The early universe is easy to imagine as mostly empty darkness waiting for galaxies to get organised. Euclid has made that picture look much busier. The space telescope has found 31 exceptionally old quasars, including two from when the universe was only about five percent of its current age.
The Euclid result described by NASA includes 12 quasars from the first 770 million years after the Big Bang. The two oldest formed within the first 670 million years, and their light has taken roughly 13 billion years to reach us. A quasar is powered by matter heating up as it falls towards a supermassive black hole, producing enough light to outshine the surrounding galaxy.
What gets me is the amount of structure implied by that. The universe had to make galaxies, feed enormous black holes, and turn some of them into absurdly bright beacons while it was still cosmically young. Finding them is difficult because that ancient light is faint and can be confused with stars, so 31 is not just a nice collection of distant dots. It gives astronomers a better sample for working out how the first galaxies and black holes grew together.
Euclid’s main job is mapping billions of galaxies to study dark energy, but discoveries like this are the fun reminder that large surveys rarely answer only one question. NASA’s Roman Space Telescope should build on the same work. For now, I just like knowing that some of the oldest light we can see came from black holes already making a ridiculous amount of noise.
