Rosa Rubicondior: How Science Works - Challenging The Consensus

Quasars discovered by Euclid

The earliest quasars yet observed are shedding light on the infancy of our cosmos | The Current

Creationists have to explain away why the long-predicted abandonment of 'Darwinism' by biomedical scientists has not yet taken place despite the almost daily assurance that this is imminent for the last half a century, by claiming without a shred of evidence that scientists are prohibited from publishing anything which challenges the current consensus, and that the peer-review process is designed to filter out these papers.

The irony appears to be entirely lost on creationists, many of whose own propaganda organisations openly impose exactly the doctrinal censorship they falsely attribute to science. Answers in Genesis (AiG) requires its employees and volunteers to accept its Statement of Faith, which declares in advance that Genesis 1–11 is a factual account of real events. AiG also requires full-time employees to reaffirm that statement annually and subjects everything it publishes to an editorial board charged with preventing any departure from its approved biblical position. Similarly, the Institute for Creation Research (ICR) explicitly states that, whenever scientific evidence appears to conflict with the Bible, “the Bible must govern”, and requires its faculty and board members to sign its doctrinal statement every year.

In other words, creationist organisations begin with conclusions that may not be questioned and permit evidence to be published only when it can be made to support those conclusions. Scientific peer review does the opposite: it scrutinises the evidence, methods and reasoning while leaving the conclusions open to revision. Accusing science of enforcing the very dogmatic censorship that creationist organisations practise openly looks less like criticism than projection.

The scientific literature is, in fact, full of discoveries that expose weaknesses in existing explanations and force researchers to reconsider accepted models. Creationist claims to the contrary are generally made in the safe expectation that their followers will neither read the relevant papers nor understand what those papers actually say.

One recent example is a paper published in Astronomy & Astrophysics reporting the discovery of 31 previously unknown quasars in the early Universe using data from the European Space Agency’s Euclid space telescope. Twelve have redshifts of 7 or greater, more than doubling the number previously known from that period. The two most distant, with redshifts of approximately 7.69 and 7.77, are the earliest quasars yet observed, existing when the Universe was only about 670 million years old.

Quasars are intensely luminous objects powered by matter falling into supermassive black holes at the centres of galaxies. These early examples radiated with the brilliance of roughly a trillion Suns. Their existence presents astrophysicists with a major problem: how did black holes grow to hundreds of millions, or even billions, of solar masses so soon after the Big Bang? Current models include the formation of unusually massive black-hole ‘seeds’, exceptionally rapid accretion and mergers, but astronomers do not yet know which processes, or combination of processes, can account for the observations.

This does not mean that the Big Bang has been disproved or that cosmology is collapsing. It means that existing models of the formation and early growth of supermassive black holes are incomplete and must now be tested and improved. In everyday language, the scientists are saying, “We have found something that our present explanations cannot yet account for satisfactorily. We need more observations, better models and, where necessary, a change of mind.” That is not a failure of science; it is science working exactly as it should. To the simplistic mind of a creationist however, such 'confessions' by scientists are evidence of the failure of science because, to their way of thinking, if science is not 100% accurate then it is 100% inaccurate and completely unreliable.

Now imagine a creationist discovering compelling evidence that Genesis is a composite work assembled from several older traditions over a prolonged period. Would AiG or the ICR conclude that this required a fundamental reassessment of biblical inerrancy, a literal six-day creation or a global genocidal flood? Would their editorial boards publish a paper concluding that their founding beliefs were wrong? Or would the evidence simply be rejected, ignored or reinterpreted until it could be made to conform to conclusions that had already been declared unalterable?

The difference is not that science has no consensus or that scientists never resist new ideas. It is that scientific conclusions remain answerable to evidence. However firmly an explanation may be established, sufficiently strong contrary evidence can force it to be modified or abandoned. Creationism reverses that process: the conclusion is fixed in advance, and the evidence is accepted, rejected or distorted according to whether it supports the required belief, and the greater the evidence the greater the victory over it.

The paper was produced by a large international collaboration led by Daming Yang of Leiden University and including Professor Joseph Hennawi, who holds joint appointments at Leiden University and the University of California, Santa Barbara.

