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Maarten Schmidt, Caltech astronomer who changed our understanding of the cosmos, dies

Maarten Schmidt, the Dutch-born American astronomer whose discovery of quasars dramatically changed our understanding of the evolution of the cosmos and revealed the might and power of the beasts that roam space, has died at his home in Fresno.

Schmidt, professor emeritus at Caltech, died Saturday at the age of 92.

Schmidt had only recently arrived at Caltech, when he climbed into the viewing cage of the great Palomar Mountain Telescope to try to understand the measurements radio astronomers were getting of a bizarre object that should have been a star but couldn’t be .

The object, known in flimsy astronomy as 3C273, was 3 billion light-years away, a good way back to the Big Bang. And yet it was a hundred times brighter than our own galaxy of 100 billion stars. Even stranger, when Schmidt finally obtained a spectrum of his light signature, it looked like nothing he’d seen before.

After weeks of fruitless puzzling, Schmidt told his wife Corrie, “Something terrible happened in the office.”

Turns out it wasn’t that bad. Maarten Schmidt had discovered the quasar (quasi-stellar radio source), a machine of incredible power. So incredible that it took another six years for Donald Lynden-Bell, one of Schmidt’s students, to come up with the explanation: a hungry black hole eating a meal. Nothing can escape a black hole’s fearsome gravitational pull, but material at the edge of its churning vortex becomes so superheated that blasts of energy are blasted out at nearly the speed of light.

This explosion of energy was recorded by radio telescopes on Earth. It wasn’t a galaxy, and it wasn’t a star or even a black hole properly. It was the radiation emitted by the greatest show in the universe.

The discovery made Schmidt famous. His square, bespectacled face appeared on the cover of Time Magazine. Awards flowed towards him. And unlike some discoveries of oddities in space, the importance of Schmidt’s work only grew with time, as cosmologists recognized the role quasars played in the construction of the modern universe.

“The discovery of quasars is one of the fundamental discoveries in astrophysics and has completely transformed astronomy,” said George Djorgovski, professor of astronomy and director of the Center for Data Driven Discovery at Caltech. Black holes have been a theoretical concept for some time, but quasars have provided concrete evidence of their existence. They would play a role in everything from proving the existence of dark matter to the formation of galaxies.

In 2008, more than four decades after its discovery, Schmidt and Lynden-Bell received the $1 million Kavli Astrophysics Prize for their work that “drastically expands the extent of the observable universe and adds to our contemporary view of the violent universe.” in which it is massive Black holes play a key role.”

The son of a government accountant, Schmidt was born on December 28, 1929 in Groninge, Netherlands. At age 12, he built his first telescope using a lens he found on his grandfather’s farm. He was still a student at the University of Groningen when he caught the eye of the country’s leading astronomer, Jan Oort, who gave his name to the Oort cometary cloud that surrounds the solar system.

Oort had Schmidt work at Leiden University’s observatory, the oldest in the world that measures the brightness of comets. But it was his other early work, studying the spectroscopic fingerprint of hydrogen, that would prove crucial a decade later when he discovered an object that made a supernova look like a child’s pistol.

Schmidt’s reputation for demanding tenacity eventually drew the attention of astronomers at Mt. Wilson and Palomar Observatories in Southern California. At the time, these observatories boasted the largest collection of star surveyors in the world, from Walter Baade, who doubled the known size of the universe, to Fritz Zwicky, who predicted the existence of dark matter.

When Schmidt joined them in 1959, an important instrument was revolutionizing astronomy, the radio telescope. For millennia, visible light was the only medium by which humans understood what was happening beyond Earth. But electromagnetic waves come in all sizes, from the shortest wavelengths and highest frequencies—strong gamma rays and X-rays—through ultraviolet, visible, infrared, microwave, and finally low-frequency radio waves.

Radio waves are much longer than light waves, ranging from centimeters to kilometers, which is why radio telescopes have to be very large. That can be a problem, but a radio telescope has key advantages, including the ability to see through interstellar dust that would block shorter-wavelength radiation. This meant that radio telescopes could probe extremely distant regions of the universe.

In 1961, Schmidt was finally given the chance to operate the great 200-inch telescope at Palomar, an instrument so magnificent that the greatest astronomers waited months and years for an opportunity to use it. Schmidt’s job was to track down some strange objects that were spotted by radio telescopes. A time-consuming, arduous task, but one for which the patient young astronomer was well suited.

