Euclid telescope spots most ancient quasars yet

The European Space Agency's Euclid telescope, launched in 2024, has detected 31 quasars from the universe's infancy, a period when it was only 670 million years old. This discovery, published on July 6, 2026, more than doubles the number of known ancient quasars.

Quasars emit primordial light and are often mistaken for closer celestial bodies. However, their detection provides astronomers with crucial information about the earliest stages of the universe. The light from these distant quasars is "redshifted," meaning its wavelengths are stretched into the red spectrum due to the expansion of the universe.

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Before, we could only find a handful of the very brightest ancient quasars, but Euclid lets us search far more efficiently across huge areas of [the night sky] to capture much fainter light. It's a unique tool for quasar hunting.

Previously, astronomers could only find a few of the brightest ancient quasars. Daming Yang, lead author of the study, stated that Euclid's ability to efficiently search vast areas of the night sky allows for the capture of much fainter light. This makes it a unique tool for identifying quasars. It took over a decade to find the first 10 quasars with a redshift of 7 or higher, while Euclid has found more than that in its first year of operation. Antonio La Marca, an ESA Research Fellow on the Euclid team, highlighted that this finding greatly expands the known population of ancient quasars.

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This finding more than doubles the number of quasars we know of that are so ancient.