Early Quasars, Scientific Anomalies and Changing the Consensus. Why are early quasars puzzling?

A quasar is the intensely luminous region surrounding a supermassive black hole at the centre of a galaxy. Gas and dust falling towards the black hole form a rapidly rotating accretion disc, where friction and compression heat the material until it radiates enormous quantities of energy. A quasar can therefore outshine all the stars in its host galaxy.

The quasars discovered by the Euclid survey are being observed as they existed during the Universe’s first 670–800 million years. Their presence adds to an important unresolved problem: how did supermassive black holes form and grow so rapidly when the Universe was still so young?

Black holes can increase their mass by:

accreting surrounding gas and dust;

merging with other black holes; and

beginning as comparatively massive ‘seed’ black holes.

However, ordinary stellar-mass black holes growing at conventional rates may not have had enough time to become the hundreds-of-millions- or billions-of-solar-mass objects known to power some quasars within the first billion years of cosmic history. Astronomers are therefore investigating several possibilities, including unusually massive initial seeds, sustained periods of very rapid accretion, frequent mergers, or some combination of these processes.

The Euclid discoveries do not show that the Big Bang theory is wrong, nor that modern cosmology has collapsed. They show that present models of the formation and early growth of supermassive black holes remain incomplete.

What happens when evidence challenges a scientific consensus?

A scientific consensus is not an article of faith, an official doctrine or a conclusion that scientists are forbidden to question. It is the provisional judgement of specialists about which explanation is best supported by the available evidence.

When an observation appears inconsistent with that explanation, scientists do not immediately discard the whole body of established knowledge. They first ask whether:

the observation or measurement could be mistaken;

the sample was affected by selection bias;

an assumption in the existing model was unjustified;

the anomaly can be reproduced independently; or

a revised or alternative model explains all the evidence better.

If the anomaly survives those tests, the relevant part of the consensus must be modified or, in exceptional cases, replaced. The new explanation must account not only for the surprising discovery but also for the evidence that made the previous model successful.

This is why publishing an unresolved problem does not demonstrate a failure of science. It demonstrates that scientific conclusions remain answerable to evidence. Scientists publicly identify conflicts, uncertainties and gaps in their understanding because those are opportunities to test ideas and improve explanations.

Dogma works in the opposite direction: the conclusion is declared true in advance, and inconvenient evidence must be rejected, ignored or forced into conformity with it. Science changes its conclusions when the evidence demands it; creationism demands that the evidence be changed to protect its conclusions.

The discovery and its implications were also described by science writer Harrison Tasoff in The Current, UC Santa Barbara’s news publication:

The earliest quasars yet observed are shedding light on the infancy of our cosmos
Quasars are among the brightest, most energetic objects in the universe, powered by supermassive black holes devouring matter at the centers of galaxies. Their extreme luminosity makes them visible across tremendous cosmic distances.
An international team of scientists has discovered 31 of the most ancient quasars ever found. Two of these are the earliest yet observed in cosmic history. They radiated the light of a trillion suns back when the universe was a mere 670 million years old. The findings, published in the journal Astronomy & Astrophysics, mark a significant step forward in our understanding of the early universe.
These objects provide the best clues for understanding how supermassive black holes form. These monsters — weighing billions of times the mass of our sun — somehow already existed when the universe was in its infancy. We don't yet have a good understanding of how they grew so massive, so fast.

Professor Joseph Hennawi, co-author
Department of Physics
UC Santa Barbara, Santa Barbara, CA, USA
and Leiden Observatory
Leiden University
Leiden, Netherlands.

Bright, yet elusive

Astronomers have been hunting for the universe’s very first quasars for decades. These objects reveal what was happening during the cosmos’ earliest days, including how the first supermassive black holes and galaxies took shape.

Yet, quasars from earlier than about 770 million years after the Big Bang are exceedingly rare and difficult to detect. Few galaxies had yet grown large enough to create a quasar. Even then, the light from these primordial quasars is both faint and easily mistaken for signals from stars lying closer to us.

What’s more, their light is stretched from ultraviolet into near-infrared wavelengths by cosmic expansion, falling into a range where Earth’s atmosphere glows brightly, drowning out faint signals. Scientists actually use this “redshift” as a measure of an object’s age and distance, since light from farther away (and thus earlier in the life of the universe) has been shifted more toward longer wavelengths by the subsequent expansion of spacetime.

