The story
Settle yourself beneath an unhurried sky, and imagine that the air has grown clear enough for the constellations to seem less like drawings and more like distances. In Virgo there is a point of light called 3C 273. Through an ordinary telescope it does not announce its scale. It has the neat, concentrated appearance of a star, a small bright pin against the dark. Yet its light has been traveling toward you for about two and a half billion years. It began its journey long before the first humans looked up and gave names to the seasons, before Earth had its present arrangement of continents, before this planet’s night sky had any witness at all. The smallness of that point is an illusion of distance. It is not a star. It is the blazing heart of a faraway galaxy, briefly brighter than the galaxy around it.
To understand how such a thing can be, it helps to go back before Virgo had stars, before there were galaxies with centers, before even darkness had the familiar meaning it has tonight. The early universe was hot, dense, and expanding. As it cooled, the first simple atoms formed, chiefly hydrogen and helium. Gravity slowly gathered those atoms into denser places. The first stars ignited. Their light and their deaths made heavier elements, the materials that would one day become dust, rocky worlds, oceans, bodies, instruments, and eyes capable of wondering where the light had come from.
Galaxies assembled gradually, not as still islands but as gatherings in motion. Gas streamed into them, stars formed, and galaxies passed near one another or merged. In the centers of most large galaxies, including our own Milky Way, there lies a supermassive black hole: a concentration of mass ranging from millions to billions of times the mass of the Sun. A black hole is not a cosmic vacuum cleaner, drawing in everything from afar. Beyond its event horizon, its gravity behaves according to the same broad rules as the gravity of any other object with the same mass. A star can orbit a black hole, and gas can orbit one too. What matters is whether gas loses enough of its sideways motion, its angular momentum, to drift inward.
When a great deal of gas does begin that inward journey, a galaxy can enter an active phase. The gas does not usually plunge directly into the black hole. It circles, forming a flattened, whirling accretion disk. Within that disk, particles collide and magnetic fields help move energy and angular momentum around. Matter spirals inward. It is compressed, heated, and made incandescent. Some of the energy released by this descent becomes radiation: radio waves, infrared light, visible light, ultraviolet light, X-rays. The black hole itself remains dark, because light cannot return from inside its event horizon. The brilliance belongs to the matter outside, in its last luminous revolutions.
This is a quasar. It is not a separate species of star, and it is not the black hole alone. It is the compact, intensely radiant central region of a galaxy during a phase of abundant feeding. A quasar can be only roughly the scale of the Solar System in its brightest inner reaches, yet it can shine with the light of hundreds or thousands of whole galaxies. The Milky Way contains hundreds of billions of stars, and still an active central engine elsewhere can temporarily outshine all the starlight in its own host. A quasar is a place where a galaxy, for a while, becomes brighter than itself.
This understanding did not arrive all at once. In the middle of the twentieth century, the sky began to acquire a second appearance through radio astronomy. Radio telescopes found sources invisible to the eye, patches and points broadcasting long waves from the dark. Some could be matched with recognizable galaxies. Others offered little help. They appeared as powerful radio sources, but when astronomers searched for visible counterparts, they sometimes found only something that looked like an ordinary star.
One such object was called 3C 48. Its spectrum, made by spreading its light into a colored record of wavelengths, showed bright lines that did not easily correspond to known chemical patterns. Another was 3C 273, the apparently modest point in Virgo. Its designation came from a radio catalog, not from an ancient constellation tale. At first, the labels contained no explanation. They were simply careful names for puzzles.
The position of 3C 273 was refined through a lovely piece of celestial geometry. In Australia, radio astronomer Cyril Hazard and his colleagues used lunar occultations, watching what happened when the Moon moved in front of the radio source. As the Moon’s edge covered and uncovered the radio emission, timing revealed the source’s position more precisely. The Moon, familiar companion of human nights, became a measuring tool against a source billions of light-years away. Radio observations, optical observations, exact timing, and the work of people on different sides of Earth came together until the radio source could be associated with a star-like object visible through a telescope.
