“We’ve taken a major step back in time, beyond what we’d ever expected to be able to do with Hubble. We see GN-z11 at a time when the universe was only three percent of its current age.” -Pascal Oesch
Arriving at our eyes after a journey of 13.4 billion years, the light from galaxy GN-z11 has been traveling towards us for 97% of the Universe’s present age. It’s detection and discovery, however, was a lot more complicated than simply opening up your telescope’s eyes and collecting enough light; a confluence of four separate things needed to happen all at once to make it possible.
The telescope itself needed to be configured to detect light that had been shifted by the Universe’s expansion from ultraviolet to infrared. The volume of the Universe, from here to there, needed to be reionized enough to allow light to pass through it. Gravitational lensing needed to magnify the background galaxy to make it detectable. And spectroscopic confirmation was needed to ensure that the galaxy wasn’t an impostor.