Johannes Geiss

2005 William Bowie Medal Winner

International Space Science Institute

Johannes Geiss was awarded the 2004 William Bowie Medal at the AGU Fall Meeting Honors Ceremony, which was held on 7 December 2005 in San Francisco, Calif.The medal recognizes outstanding contributions to fundamental geophysics and unselfish cooperation in research.


I am most pleased and honored to present this citation to Johannes Geiss, a truly great space scientist and investigator of the solar system and universe. His pioneering work, spanning over half a century, has paved the way toward understanding the physical world in which we live, its origins, and its destiny. He is a strong and effective advocate of science and ingenious in his ability to influence science policy and foster good science. Space limitations allow me to highlight only a few of Geiss’ outstanding scientific accomplishments, service to science and society, and contributions to the conduct of science.

Geiss is a world leader and foremost expert on measurements and interpretation of composition that reveals the history, present state, and future of astronomical objects. He was first to measure the composition of the solar wind noble gases in the late 1960s with his brilliant solar wind collecting foil experiments on five Apollo missions to the Moon. Many successful and innovative space experiments followed, aimed at finding the composition of matter near the Earth, of the Sun, planets, comets, and the interstellar gas.

Geiss’s leadership was crucial in the development of modern time-of-flight spectrometers capable of measuring the mass and charge compositions of space plasmas. These instruments have provided the most comprehensive record of the solar wind composition as we know it today, under all solar wind conditions, at all heliolatitudes, with profound implications for the origin of the solar wind and the composition of the Sun.

Discovery and extensive studies of interstellar pickup ions by Geiss and coworkers stimulated and revitalized theoretical work on the interstellar medium and its interaction with the heliosphere. Geiss’ discovery of the ‘inner source’ pickup ions came as a complete surprise, revealing the importance of dust near the Sun in converting solar wind ions to slow moving atoms.

Geiss has contributed many original ideas and interpretations to account for his observations. In 1972, Geiss and Hubert Reeves found the deuterium abundance in the protosolar cloud, using the newly measured solar and meteoritic abundance of helium-3. Later, using measurements of solar and interstellar helium-3, Geiss showed that the deuterium plus helium-3 to hydrogen ratio remained surprisingly constant over the lifetime of the universe, and placed limits on its baryonic density. Most recently, he proposed a galactic mixing model, involving infall of gas from dwarf galaxies to explain the puzzling low metallicity of galactic gas.

As impressive as Geiss’s contributions are to fundamental science, he unselfishly promotes science and is an able spokesman for the societal benefits of scientific research. He was among the key players shaping the science policy and current science program of the European Space Agency. He is a strong advocate for international scientific cooperation and successfully promoted international space missions such as Ulysses, SOHO, and Cassini/Huygens. He is largely responsible for the excellent space science program in Switzerland.

Perhaps Geiss’s most important contribution to the conduct of science came late in his career through his creation and leadership of the International Space Science Institute (ISSI).Today, ISSI is flourishing and is the leading place for topical international space science workshops and team meetings, bringing together scientists from around the world.

Geiss, a pioneering space physicist, is a modest person who freely shares his knowledge and ideas with colleagues, and is most stimulating to interact with. He is devoted to science and its conduct and promotion. He truly epitomizes all those qualities that the William Bowie Medal honors.

—GEORGE GLOECKER, University of Maryland, College Park


Thank you very much, George, for this generous citation.

After receiving my master’s degree in physics at Göttingen University (Germany), I joined Wolfgang Paul’s group and did a Ph.D. thesis on natural variations in the isotopic composition of lead. Later, I brought one of our instruments to Bern (Switzerland) and built up a mass spectrometer laboratory in Fritz Houtermans’ Physics Institute. We investigated, with the help of excellent students, lead isotope variations from the oldest African ores to the lead deposits that were forming in the volcanic region of southern Italy. Soon our group became a known entity in the emerging field of ‘nuclear geology.’

In 1955, Harold Urey at the University of Chicago invited me to work with him on meteorites. This was still a few years before Sputnik, and meteorites were unique messengers from the outside world. I measured argon-potassium ages of a variety of meteorites. The achondrite Shergotti gave an exceptionally low age, so low it could hardly be a piece of an asteroid. Much later, it became clear that Shergotti is a Mars meteorite and indeed the youngest of them all.

In Chicago, Carmen [my wife] and I renewed old friendships and made new friends. From Urey and Edward Anders I learned much about cosmic abundances, Friedrich Begemann and I studied exposure ages of meteorites, and with Cesare Emiliani I went, a few years later, to Miami, where we started a paleotemperature laboratory. There I was reminded of my childhood south of the Baltic Sea, where the landscape with its dunes, hills, and lakes was formed during the Ice Ages. And now, sitting here in hot Florida, I was trying to find out from Caribbean foraminifera, why and when the Scandinavian ice advanced and retreated.

In the mid-1960s I took charge of the Physics Institute in Bern and, with Peter Eberhardt and Norbert Grögler, built up a laboratory for extraterrestrial research, starting with investigations of meteorites and lunar samples. I went to the NASA Center in Houston in the fall of 1968, taking along the Solar Wind Composition device we had developed in Bern. Supported by Bill Hess and his associates, the Swiss experiment was included in the Apollo 11 and later Apollo payloads. The success of our Apollo experiments established the Physics Institute as a space research center. Participation in many European Space Agency (ESA) and NASA missions followed, and this has been continuing very successfully with younger people and new projects. The creation of ISSI has further strengthened Bern’s position in space science. Many Swiss helped start ISSI. But equally important was the international recognition and support offered by Reimar Lüst, Roger Bonnet, David Southwood, and Martin Huber of ESA, Bengt Hultqvist of Sweden, Len Fisk and Wes Huntress of NASA, and Roald Sagdeev of the Russian Academy.

In the1970s, George Gloeckler invented a new type of mass spectrometer, combining time-of-flight measurement with preacceleration. This has revolutionized plasma composition measurement in space. We in Bern were fortunate to join him on the SWICS-Ulysses experiment that for 15 years has provided us with a unique three-dimensional picture of heliospheric ion populations. I am looking forward to continuing this marvelous cooperation.

I am very grateful to receive the William Bowie Medal from the AGU, the world’s strongest union of Earth and solar system scientists. Since the time of my thesis, our understanding of the Earth and the solar system has greatly advanced. Much of this affects society directly. Wisely applied, the new insights will help to minimize natural and man-made disasters, and to develop balanced space programs that advance science and serve society.

—JOHANNES GEISS, International Space Science Institute, Bern, Switzerland