Gerard Kuiper (1905 – 1973)

Astronomer - Lunar and Planetary Laboratory

Gerard Kuiper, the astronomer for whom the Kuiper Belt beyond Neptune is named, died on Dec. 23, 1973.

Gerard Kuiper (1905 - 1973) is regarded by many as the father of modern planetary science. He is well known for his many discoveries, including:

  • 1947: He correctly predicted carbon dioxide is a major component of the atmosphere of Mars.
  • 1947: He correctly predicted the rings of Saturn are composed of particles of ice.
  • 1947: He discovered Miranda, the fifth moon of Uranus.
  • 1949: He discovered the moon Nereid orbiting Neptune.
  • 1949: He proposed an influential theory of the origin of our solar system, suggesting the planets had formed by the condensation of a large cloud of gas around the Sun.
  • 1951: He proposed the existence of what is now called the Kuiper Belt, a disk-shaped region of icy objects outside the orbit of Neptune, a region that produces many comets.
  • 1956: He proved that Mars' polar icecaps are composed of frozen water and not of carbon dioxide as they had been previously assumed.
  • 1964: He predicted what the surface of the Moon would be like to walk on—"like crunchy snow". This was verified by astronaut Neil Armstrong in 1969.

"Kuiper studied the planets... at a time when they were scarcely of interest to other astronomers," said Bill McKinnon, a co-investigator on the New Horizons mission to explore the Kuiper Belt, the region of space named in Kuiper's honor. "But with new telescopes and instrumentation, he showed that there were great things to discover, which is as true today as it was then."

Gerard played an influential role in the development of infrared airborne astronomy in the 1960s and 1970s. In 1967 the NASA four engine jet Convair 990 aircraft with an onboard telescope became available for infrared studies at an altitude of 40,000 feet. Gerard used it extensively for spectroscopy of the sun, stars, and planets, discovering things about them that could not be found from ground-based observatories. The Kuiper Airborne Observatory (1974) was named in his honor, as were craters on the Moon,Mercury and Mars.

Gerard was a demanding individual whose routine included hard work and long hours.

"He worked extremely hard himself, and he demanded the same dedication, devotion and seriousness from everybody around him," said scientist Dale Cruikshank. "If they didn't give that, or if they didn't perform, they ran afoul of him. That applied to students. It also applied to fellow faculty, technical associates and engineers -- anybody around him. But at the same time, he had a humorous side, a warm side, a personal side that was in some ways appealing."

One hundred years after Gerard's birth, the New Horizons mission is exploring the Kuiper Belt region of our solar system.

"Kuiper was one of the first scientists to focus almost exclusively on exploring the properties of planets," said Dr. Richard Binzel, New Horizons co-investigator and professor at the Massachusetts Institute of Technology (MIT). "His work laid the foundation for the spacecraft missions of the late 20th and early 21st centuries."

Gerard was born in the Netherlands in 1905 and was educated at Leiden University as an astronomer with a doctoral dissertation on binary stars. Gerard came to the United States in 1933 and obtained American citizenship in 1937.

He worked at Lick Observatory, Harvard, Yerkes Observatory of the University of Chicago and the University of Arizona. The Lunar and Planetary Laboratory, a research and educational unit in which many planetary scientists have been trained, was established under his guidance at the University of Arizona.

Gerard died in 1973 from a heart attack while on vacation in Mexico with his wife, Sarah Fuller. He was 68.

Remembrances from the Lunar and Planetary Laboratory

Dale Cruikshank

He was a very, very demanding individual. He worked extremely hard himself, and he demanded the same dedication, devotion and seriousness from everybody around him. If they didn't give that, if they didn't perform, then they ran afoul of him. That applied to students; that applied to fellow faculty, technical associates, engineers, anybody around him.

At the same time he had a humorous side, a warm side, a personal side that was in some ways appealing. But he was very difficult to work for, or even in the same building with. He prided himself on knowing almost everything, or having access to people who did. There's funny things that linger on even in the new building over here. The entrance door on the side is always locked. I assume it's still locked. It certainly was from the get-go with him because he didn't want "common people" trafficking through his new building, and he would put it exactly that way: This is only for serious people who are doing what we're doing here, which is very serious, and everybody else, the public, just stay away.

George Coyne

He was undoubtedly a great scientist. He was very, for want of a better word, authoritarian. He was of the European school of "the professor says, and the students do what the professor says" kind of thing. Though he loosened up quite a bit, I think.

He was not the easiest man to get along with. But he wished everybody well. I'll never forget one incident where a Polish astronomer had to leave Poland because the Russians were after him, or something or other. He came on a visit and then he had to go back. Gerard Kuiper set up a deal with him whereby if he sent a colored postcard, Kuiper had a position for him, a permanent position. If he sent just a black-and-white postcard, unfortunately that meant that he didn't have a position for him. Kuiper worked very hard to get this [position opened]. I worked with the guy for many years: Wieslaw Wisniewski.

So that was the kind of guy Kuiper was. Just those incidents describe him. He had to be very strong. He was starting a major effort here at the University of Arizona, so he had to kind of dominate the scene; and he attracted very good people.

Alan Binder

There were only a handful of us, and one of the reasons I believe was very few people could tolerate being with Kuiper. Carl Sagan, Dale Cruikshank, Bill Hartmann, me, Toby Owen-there's less than a dozen people who can say, "I studied under Kuiper." To me, it's all a matter of Darwinian evolution: Either you could stand being under him, or you couldn't. Very few people really could.

Kuiper had very little interest in our education. We were there to work as assistants, and that's what we learned. We had 20-hour assistantships, and he would bawl us out if we worked less than 40 hours, saying we weren't taking our assistantships seriously. When he taught the few courses he did, he would be up there: "How much longer do I have to be here?" He did not like to teach. He did research, and anything that got in his way, he didn't want to do.

Dale and I worked in the infrared spectrometer lab; we built spectrometers and went on these two-week long observing runs three times a year, so you see how much time we spent away from class-and that was it. We learned by doing, and by listening to him. When you're on the observatory floor all night-and of course nowadays they don't do that, astronomers sit at home with their computer and they don't go up there-in my day I sat out there in the freezing night all night, and helped Kuiper, or did my own observations, later in my career. So you learned by being around Kuiper, not by formally having coursework and things like that. I would say, people who worked with Tom Gehrels had a different relationship, but those of us who were with Kuiper, it was pretty much that. You were on your own. You survived, or you didn't.

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