Then, in late December 1962, Maarten Schmidt observed the optical counterpart of 3C 273 at Palomar Observatory with the 200-inch Hale telescope. He found broad emission lines in the spectrum, but their pattern initially resisted interpretation. For a time, they were simply there: marks on a photographic record, clear enough to be real and strange enough to remain unresolved. This is how many discoveries begin, not with a sudden answer, but with patient attention to something that refuses to fit.
On February 6, 1963, Schmidt recognized the pattern as hydrogen’s Balmer series, shifted toward longer wavelengths by about sixteen percent. This shift, called a redshift, was most simply understood as the result of the expansion of the universe. If that reading was right, then 3C 273 was immensely distant. Schmidt’s calculation at the time placed it around two billion light-years away; later cosmological measurements place it at about two and a half billion light-years. The exact refinement mattered, but the central realization was already unmistakable. A source that looked star-like was not a nearby star at all. It was so far away that it had to be radiating roughly a hundred times as much light as a typical galaxy.
His paper appeared in March 1963, and the small mystery on the plate became a large fact about the universe. Once 3C 273 was understood, Schmidt and Jesse Greenstein recognized a similar, even greater redshift in 3C 48. The objects were soon called quasi-stellar radio sources, later shortened to quasars. The name preserves the first impression: they resembled stars in visible light and were first noticed as radio emitters. Yet many quasars are comparatively quiet in radio waves. The old name is a little fossil of uncertainty, left in the language after understanding moved onward.
There was still a difficult question. How could anything be so bright? The difficulty deepened because quasars varied. In the early observations, 3C 48 changed in brightness by about thirty percent over a year. Since no coordinated change can travel across an object faster than light, a source varying on that timescale could not be much larger than a few light-years across. A normal galaxy is at least around ten thousand light-years wide. Astronomers were being asked to accept a source far smaller than a galaxy, and yet bright enough to rival or exceed the combined light of many galaxies.
Some considered whether the redshifts might arise from gravity rather than cosmic expansion, or whether these peculiar objects might be much closer than they appeared. Such questions were reasonable at the edge of a new discovery. But the spectra, the growing evidence for cosmological distances, and the emerging physics of black holes gradually made the distant interpretation compelling. The solution was not that familiar laws had failed. It was that nature had found an extraordinary way to use them: by releasing gravitational energy from matter falling through a very deep gravitational well.
At the center of an active galaxy, the black hole is tiny compared with the galaxy that surrounds it. One NASA comparison likens the relative scale of a supermassive black hole and its galaxy to a penny compared with the entire Moon. Yet this tiny center can influence its vast surroundings. In some quasars, magnetic fields near the disk and black hole organize material into two narrow jets, pointing in opposite directions. The particles in these jets move at speeds close to that of light, and the jets may extend hundreds of thousands of light-years beyond the galaxy’s central region. The precise partnership of magnetic fields, disk motion, and black-hole spin remains an active subject of study, but the broad fact is serene and astonishing: a compact engine can send traces of its power far out into intergalactic space.
The feeding phase is not permanent. The Milky Way’s central black hole, Sagittarius A*, is now faint because it has little fuel available to it. A quasar needs a sustained supply of gas reaching inward. Interactions and mergers between galaxies can help disturb gas and guide some of it toward a galactic center, though not every merger makes a quasar, and quasar activity can arise through more than one route. The universe does not seem to favor a single script. Galaxies have their local histories of neighbors, gas, dust, star formation, and chance.
The light of a quasar can also push back on the galaxy that feeds it. Radiation, winds, and outflows from an active nucleus can carry gas outward at enormous rates. In some cases, winds move hundreds of solar masses of gas each year and travel at a few percent of the speed of light. Gas driven away or heated may no longer be available to make new stars. This process, called feedback, may help regulate how galaxies grow and may be connected to the observed relationship between a central black hole’s mass and the properties of its host galaxy. But the details are not settled into one universal rule. Astronomers continue to ask how often quasar winds truly halt star formation, how long their influence lasts, and when other processes are more important.
