectly, through measurements based on gravity.

Certain characteristics in the detected radio waves also suggest that hydrogen gas, and the universe as a whole, must have been twice as cold as scientists previously estimated, with a temperature of about 3 kelvins, or -454 degrees Fahrenheit. Thus, the dark matter and the matter interacted, which is contrary to what we can observe now when these two types of matter are not interacting anymore.

"If Barkana's idea is confirmed", says Bowman, "then we've learned something new and fundamental about the mysterious dark matter that makes up 85 percent of the matter in the universe, providing the first glimpse of physics beyond the standard model". "When you're driving in the auto, you don't want to be changing the station all the time", Bowman said. Luckily for us, one such array, the SKA, the largest telescope in the world, is already under construction - if it picks up on the signal, the SKA "would confirm that the first stars indeed revealed dark matter", concludes Prof.

"These results require some changes in our current understanding of the early evolution of the universe", says Colin Lonsdale, director of Haystack Observatory.

The signal dip was very different than the researchers anticipated. But now that astronomers know where and how to look, others will confirm this and learn more, Bowman said. We know its there because we can measure its gravitational effect, but that's about it.

While no telescope today can detect the glow from these first stars, theory suggests that the ultraviolet radiation from them could have possibly pierced the hydrogenous haze of the primitive universe - leading to exciting its atoms.

"What we've seen is the evidence of the first hydrogen at a point where the stars are just beginning, the very early stars", says Alan Rogers, a researcher at MIT's Haystack Observatory.

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