A redshift of 7 takes us to when the universe was just 750 million years old, less than 6% of its current age.

Professor Joseph Hennawi.

These two things make finding quasars at these distances incredibly difficult. For every one of them there are thousands of stars in our Milky Way and nearby galaxies that look almost identical in the imaging surveys. And since their light is stretched to the infrared at such distances, we need a survey that is both wide enough to capture these rare objects and deep enough to detect their faint light.

Daming Yang, lead author
Leiden Observatory
Leiden University
Leiden, The Netherlands.

The task is nearly impossible to carry out on the ground. You need to get a view from space.

An artist impression of ESA’s Euclid mission in space.
Photo Credit: European Space Agency.

The Euclid Space Telescope was developed to measure the accelerating expansion of the universe so scientists could better understand dark matter, dark energy, and the early cosmos.

Eye in the sky

In 2023, the European Space Agency (ESA) launched the Euclid space telescope to help demystify this era of ancient cosmic history. It views the universe from above our planet’s infrared haze, surveying an area of the sky far larger than ground-based observatories could cover at comparable depth. The telescope has now discovered an unprecedented number of 31 new quasars in the early universe, pushing back to a time when the cosmos was just 5% of its current age. These appeared in data from the Euclid Wide Survey, which will cover more than one-third of the total sky once complete.

The earliest quasars we knew of until now were the rare, bright outliers that had been easiest to spot. We hadn’t yet found enough quasars from the universe’s early days to study them properly as a group.

Euclid is a true game-changer. 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. It’s a unique tool for quasar hunting.

Daming Yang.

Beacons from the early universe

The second most ancient quasar found by Hennawi, Daming and their colleagues was recently studied in more detail. The analyses revealed that the quasar was embedded in a dusty, gas-filled galaxy that was furiously forming new stars, hinting at what the host galaxy of an early supermassive black hole may have been like.

These quasars hark back to a fascinating period in cosmic history — known as the epoch of reionisation — when the first stars and galaxies ionized the dark, neutral hydrogen fog filling the early universe. This was a crucial era that set the stage for everything we see today.

Of the 31 new quasars, 14 are at or above a redshift of 7. The two most ancient of the batch have redshifts of 7.69 and 7.77, setting a new record for the earliest quasars ever found. Both lie just over 13 billion light-years away, and emerged during the universe’s first 670 million years. They also break the previous record for earliest quasar that Hennawi’s group set back in 2021.

But each new record isn't just a record for its own sake.

Every step further back in time makes the puzzle more perplexing: How did the Universe produce supermassive black holes so quickly? We're finding black holes with hundreds of millions of times the mass of our sun at a time when the universe was barely getting started.

Professor Joseph Hennawi.

Answering this quandary will require looking even farther into our cosmic past.

A small orange dot in the middle of a deep-field view of space.
Photo Credit: ESA/Euclid/Euclid Consortium/NASA

Hiding in the deep-field of Euclid’s sky survey, EUCL J1729 is the most distant quasar astronomers have yet observed.

Pushing ever earlier

A combination of better telescopes and smarter searches have enabled astronomers to continue peering deeper into the universe’s history. Discovering the first 10 or so quasars at a redshift of 7 or above took astronomers more than a decade — but Euclid has already discovered more than that in a single year. This finding more than doubles the number of quasars we know of that are so ancient.

In addition to revolutionary observatories like Euclid, new machine-learning methods enable scientists to sift through tens of millions of sources and reliably pick out the handful of real quasars from the far more common imposters, Hennawi explained.

Hennawi’s group has spent years developing the algorithms that proved critical in these recent discoveries. He’s also the lead developer of PypeIt, the software that astronomers at the University of California use to process the data that they collect at the Keck telescopes. Two-thirds of these new quasars, including the three most distant ones, were discovered with Keck through the UC’s privileged access.

The team’s new goal is to push the distance frontier even further, and find the first quasar beyond redshift 8. That would place it within the first 630 million years of the universe’s lifetime.