For a time, quasars were so brilliant that the galaxies around them were difficult to see. Then observations from the Hubble Space Telescope revealed their host galaxies more clearly. Some hosts looked disturbed or interacting; others seemed more ordinary. This was another gentle correction to an early image. A quasar is not an isolated beacon hanging alone in empty space. It is the active center of a galaxy, embedded in stars and gas, shaped by a past and capable of shaping a future.
And because their light travels slowly, quasars also become time machines. A distant quasar does not show you what it is doing now. It shows you what it was doing when its light began its long crossing. Along the way, that light passes through thin gas between galaxies. Atoms in the intervening gas absorb particular wavelengths, leaving dark markings in the quasar’s spectrum. Astronomers call the dense sequence of such marks a forest, and in that forest they can read the conditions of intergalactic space. The quasar is both the object being studied and the backlight that reveals the invisible material lying between it and us.
This is especially valuable for studying the epoch of reionization, the long early transition when radiation from the first stars, galaxies, and perhaps active black holes changed much of the hydrogen between galaxies from neutral to ionized. It was not a single switch thrown across the cosmos. It unfolded over time, unevenly, as light spread through a young universe. The farthest quasars send their light through remnants of that era, carrying faint evidence of the gas they encountered.
The search for such ancient quasars is difficult. They are rare. Their light is stretched by cosmic expansion, so radiation that began in ultraviolet or visible wavelengths reaches us as infrared. Closer stars can resemble them in broad survey images. To find them, astronomers need telescopes that can map wide regions of sky sensitively in infrared light, and then they need follow-up observations to distinguish a truly distant quasar from an impostor nearer to home.
In July 2026, the European Space Agency’s Euclid mission offered an important widening of this search. Euclid had launched in 2023 and begun routine science observations in 2024, chiefly to map the large-scale structure of the universe and investigate the dark universe. Yet its broad infrared survey is also well suited to catching rare, distant points of light. In an early census, Euclid identified thirty-one new quasars with redshifts between 6.6 and 7.8. They are seen as they were roughly six hundred to eight hundred million years after the Big Bang.
Twelve of those newly identified quasars have redshifts of seven or more, observed within the universe’s first 770 million years. Two, named EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3, have redshifts of 7.77 and 7.69. Their light shows them as they were when the universe was around 670 million years old, roughly five percent of its present age. That light has been traveling for just over thirteen billion years. The active regions shine with a luminosity of about a trillion Suns, though again it is the heated, orbiting matter around a black hole that produces that radiance, not the black hole in solitude.
The importance of Euclid’s work is not only that it extends a record. Thirty-one objects begin to make a sample large enough for a census. With more than a few rare examples, astronomers can ask how common early quasars were, how their brightnesses were distributed, how quickly their black holes must have grown, and what their spectra reveal about reionization. Euclid’s planned survey will cover more than one-third of the sky, offering many more chances to find these distant, improbable-looking points. Follow-up of one of its most distant quasars has already suggested a dusty, gas-rich host galaxy where star formation is vigorous. A brilliant black hole and a young galaxy may be growing amid the same rich supply of material.
Yet the earliest black holes remain one of astronomy’s softest and most compelling questions. How did some become so massive so soon? A black hole left by the death of a massive star would have to grow with remarkable speed to power a quasar before the universe was a billion years old. Perhaps some black holes fed rapidly for long intervals. Perhaps some experienced brief episodes of feeding beyond a conventional limit. Perhaps mergers helped. Perhaps some began from unusually large seeds, formed when immense primordial clouds of gas collapsed. The evidence has not chosen one route for all of them. It may be that the young universe had several ways of making a giant.
