Catching a radio signal 9 billion light-years from Earth

Capturing radio signals 9 billion light-years from Earth - Photo 1.

This radio signal helps scientists investigate the formation of some of the earliest stars and galaxies – Photo: NASA, ESA, CSA, STScI

Radio signals are detected from a single wavelength known as the “21cm line” or “hydrogen line”. This wavelength is emitted from neutral hydrogen atoms.

This signal was received by the Giant Metrewave Radio Telescope in India. This makes it possible for scientists to investigate the formation of some of the earliest stars and galaxies.

The researchers detected radio signals from a “star-forming galaxy” with the designation SDSSJ0826+5630. The signal was emitted when the galaxy was only 4.9 billion years old. Currently, this galaxy is 13.8 billion years old and is where Earth resides.

“It’s the equivalent of looking back in time 8.8 billion years,” said lead author Dr Arnab Chakraborty and cosmologist at McGill University’s department of physics.

Galaxies emit light over a wide range of radio wavelengths. But until recently, only radio waves with a wavelength of 21cm had recorded signals from nearby galaxies.

“A galaxy emits different types of radio signals,” said Mr. Chakraborty. “So far, this particular signal has only been picked up from a nearby galaxy. This provides our understanding of what we know about the radio spectrum,” said Chakraborty. galaxies closer to Earth”.

The signal allows astronomers to measure the gas content of the galaxy, from which they can work out the mass of the galaxy.

This discovery helps scientists conclude that this distant galaxy has twice the mass of stars visible from Earth.

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