Cosmic Dawn Unveiled: Euclid Telescope Discovers Oldest Quasars Ever Seen, Shining with the Light of a Trillion Suns

GENEVA — In a monumental breakthrough that pushes the boundaries of the observable universe, astronomers have detected a treasure trove of 31 ancient, black-hole-powered quasars dating back to the infancy of the cosmos. Among this unprecedented haul are the two most distant and ancient quasars ever recorded, blazing so intensely that they outshine a trillion suns combined.

The cosmic titans were captured by the European Space Agency’s (ESA) Euclid space telescope, fundamentally shifting our understanding of how the earliest supermassive black holes and galaxies formed.

A Census at the Edge of Time

The historic discovery, detailed in a newly published study led by researcher Daming Yang of Leiden University, shatters previous observational records. Until now, hunting for these primordial beacons was an agonizingly slow process; it took astronomers over a decade to find just the first ten quasars from the universe’s earliest epochs. Euclid managed to triple that number in just a single year of observations.

Of the 31 newly cataloged objects, 12 emerged within the first 770 million years of cosmic history. However, two specific objects have stolen the spotlight: EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3.

Registering staggering cosmological redshifts of 7.77 and 7.69 respectively, these twin monsters boast light that has traveled for over 13 billion years to reach us. They were actively shining when the universe was just 670 million years old—a mere 5% of its current age.

"These early quasars date back to the universe's infancy," said lead author Daming Yang in a statement. "By finding and studying them, we can better understand how these enormous systems formed and grew so quickly—one of the greatest mysteries in astrophysics."

Powering a Trillion Suns

Quasars—short for "quasi-stellar radio sources"—are the most luminous objects in the known universe. They represent a chaotic, transient phase in a young galaxy's evolution.

At the heart of each quasar sits a supermassive black hole containing millions, or even billions, of times the mass of our Sun. As gravity pulls immense reservoirs of surrounding gas, dust, and stars into a rapidly spinning whirlpool known as an accretion disk, the extreme friction and gravitational forces heat the matter to millions of degrees.

This process releases a torrential flood of energy across the electromagnetic spectrum. The newly discovered record-breakers are so intensely energetic that their glowing accretion disks outshine the combined starlight of their entire host galaxies by hundreds to thousands of times, radiating the energy equivalent of 1,000,000,000,000 (one trillion) Suns.

Piercing the Cosmic Dark Ages

The timing of these quasars provides an unprecedented window into a pivotal era known as the Epoch of Reionization, which occurred roughly between 680 million and 1.1 billion years after the Big Bang.

Before this era, the universe was trapped in the "Cosmic Dark Ages"—a cold, dark expanse filled with neutral hydrogen gas that blocked light from traveling freely. As the first generation of stars and giant black hole engines ignited, their intense, high-energy ultraviolet radiation began stripping electrons from the hydrogen atoms (ionizing them). This effectively cleared the cosmic fog, turning the universe transparent and setting the stage for the modern cosmos.

Because these quasars are embedded within this transitional era, their piercing light acts as a cosmic flashlight. By analyzing how their light interacts with the surrounding primordial gas, scientists can map out exactly how and when the universe transitioned out of darkness.

Turning Euclid into a Cosmic Time Machine

Launched in 2023, the Euclid space telescope was primarily designed to map the "dark universe" by studying dark matter and dark energy. However, its massive wide-field survey capabilities—which will eventually cover one-third of the entire sky—have made it an unrivaled champion for hunting rare deep-space phenomena.

"Euclid is a true game-changer," Yang explained. "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 sky to capture much fainter light."

To confirm the discoveries, the Euclid Consortium collaborated with major ground-based facilities, utilizing deep imaging data from the Hyper Suprime-Cam on the Subaru Telescope in Hawaii to add crucial depth and color to the findings.

By capturing a true demographic "census" of the ancient quasar population rather than just a few bright outliers, astronomers are finally equipped to solve a compounding astronomical riddle: How did black holes grow to such monstrous, supermassive sizes so quickly after the dawn of time?

"Ancient quasars are rare discoveries," noted ESA Euclid Project Scientist Valeria Pettorino. "They're interesting in themselves, but also time machines that enable us to explore the early universe and understand how the first generation of galaxies came to be."