There are more than 20,000 galaxies in this field. This James Webb Space Telescope view is found between the Pisces and Andromeda constellations.
Researchers using Webb anchored their observations on quasar J0100+2802, an active supermassive black hole that acts like a beacon. It is at the center of the image above and appears tiny and pink with six prominent diffraction spikes.
The quasar is so luminous that it acts like a flashlight, illuminating the gas between it and the telescope. The team analyzed 117 galaxies that all existed approximately 900 million years after the Big Bang – focusing on 59 that lie in front of the quasar.
Credit: NASA, ESA, CSA, Simon Lilly (ETH Zurich), Daichi Kashino (Nagoya University), Jorryt Matthee (ETH Zurich), Christina Eilers (MIT), Rob Simcoe (MIT), Rongmon Bordoloi (NCSU), Ruari Mackenzie (ETH Zurich), Alyssa Pagan (STScI), Ruari Mackenzie (ETH Zurich)
Early galaxies’ stars allowed light to travel freely by heating and ionizing intergalactic gas, clearing vast regions around them.
Cave divers equipped with brilliant headlamps often explore cavities in rock less than a mile beneath our feet. It’s easy to be wholly unaware of these cave systems – even if you sit in a meadow above them – because the rock between you and the spelunkers prevents light from their headlamps from disturbing the idyllic afternoon.
Apply this vision to the conditions in the early universe, but switch from a focus on rock to gas. Only a few hundred million years after the Big Bang, the cosmos was brimming with opaque hydrogen gas that trapped light at some wavelengths from stars and galaxies. Over the first billion years, the gas became fully transparent – allowing the light to travel freely. Researchers have long sought definitive evidence to explain this flip.
New data from the James Webb Space Telescope recently pinpointed the answer using a set of galaxies that existed when the universe was only 900 million years old. Stars in these galaxies…