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. The New York Times reports: 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. […] 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. […] For their work on quasars, in 2008 Dr. Schmidt and Dr. Lynden-Bell shared the prestigious Kavli Prize in Astrophysics.