Astronomers announced today that they’ve located the most distant galaxies ever seen, 13.2 billion light-years away, formed when the Universe was only 500 million years old.
Galaxies that far away can’t easily be seen directly with current telescopes. Instead, the researchers turned massive clusters of galaxies into natural telescopes, using a technique called gravitational lensing. As the light from the more distant galaxies passed the galaxy clusters, it was bent by gravity towards the Earth.
This allowed the (already powerful) 10-metre Keck II telescope to capture additional photons, and measure these distant galaxies. The researchers were able to locate 6 faint star forming galaxies, thanks to the assistance of the gravitational lens, which boosted the signal by about 20 times.
When the Universe was only 300,000 years old, it entered a period called the Dark Ages when no stars were shining. Astronomers have been trying to pinpoint the moment when it came out of this opaque period, and the first stars formed. The combined radiation of these galaxies should be strong enough to break apart the hydrogen atoms around them, ending the Dark Ages. So astronomers could be seeing these galaxies at the moment the Dark Ages ended.