Maarten Schmidt, the Dutch-born American astronomer who explained the mysterious heavenly bodies known as quasars and in so doing helped create the modern picture of the universe, its structure and its history, died Sept. 17 at his home in Fresno, Calif. He was 92.
Through his groundbreaking work on quasars, Dr. Schmidt was credited with helping to revolutionize scientists’ understanding of the cosmos. He provided evidence for ideas and concepts now prominent in the public discourse, such as the big bang and black holes.
Quasars were found to be objects that, through unusual mechanisms, radiated enormous energies across expanses of space so vast as to seem almost limitless. Although neither stars nor planets, they seemed to share some properties of stars. Hence the name “quasar,” an abbreviation that recognized their starlike properties, and stands for quasi-stellar radio source.
In identifying these objects, and showing what and where they were, Dr. Schmidt made observations with one of the great scientific instruments of his day, the 200-inch-diameter reflecting telescope installed in the observatory at Palomar Mountain in California.
Wearing a heated flight suit as protection against the chill of the mountain night at Palomar, Dr. Schmidt aimed the giant telescope at the point in the sky that colleagues identified as the source of some of the unexplained energy reaching Earth from space.
Then, with photographs made with the telescope from the dim light that came from the same spot in the sky, Dr. Schmidt searched for clues to the mystery. He found his explanation in a phenomenon that science knows as the cosmological redshift.
That is the name for a shift in frequency — toward the red end of the spectrum — of light beamed by objects in an expanding universe, as they fly apart from one another in the wake of the big bang. The big bang was the event that set everything in motion.
What Dr. Schmidt recognized in his photographs was the spectrum of hydrogen, the characteristic pattern of light frequencies emitted by the excitation of the hydrogen atom that pervades the universe.
But the individual, discrete lines in the hydrogen spectrum had been shifted so that each had a wavelength 1.16 times greater than usual. It demanded an explanation. It violated expectations and was a cause for consternation.
In an interview he gave years later, he recalled telling his wife at home that “something terrible” had happened at work.
By eliminating all other possibilities, Dr. Schmidt came face to face with the discovery that has been credited with overturning many of the prevailing ideas about the evolution of the universe. He concluded that the explanation had to lie in the frequency shift caused by expansion of the universe.
He described the conclusion as startling, astounding. He recalled pacing the floor at home for hours. Applying the principle of the cosmological redshift placed the quasar at a distance more than 2 billion light-years away.
A light-year is the distance light travels in a year, moving at 186,000 miles per second. A billion light-years is an unimaginable distance. Recognizing that the quasar could be found at such a distance gave support for new ideas of the size of the universe, of how infinitely far it extended beyond our solar system and our galaxy.
In an interview with the American Institute of Physics, he recalled the trepidation he felt on coming to such a conclusion, on wondering how it would be received, if he published it, whether he might be ridiculed. “You couldn’t keep quiet, and you had to say something and it better be good because it was clear it was an occasion,” he said.
The work, published in Nature in 1963, is widely regarded as revolutionary.
In 1966, Time magazine put him on a cover and compared him with Galileo. “Just as Galileo set the stage for Sir Isaac Newton, who compiled the laws of planetary motion and gravitation,” the magazine reported, “Schmidt and his colleagues are forcing their contemporaries to exercise their inventive imaginations merely to comprehend what the great observatories have seen, and the clues collected from faint spectrograms may lead science into a new era of understanding.”
He received a major new award in science, the Kavli Prize, which honored him as one who “unlocked the gate to the far reaches of the universe.”
The prize, bestowed by the Norwegian Academy of Science and Letters, was shared with a fellow astronomer who made clear the connection between the quasar and the black hole. Scientists think that quasars harbor black holes and derive their energies from the association with black holes.
Together the concepts of the quasar and of the black hole have come to symbolize the modern view of the universe as a place of violent interactions and the unleashing of enormous energies, capable of beaming light that could reach us on Earth after a journey that consumes billions of years.
Such signals from billions of light-years away can be viewed as messages from far back in time, offering information about the early history of the universe.
Maarten Schmidt was born in Groningen, Netherlands, on Dec. 28, 1929. His father was a government accountant, and his mother was a homemaker. After spending his undergraduate years at the University of Groningen, he received a doctorate in 1956 from Leiden University, where he studied under renowned astronomer Jan Hendrik Oort. Dr. Schmidt came to the United States on a Carnegie Institution fellowship and joined the Caltech faculty in 1959. He retired in 1996.
At a party at the observatory in Leiden, he met Cornelia “Corrie” Tom, a kindergarten teacher he married in 1955. She died in 2020. Survivors include three daughters.