HomeOutdoorsNewsAstronomers Capture Radio Signals 9 Billion Light-Years Away From Earth

Astronomers Capture Radio Signals 9 Billion Light-Years Away From Earth

by Brett Stayton
A Galaxy Far Far Away In Outer Space
Photo by Tony Rowell/Getty Images

A radio signal from 9 billion light-years away from Earth has been recorded. It’s a new record for the most distant galaxy from which astronomers have ever detected a radio signal. The wavelength was picked up by the Giant Metrewave Radio Telescope in India. According to Space.com, the specific signal that was detected is known as the “21-centimeter line.” It’s also known as the “hydrogen line” because the wavelength is emitted by neutral hydrogen atoms. The discovery could very well open the door for astronomers to start investigating the oldest stars and galaxies in space.

The signal stems from a galaxy far, far away named SDSSJ0826+5630. Based on the frequency of the radio signal, it was determined to have been emitted when the Milky Way, the galaxy where Earth is, was just 4.9 billion years old. Our galaxy is now 13.8 billion years old. The radio signal was enough information for astronomers to measure the galaxy’s gas content. They determined its mass is more than double that of other early galaxies’ visible stars.

Galaxies emit light in the form of electromagnetic radiation across a wide range of radio wavelengths. 21-centimeter wavelengths have only ever been detectable from much closer galactic sources though. Arnab Chakraborty, a cosmologist with the McGill University Department of Physics, explains. “It’s the equivalent to a look-back in time of 8.8 billion years. A galaxy emits different kinds of radio signals. Until now, it’s only been possible to capture this particular signal from a galaxy nearby, limiting our knowledge to those galaxies closer to Earth.”

Using Gravity To Detect Radio Waves From Outer Space, Our Galaxy

As radio signals from distant galaxies reverberate across space, electromagnetic radiation causes their energy to reduce. That means detecting long-wavelength low-energy radio waves as the recent discovery needs the help of gravity. In this case, scientists used Einstein’s theory of general relativity to their advantage.

If you imagine a blanket stretched out with a ball in the center, the sheet would be weighed down and curved around the ball. The greater the mass, or heavier the ball, the more extreme the curvature. So if you were laying below the blanket, and looking up, the part of the blanket weighed down by the ball would look closer to you than the rest of the blanket. A bowling ball would look closer than a baseball because it has greater mass.

With that in mind, you can now imagine kind of what a black hole or galaxy does to outer space. The curving of spacetime causes light to bend as it passes by these massive objects. This creates a phenomenon known as gravitational lensing. That phenomenon magnifies light sources like electromagnetic radiation. If you know what to look for, you can use these gravitational lenses to naturally magnify telescopic images.

In this instance, the record-breaking radio wave being emitted from SDSSJ0826+5630 was bent by another closer galaxy that acted as a magnifying glass in this situation. “This effectively results in the magnification of the signal by a factor of 30, allowing the telescope to pick it up,” said Nirupam Roy, an Associate Professor in the Department of Physics at the Indian Institute of Science.

Additionally, the team of astronomers who made the discovery believe their find could open new doors. Because they proved it’s feasible to overserve radio signals from galaxies so far, far away, it could change how astronomers utilize telescopes.

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