The early universe was a very different place from the cosmos we see today. Galaxies were still forming, stars were beginning to transform their surroundings, and some of the universe's first supermassive black holes were already producing enormous amounts of energy.

Astronomers call these extraordinarily bright objects quasars. Because their light can travel for more than 13 billion years before reaching Earth, distant quasars act like cosmic time machines. By studying them, scientists can investigate what the universe looked like when it was only a small fraction of its current age.

Recent observations are making this research even more exciting. In 2026, ESA's Euclid mission discovered 31 quasars at redshifts between 6.6 and 7.8, including two that are currently the most distant quasars observed. Their light comes from a time when the universe was only about 670 million years old.

What Is a Quasar?

A quasar is an extremely luminous active galactic nucleus (AGN) powered by a supermassive black hole at the center of a galaxy.

The black hole itself does not shine like a star. Instead, enormous amounts of gas and dust can spiral toward it. As this material forms an accretion disk, friction and intense gravitational effects heat the gas to extreme temperatures.

The resulting radiation can make a quasar brighter than the combined light of many billions of stars.

This extraordinary brightness is what makes ancient quasars so useful to astronomers. Even though they are incredibly distant, their powerful radiation can still be detected by telescopes on and around Earth.

How Do Astronomers Find Ancient Quasars?

Finding a quasar from the early universe is challenging.

As the universe expands, light traveling through space is stretched toward longer wavelengths. This phenomenon is called cosmological redshift. Light from very distant quasars can therefore move from ultraviolet and visible wavelengths into infrared wavelengths.

Astronomers first search enormous areas of sky for objects with colors and brightness patterns characteristic of very distant quasars. Candidate objects are then examined with more powerful telescopes and spectroscopy.

Spectroscopy breaks light into its component wavelengths. The resulting spectrum contains features that allow researchers to measure a quasar's redshift and determine how far back in cosmic history its light originated.

The 2026 Euclid discovery is a good example. Euclid identified 31 ancient quasar candidates, while observations from ground-based facilities including the Keck Observatory and Subaru Telescope helped confirm many of them.

The New Quasar Record

The two most distant quasars in the 2026 Euclid study have redshifts of 7.77 and 7.69.

The quasar at redshift 7.77 is named EUCL J172902.75+641018.1. Its light shows the object as it existed when the universe was approximately 670 million years old.

These quasars were producing enormous amounts of energy at a remarkably early stage of cosmic history. Their discovery expands the population of known quasars from the universe's first billion years and gives researchers more objects to study statistically.

Why Are Ancient Quasars So Important?

They Show That Massive Black Holes Grew Very Early

One of the biggest mysteries is how supermassive black holes became so massive so quickly.

Astronomers have found black holes containing millions or billions of times the mass of the Sun during the universe's first billion years. Growing such enormous objects from ordinary stellar remnants requires substantial amounts of matter and time.

Ancient quasars provide direct evidence that powerful black-hole accretion was already occurring extremely early in cosmic history.

However, the observations do not yet establish exactly how these black holes formed.

Possible explanations include growth from ordinary stellar-remnant black holes, unusually massive initial seeds, rapid periods of accretion, or combinations of several processes.

Quasars Also Trace Early Galaxies

Quasars are connected to the galaxies that surround their central black holes.

Their powerful radiation can interact with surrounding gas, while their environments can contain neighboring galaxies and large reservoirs of material.

For example, NASA's James Webb Space Telescope previously studied a distant quasar surrounded by several galaxies. Webb's observations revealed a dense region of galaxy formation around the quasar, providing a glimpse of how massive structures were assembling in the early universe.

This means ancient quasars can act as signposts for studying both black-hole growth and galaxy formation.

Quasars and the Early Universe's Transformation

Another major scientific question concerns cosmic reionization.

After the Big Bang, the universe eventually cooled enough for neutral hydrogen to form. Later, the first stars and galaxies produced energetic radiation that gradually transformed much of this hydrogen into an ionized state.

Quasars can help astronomers investigate this transition because their powerful light interacts with the gas between galaxies.

By studying how quasar light is absorbed as it travels toward Earth, researchers can learn about the density and state of matter in the early universe.

A Related Discovery: Black Holes May Have Started Large

Webb observations are adding another important piece to the puzzle.

In 2026, researchers used JWST to study Abell2744-QSO1, an object that existed around 700 million years after the Big Bang. The team directly measured gas motions and estimated a black-hole mass of roughly 50 million solar masses. The black hole appeared to account for at least two-thirds of the object's total mass.

The researchers interpreted the observation as evidence supporting scenarios in which some early black holes may have formed from unusually massive seeds rather than growing only from ordinary stellar remnants.

That interpretation is significant—but it remains a scientific question under active investigation, rather than a final explanation for all ancient black holes.

What Remains Unknown?

The discovery of increasingly ancient quasars raises several major questions.

How did the first massive black-hole seeds form? Scientists are considering several possibilities, including the collapse of massive primordial gas clouds and other early-universe processes.

How did black holes grow so rapidly? Researchers need to understand how much material could fall into early black holes and how efficiently that material could be converted into black-hole mass.

How common were ancient quasars? The quasars discovered so far are extremely luminous and therefore easier to detect than less active black holes. Scientists do not yet know how representative they are of the overall early black-hole population.

These uncertainties are why discovering more ancient quasars is so important.

What Comes Next?

The next stage of research will involve finding much larger samples of high-redshift quasars and studying them with different observatories.

Euclid's enormous sky survey is particularly valuable because it can search large areas efficiently. Webb can then provide detailed infrared imaging and spectroscopy of selected targets.

Future observations should help astronomers determine how common early quasars were, measure their host galaxies, investigate their environments, and test competing models of supermassive black-hole formation.

Conclusion

Ancient quasars are among the most powerful windows into the early universe.

Their extraordinary brightness allows astronomers to study supermassive black holes, young galaxies, intergalactic gas, and cosmic reionization billions of years in the past. The discovery of quasars existing when the universe was only about 670 million years old shows that powerful black-hole activity began surprisingly early.

But the discoveries do not mean that scientists have solved the mystery of the first supermassive black holes. Instead, they have made the central questions sharper: How did the first black holes become so massive, how quickly could they grow, and what role did they play in building the first galaxies?

As Euclid, JWST, and ground-based observatories continue searching the distant universe, ancient quasars may provide some of the strongest evidence yet about how the modern cosmos began taking shape.

Frequently Asked Questions

1. What is an ancient quasar?

An ancient quasar is a quasar whose light has traveled for billions of years before reaching Earth, allowing astronomers to observe it as it existed during the early universe.

2. How do quasars get their enormous energy?

Quasars are powered by material falling toward supermassive black holes. The material forms an extremely hot accretion disk and releases enormous amounts of electromagnetic radiation.

3. What is the oldest quasar discovered so far?

As of 2026, ESA's Euclid mission reported the most distant quasars in its survey at redshifts of 7.77 and 7.69. They existed when the universe was about 670 million years old.

4. Do ancient quasars prove that scientists know how the first black holes formed?

No. They confirm that very powerful black holes existed extremely early, but their formation and rapid growth remain open scientific questions. Observations such as Webb's study of Abell2744-QSO1 provide evidence relevant to competing formation scenarios.

5. Why are scientists searching for more ancient quasars?

A larger sample allows researchers to determine how common early quasars were, measure their properties more accurately, study their host environments, and improve models of early black-hole and galaxy formation.