SCIENTISTS HAVE PICKED UP SIGNALS FROM THE FIRST EVER STARS:
WHAT DID THE SCIENTISTS DISCOVER?
Using a small radio telescope at the CSIRO's Murchison Radio-astronomy Observatory, 600km northeast of Perth, they picked up faint radio wave signals from when the first stars formed about 180 million years after the Big Bang. The discovery indicates the end of the "Dark Ages" when there were no stars, galaxies or planets. Astronomers have never before observed this period in the universe's history. The team of scientists was led by Arizona State University astronomer Dr Judd Bowman.
WHAT WAS THE BIG BANG?
Astronomers believe the universe started at a single point about 13.8 billion years ago. Back then it was just hot, tiny particles mixed with light and energy. Then the universe began expanding and cooling, with the tiny particles forming atoms that grouped to form stars and galaxies.
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WHY IS THE DISCOVERY IMPORTANT?
Scientists have long puzzled over when the Dark Ages ended. The signals the researchers picked up indicate it happened 180 million years after the Big Bang. Peter Kurczynski, program director at America's National Science Foundation, says if the age of the universe was mapped into a single 24-hour day, it's like finding out what happened 15-20 minutes after the Big Bang.
HOW HARD IT WAS TO DETECT THE SIGNALS FROM THE FIRST STARS?
The world doesn't have a telescope powerful enough to see the first stars, so scientists have tried to find indirect evidence of them. Dr Bowman and his team spent more than a decade fine tuning their antenna to measure radio waves coming from space.
The antenna acts like a car radio but instead of tuning into music it measures how bright the sky is at different frequencies.
While tuned into a low frequency, the antenna picked up a dip in the intensity of radio waves from space. The scientists believe that dip was caused by a cooling in the hydrogen gas swirling through the universe in reaction to the first stars "turning on". They pinpointed that time to 180 million years after the Big Bang.
WHY WAS THE ANTENNA IN SUCH A REMOTE SPOT?
The CSIRO's Murchison Radio-astronomy Observatory sits in a 260km "radio quiet" zone, which ensures that there is minimal interference from man-made devices like mobile phones while astronomers try to detect signals from space. The CSIRO considers the site sets the "gold standard" in radio quietness.
DARK MATTER
The discovery may provide insights into the mysterious dark matter making up most of the universe. The cooling by the hydrogen gas in reaction to the first stars lighting up happened at a lower temperature than expected, suggesting dark matter may have had some effect.
WHAT'S NEXT?
Dr Bowman and his team spent two years validating their discovery and hope an independent group can confirm their findings. He hopes it accelerates the development of new radio telescopes that can mine the signals coming from the first stars for more information.
