“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
If you take the world’s most powerful space telescope, point it into the cosmic abyss for days, and collect all the light possible, you’ll see something fantastic.
But you won’t see the Universe’s most distant galaxy.
The most distant galaxy ever discovered comes from when the Universe was only 400-million-years-old, 3% of its current age.
It took four separate circumstances coming together all at once to make its discovery possible.
1) The Universe is expanding, meaning that the wavelength of the emitted light gets stretched as it journeys throughout the Universe. We had to look in the infrared for light that was emitted in the ultraviolet, at more than double the wavelength limit of visible light.
2) The galaxy happens to be located where there’s no intervening neutral gas, since that would block the light we could see.
A reionized region this early is rare, and purely serendipitous.
3) We had to look near a very large mass, so that the Einsteinian effect of gravitational lensing could magnify the background galaxy. And…
4) We needed spectroscopic confirmation, to know this wasn’t simply an intrinsically red/infrared object.
Hubble’s record-holder, GN-z11, will likely stand until James Webb comes online.
We’ve gotten very lucky.
Mostly Mute Monday tells the astronomical story of an object, phenomenon or discovery in visuals, pictures and no more than 200 words.