“It was romantic!” he later told an interviewer. “Sometimes you just had to stop and look around.”

Most of the radio sources turned out to be ordinary elliptical galaxies. But some were puzzling. They didn’t look like galaxies at all. Instead they looked very much like stars. Very strong stars. He was particularly interested in 3C273, which radio astronomers in Australia had sufficiently narrowed down to a region of the sky that Schmidt thought he could capture near Palomar. In late December 1962, just weeks after the Cuban Missile Crisis had brought the world to the brink of nuclear annihilation, Schmidt finally succeeded. But that didn’t solve the mystery. In fact, it’s only just getting started.

The mysterious 3C273 turned out to be two sources, a star and an attached jet of gaseous material. The spectra he got on his photo plates made no sense. The emission lines on the spectrogram didn’t match anything he knew.

A few weeks later, Schmidt was sitting in his office on the second floor of Caltech’s Robinson Building when it clicked. Suddenly he realized that the image looked very much like the fingerprint of hydrogen, the main fuel in stars. Except it was hugely redshifted, meaning the object was moving away from Earth at an amazing speed of almost 30,000 miles per second and was fantastically far away.

Still, it was brighter than most of the nearby galaxies. If it was so far away, how could you even see it? It shone in the light of 2 trillion stars but was only about the size of our solar system, less than a light-year across, while the Milky Way is 100,000 light-years across. What happened?

Schmidt still wasn’t sure if he was looking at something much closer in our own galaxy, and therefore much less interesting, when he went to a colleague who was puzzling over a similar object. It had the same telltale signature and was even more redshifted, meaning it was even further away. That was the aha moment.

In March 1964, Schmidt became instant scientific celebrity when he and his colleagues published four now-classic papers describing what Schmidt called quasi-stellar radio sources. It took some time for the scientific community to accept the term quasars.

In a 2014 interview, Schmidt recalled the excitement surrounding his discovery. It was all very flattering and not least good for his career. In 1975 he became chairman of the Department of Physics, Mathematics and Astronomy at Caltech and then director of the Hale Observatories, which operated the Palomar and Mt. Wilson instruments.

“It was a great event,” said Schmidt. “But when it’s done, it’s done.”

The more satisfying work came later, when he was able to show where quasars fit on the universe’s timeline. As some of the most distant objects that can be studied, and therefore the oldest, “they show a snapshot of what the universe looked like at the time,” he said. “I was able to collect evidence about the early development of the universe.”

According to Djorgovski, they provided the first clues to the so-called reionization epoch of the early universe, when stars and galaxies first began to form. “It was one of the great steps in the evolution of the universe,” Djorgovski added.

Quasars turned out to be cosmic dinosaurs, ancient beasts that roamed the landscape of space, preying on weaker creatures to sate their vast appetites. Along with the discovery of the cosmic microwave background, this proved to be the final nail in the coffin for the so-called steady-state theory of the universe, which claimed that the universe had always been like this and always would be like that.

These relics of an ancient cosmos, so fantastically distant and so different from anything being created in space today, were evidence that the young universe was a very different place.

It is now believed that there are supermassive black holes at the center of most large galaxies, such as the Milky Way. But relatively few today have quasars or what are now called active galactic nuclei. They are active because they eat. Over time, the vast majority of black holes consume all of the dust and gas and other things in their region and go into hibernation.

The black hole at the center of the Milky Way known as Sagittarius A*, is one of them. In the future, however, his appetite will awaken. The nearest large galaxy, Andromeda, is steadily approaching the fringes of the Milky Way. The two giants will collide in about 4 billion years.

This event will wash tides of gas and dust onto the deadly black hole shoreline in both galaxies. It’s supposed to be an amazing show, but no one on earth is going to see it. By then the sun will be bloated and reddened, making our planet uninhabitable.

After touching fame, Schmidt served as President of the prestigious American Astronomical Society for two years. In addition to the Kavli Prize, he won the Gold Medal of the Royal Astronomical Society in 1980 and the James Craig Watson Medal in 1991.

Schmidt was married to Cornelia “Corrie” Schmidt-Tom for 64 years until her death in 2020. He leaves behind his three daughters Anne, Marijke and Elizabeth.

Johnson is a former Times contributor.

https://www.latimes.com/obituaries/story/2022-09-23/maarten-schmidt-astronomer-who-changed-our-understanding-of-the-cosmos-dies Maarten Schmidt, Caltech astronomer who changed our understanding of the cosmos, dies

Russell Falcon

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