Maarten Schmidt, who in 1963 became the first astronomer to identify a quasar, a small, intensely bright object several billion light years away, and in the process upended standard descriptions of the universe and revolutionized ideas about its evolution, died on Sept. 17 at his home in Fresno, Calif. He was 92.
His daughter Anne Schmidt confirmed the death.
Dr. Schmidt’s discovery of what was then among the farthest known objects in the universe answered one of the great conundrums of postwar astronomy, and like all great breakthroughs it opened the door to a whole host of new questions.
Advances in radio technology during World War II allowed scientists in the 1950s to probe deeper into the universe than they could with traditional optical telescopes. But in doing so they picked up radio signals from a plethora of faint or even invisible, but intensely energetic, objects that did not fit with any conventional category of celestial body.
Researchers called them “quasi-stellar radio sources,” or quasars, for short — even though no one could figure out what a quasar was. Many thought they were small, dense stars nearby, within the Milky Way.
In 1962, two scientists in Australia, Cyril Hazard and John Bolton, finally managed to pinpoint the precise position of one of these, called 3C 273. They shared the data with several researchers, including Dr. Schmidt, an astronomer at the California Institute of Technology.
Using the enormous 200-inch telescope at the Palomar Observatory, in rural San Diego County, Dr. Schmidt was able to hone in on what appeared to be a faint blue star. He then plotted its light signature on a graph, showing where its constituent elements appeared in the spectrum from ultraviolet to infrared.
What he found was, at first, puzzling. The signatures, or spectral lines, did not resemble those of any known elements. He stared at the graphs for weeks, pacing his living room floor, until he realized: The expected elements were all there, but they had shifted toward the red end of the spectrum — an indication that the object was moving away from Earth, and fast.
And once he knew the speed — 30,000 miles a second — Dr. Schmidt could calculate the object’s distance. His jaw dropped. At about 2.4 billion light years away, 3C 273 was one of the most distant objects in the universe from Earth. That distance meant that it was also unbelievably luminous: If it were placed at the position of Proxima Centauri, the closest star to Earth, it would outshine the sun.
Dr. Schmidt shared his results with his colleagues, and then in a paper in the journal Nature — and not without trepidation, knowing how disruptive his findings would be.
“At that time it was simply a matter of knowing that nature forced you to say something,” he said in an interview for the American Institute of Physics in 1975. “You couldn’t keep quiet and you had to say something and it better be good because it was clear it was an occasion.”
The revelation shocked the astronomy world, and for a time made Dr. Schmidt something of a celebrity. Time magazine put him on its cover in 1966, with a fawning profile that compared him to Galileo.
“The 17th century Italian startled scientists and theologians alike; the 20th century Dutchman has had an equally jarring effect on his own contemporaries,” Time wrote, a bit breathlessly but not inaccurately.
The question remained: If these objects weren’t stars, what were they? Theories proliferated. Some said they were the fading embers of a giant supernova. Dr. Schmidt and others believed instead that in a quasar, astronomers could see the birth of an entire galaxy, with a black hole at the center pulling together astral gases that, in their friction, generated enormous amounts of energy — an argument developed by Donald Lynden-Bell, a physicist at Cambridge University, in 1969.
If that was true, and if quasars really were several billion light years away, it meant that they were portraits of the universe in its relative infancy, just a few billion years old. In some cases their light originated long before Earth’s solar system was even formed, and offered clues to the evolution of the universe.
Maarten Schmidt was born on Dec. 28, 1929, in Groningen, the Netherlands. His father, Wilhelm, was an accountant for the Dutch government; his mother, Annie Wilhelmina (Haringhuizen) Schmidt, was a homemaker.
Maarten built his first telescope under the tutelage of his uncle, a pharmacist and amateur astronomer, using two lenses and a toilet-paper roll. Though his family lived in central Groningen, the exigencies of World War II often meant a complete blackout of the city, allowing him a clear view into the heavens.
He read all the astronomy he could find, and proved so adept that one high school teacher let him lead the class. He studied math and physics at the University of Groningen, receiving a bachelor’s degree in 1949 and a master’s degree a year later.
He then traveled to the University of Leiden, south of Amsterdam, where he studied under the renowned Dutch astronomer Jan Oort — known, among other things, for his theory about a layer of icy objects just beyond the solar system, now called the Oort Cloud.
Dr. Oort liked to throw parties, and at one, Mr. Schmidt met Cornelia Tom. They married in 1955. She died in 2020.
Along with his daughter Anne, he is survived by his daughters Elizabeth Evans and Marijke Schmidt, four grandchildren and five great-grandchildren.
Dr. Schmidt received his doctorate in 1956 and spent two years in the United States on a Carnegie Fellowship. He and his young family returned to Leiden, but he was dissatisfied with the resources and opportunities available to him, and in 1959 accepted a permanent position at Caltech, in Pasadena.
He spent most of his later career hunting quasars and uncovering new insights about them, a pursuit interrupted by several years as an administrator, running Caltech’s Division of Physics, Mathematics and Astronomy and directing the school’s Hale Observatories.
Dr. Schmidt was an adamant atheist, but when the editors of the book “Origins: The Lives and Worlds of Modern Cosmologists” (1990) asked him how, if he were God, he would have designed the universe, he gladly took up the challenge.
“I would have constructed a bigger universe,” he said. “I think the universe is small.”