Euclid has identified 31 very ancient quasars, including two record-setting objects seen when the universe was about 670 million years old. The pair have redshifts of 7.77 and 7.69, and ESA says their light comes from a time when the cosmos was roughly 5% of its current age. [1][2][3]
From a record to a census
A quasar is a galaxy whose central supermassive black hole is actively fed by surrounding gas and dust. As material falls inward, it heats up and releases extraordinary amounts of light — enough, in these cases, to be detected across more than 13 billion light-years. [1][2][3]
The important advance is not only the earliest object. Twelve of Euclid's detections have redshift 7 or greater, placing them in the universe's first 770 million years. ESA says that more than doubles the number of known quasars in that range. The first ten had taken roughly a decade to find; Euclid added more than ten in its first year of survey work. [1][2]
That changes the scientific task. Instead of interpreting a handful of exceptional bright sources one by one, researchers can begin to compare a larger population: how luminous the objects are, how common they may be and what their host galaxies were like. Euclid's infrared imaging is designed for this kind of wide-area search, and its eventual Wide Survey is meant to cover more than one third of the sky. [1][3]
What the new sample does — and does not — answer
The finds do not by themselves explain how supermassive black holes grew so quickly, or settle the role early galaxies played in reionizing the universe. They make those questions more testable by supplying targets that can be followed up with other observatories. [1][3]
For learners, the useful shift is from a single spectacular “oldest” headline to a measurement problem: redshift is a way of locating light in cosmic time, while a survey is a way of finding enough examples to test a pattern. [1][2]
