Astronomers using a radio telescope in India have captured the most distant-ever radio signal from a galaxy, fuelling hopes that the secrets of the early universe can be uncovered using existing telescope technology.
The signal came from a galaxy called SDSSJ0826+5630 that exists 8.8 billion light-years away. That essentially means that it exists closer to the Big Bang (when an infinitely hot and dense single point inflated to form our ever-expanding universe) than any other galaxy previously detected using radio astronomy.
They used a technique called gravitational lensing, a ripple in spacetime that allows background objects to be magnified in the extreme by foreground objects.
Radio signals become weaker the further away a galaxy is from Earth, making it difficult for current radio telescopes to pick up, but a new paper published this week in the Monthly Notices of the Royal Astronomical Society gives hope that probing galaxies at much greater distances from Earth may now be within reach.
“A galaxy emits different kinds of radio signals,” said Arnab Chakraborty, a Post-Doctoral Researcher who studies cosmology at the Department of Physics at McGill University in Montreal, Canada. “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.”
The researchers—from both from Montreal and India—used the Giant Metrewave Radio Telescope in Pune, India to capture the signal at a specific wavelength called the 21 cm line.
Gravitational lensing—sometimes called “nature’s magnifying glass”—occurs when the gravitational pull from a closer, but aligned galaxy distorts and bends the light from a distant star or galaxy, causing it to appear misshapen and be magnified—in this case by a factor of 30.
The signal from SDSSJ0826+5630 was emitted when the universe was only 4.9 billion years old, but because the universe is expanding it took 8.8 billion years to reach the telescope.
This breakthrough proves that it’s possible to observe faraway galaxies using with existing low-frequency radio telescopes. “This will help us understand the composition of galaxies at much greater distances from Earth,” said Chakraborty.
Radio astronomy is the study of the sky in radio frequencies. Stars, galaxies and other cosmic phenomena emit waves of light. Visible light is electromagnetic radiation, as are radio waves, gamma rays, X-rays, and infrared. So to get a full picture of what’s out there astronomers need to use radio telescopes to detect and amplify radio waves from space.
Wishing you clear skies and wide eyes.