Astronomers have directly detected an extraordinarily faint radio signal from hydrogen gas billions of light-years away, demonstrating a promising new method for mapping the vast structure of the Universe.
The international team, led by researchers at the University of Manchester and the University of the Western Cape, used South Africa's MeerKAT radio telescope to measure emissions from neutral hydrogen dating to a period when the Universe was several billion years younger than it is today.
Published in The Astrophysical Journal Letters, the results highlight the growing potential of hydrogen intensity mapping, a technique designed to survey enormous regions of space far more efficiently than methods that rely on identifying galaxies individually.
Mapping the Universe With Hydrogen
Neutral hydrogen naturally gives off a very weak radio emission known as the 21-centimeter line. Because the Universe is expanding, this signal becomes stretched to longer wavelengths as it travels through space. By measuring that shift, astronomers can study hydrogen from different eras in cosmic history.