But discovery is just half the story. The team already has approved programs with the James Webb Space Telescope to study many of these quasars in detail, including measuring the masses of their black holes, probing the chemistry of the gas around them, and using the imprint of the intergalactic medium on their light to trace how reionization progressed. Meanwhile, telescopes like the Atacama Large Millimeter Array will target the cosmic dust glowing in the host galaxies themselves, revealing aspects about their dust, gas and star formation.

The bigger vision is to stitch all of this together into a coherent timeline, a quasar chronicle of the first billion years

Professor Joseph Hennawi.

Daming Yang, Antoine Basset and Jean-Charles Cuillandre of the Euclid Consortium contributed to this story.

Publication:
D. Yang; J. F. Hennawi; F. Guarneri; et al (2026)
Euclid: Discovery of 31 new quasars at 6.6 < z < 7.8
Astronomy & Astrophysics 711 A104 DOI: 10.1051/0004-6361/202658883

Abstract

We report the discovery of 31 new high-z quasars in the redshift range 6.6 < z < 7.8. These quasars were selected from approximately 3000 deg² of sky covered during the first 1.5 years of the Euclid Wide Survey, representing the initial results of the Euclid high-z quasar search. Our candidate selection employed multiple machine-learning and probabilistic techniques applied to the EuclidI_E, Y_E, J_E, and H_E images, supplemented by ancillary z-band data when available. Spectroscopic follow-up observations were carried out with Keck, Magellan, and the Large Binocular Telescope (LBT). Among the new discoveries, there are 12 quasars at z ≥ 7, more than doubling the number of previously known quasars at z ≥ 7. The newly discovered quasars exhibit 21.2 < J_E < 23.2 (−25.5 < M₁₄₅₀ < −23.6), extending quasar studies to the faint end of the quasar luminosity function (QLF) at z ≳ 7. The quasar with the highest-z, EUCL J172902.75+641018.1 at z ≈ 7.77, sets the new redshift record for the most distant quasar ever reported. These discoveries demonstrate Euclid’s transformative role in high-z quasar discovery and set the stage for future follow-up studies of the early galaxies hosting quasars, supermassive black hole growth, and the intergalactic medium in the epoch of reionisation.

Projection of the EWS area and the locations of the newly discovered quasars in J2000.0 equatorial coordinates. The regions observed by 11 August 2025, utilised for the quasar search presented in this work, are shown in beige. The full survey footprint expected by the end of the mission in 2030 is overlaid in cyan. The positions of newly discovered Euclid high-z quasars are marked in red.

D. Yang; J. F. Hennawi; F. Guarneri; et al (2026)
Euclid: Discovery of 31 new quasars at 6.6 < z < 7.8
Astronomy & Astrophysics 711 A104 DOI: 10.1051/0004-6361/202658883

Copyright: © 2026 The authors.
Published by The European Southern Observatory on behalf of the Euclid Consortium . Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

The discovery of these extraordinarily early quasars is therefore not evidence that science suppresses challenges to its prevailing ideas. It is evidence of the opposite. The observations were published precisely because they expose a serious problem for current models of how supermassive black holes formed and grew. Far from being concealed, the anomaly has been presented openly so that other scientists can test the findings, propose explanations and determine which parts of the existing models need to be revised.

That is how genuine science progresses. A scientific consensus is not protected by declaring contrary evidence inadmissible; it survives only for as long as it remains the best explanation of the evidence. When new observations reveal that it is incomplete, scientists do not need to pretend that the observations are false or that the Universe has somehow failed to behave properly. They change the model, not the evidence.

Creationism, by contrast, begins with a conclusion that may never be surrendered. No discovery can be permitted to show that Genesis is wrong because the creationist organisation has already declared Genesis to be infallible. Evidence may be accepted, distorted or rejected, but the doctrine itself remains beyond examination. That is not scientific conservatism; it is institutionalised confirmation bias.

So when creationists accuse scientists of suppressing dissent, they are describing their own methods, not those of science. The early quasars are being studied because they challenge existing explanations. Creationist claims are protected because they must not be challenged at all. One system treats anomalies as opportunities to learn; the other treats them as threats to be explained away. Only one of those approaches has any realistic prospect of improving our understanding of the Universe.

Science teaches us how to think; religion teaches us not to think.

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