The James Webb Space Telescope has made that uncertainty richer. In its observations of the early universe, Webb found many compact red sources now called Little Red Dots. Some appear as early as roughly six hundred million years after the Big Bang and become less common by about one and a half billion years after it. Spectra suggest that many contain actively accreting black holes, but their nature is still being sorted out. Their redness may arise from dust, from dense gas, or from unusual ways that light is processed close to a growing black hole.
In 2025, Webb confirmed an actively growing supermassive black hole in one Little Red Dot called CANUCS-LRD-z8.6, observed only 570 million years after the Big Bang. Its radiation had ionized surrounding gas, and the observations indicated rapid motion around an accreting central source. The black hole appeared unusually massive compared with the stellar mass of its host. This does not overturn all that is known about galaxies, but it suggests that, in some early systems, black-hole growth and galaxy growth did not keep the proportions familiar in the nearby universe.
Then, in 2026, Webb examined another lensed Little Red Dot, Abell2744-QSO1. A foreground galaxy cluster bends and magnifies its light, producing three images and allowing unusual detail. The system is only about 1,300 light-years across and is observed as it was about 700 million years after the Big Bang. Webb mapped the motion of hydrogen gas and found a Keplerian pattern, the orderly signature expected from material orbiting a central mass. The inferred black hole has about fifty million times the mass of the Sun, perhaps around two-thirds of the system’s measured mass. The surrounding gas has less than half of one percent of the Sun’s metallicity, a sign of a chemically young environment.
It is tempting to say, from such a result, that black holes came before galaxies. But the quieter and more accurate thought is that this object supports the possibility that some black holes began from large seeds, or grew with exceptional speed before substantial stellar hosts had assembled. The evidence is remarkable, not final. The universe does not owe us a single explanation, and it is all right for the answer to remain beyond the edge of today’s observations.
Another Webb study of a lensed Little Red Dot, GLIMPSE-17775, found more than forty spectral lines, including a dense collection of iron lines. The observations fit a proposed picture in which a rapidly accreting black hole is enclosed in hot, dense, partially ionized gas. Researchers have called this possibility a black hole star, or BH-star. It does not mean an ordinary star made from a black hole. It is a suggested arrangement: a growing black hole embedded in a thick gaseous envelope that reprocesses the light produced within it. Such a cocoon might help explain why many Little Red Dots are red and faint in X-rays. It is a promising model, not a finished verdict.
A related object, an X-ray dot seen by Chandra and Webb, may offer another glimpse of that hidden growth. It resembles the Little Red Dots in several ways but emits X-rays unlike most of them. Perhaps its dense cocoon has become patchy, allowing high-energy light to escape. Or perhaps it is a more ordinary growing black hole obscured by unusual dust. One observation can narrow a field of possibilities without closing it, and there is something peaceful in that. Each measured line of light does not end the mystery. It gives the mystery a truer shape.
So return, at last, to 3C 273 in Virgo. It was close enough, by the standards of quasars, to become the first great clue. Its light began its journey when Earth was young in another way, and it reached twentieth-century instruments as a sharp point with a strange spectrum. From that point, astronomers learned to see an active galactic center where they had first seen something star-like. They found a black hole surrounded by brilliant falling matter, a compact engine able to rival the light of a galaxy, and a means of reading the thin gas spread across cosmic time.
Far beyond it, Euclid’s newly found quasars shine from an age when the universe was only about 670 million years old. Their ancient photons crossed expanding space for more than thirteen billion years before entering mirrors, detectors, and computers made by a species on one small world. They carry news of young galaxies, growing black holes, hydrogen slowly changing under the first widespread light, and beginnings that are still only partly understood.
Tonight, you do not need to solve what remains unsolved. You can let the unanswered questions rest where they belong, at the far horizon of knowledge. Somewhere in Virgo, 3C 273 continues its long, quiet appearance as a point of light. Somewhere farther still, early quasars burn in the past we are only now receiving. And all around you, the present night holds its own darkness gently, while the oldest light goes on arriving.