Fred Lawrence Whipple (1906–2004)
Received 2005 August 13; accepted 2005 August 16; published 2005 November 18
The passing of Fred Lawrence Whipple in his 98th year on 2004 August 30 brought to an end a career that was principally, though far from exclusively, dedicated to an understanding of the smaller members of the solar system and their role in its evolution. In this area alone he was a dominant influence for an unprecedented three‐quarters of a century, while his roles in the development of the space program and in the conversion of the Smithsonian Astrophysical Observatory from obscurity to one of the world’s leading organizations in our science are equally remarkable.
Fig. 1.— A 1968 photograph of Fred Whipple, taken by his wife, Babette. The cartoon on the wall was drawn by Don Menzel to honor Fred's 60th birthday on 1966 November 5. Note the way “60” is worked into the illustration of Fred racing along on his bicycle.
Fred Whipple was born into a farming family in Red Oak, in the southwestern corner of Iowa, on 1906 November 5. His father, Harry Lawrence Whipple, was of English stock, the Whipples having lived in North America since the early 17th century. The forebears of his mother, Celeste MacFarland Whipple, were from Scotland and protestant Ireland. Both parents were active in the local Presbyterian church, with Harry serving as an elder. Fred was effectively their only child, as a brother 2 years younger died of scarlet fever when Fred was 4. Around that same time, Fred developed polio, the effects of which prevented him from pursuing a dream of becoming a top‐notch tennis player. Early on, he took an avid interest in reading science fiction, as well as in trying to understand mechanical systems and the workings of various types of machinery, of which early 20th century life on a farm provided a surfeit. This rather set him apart from the other local children, and although he has described his father as a highly intelligent man who could have benefited immensely from higher education, his father’s interests were directed more toward history than toward science. Fred’s preparation for his eventual career was therefore rather left to develop on its own.
Anticipating the drop in corn prices, Fred's father sold the farm, and in January 1922 the family embarked on the long journey to Long Beach, California, where there were already several other family members and an extensive community of Iowans. Fred's father bought and operated a grocery store, while Fred, then in the middle of his junior year, entered the Long Beach Polytechnic High School. There he continued to excel at mathematics and could for the first time also take a physics course.
As his high school days ended, the family’s Presbyterian connection dictated that Fred should attend Occidental College in Los Angeles—although he was expected to help out in the grocery store on Saturdays. One semester at “Oxy” was more than sufficient to convince him that his own mathematical knowledge was at a substantially higher level than was being taught there, so in January 1924 he transferred to the University of California at Los Angeles. Although the standard of mathematics teaching there met with his approval—it was the subject in which he was majoring when he received his undergraduate degree in 1927—Fred began to realize that he found mathematics too boring to consider for an eventual career. It is therefore fortunate that during his junior year at UCLA, he took a course in astronomy taught by Frederick C. Leonard, who encouraged him to pursue that field instead. There was at that time no degree program in astronomy at UCLA, so Leonard used his connections to recommend Fred for a teaching fellowship that allowed him to enter the graduate program in astronomy at the University of California at Berkeley.
At Berkeley, Fred came principally under the influence of the astronomy department’s director, Armin O. Leuschner, who soon inspired in him a lifelong interest in the computation of orbits. In those days, of course, the computation of the orbit of a new comet was a lengthy process involving several hours of work using logarithms or a mechanical calculating machine. (The author, who followed Fred by some 30 years with a similar interest in the computation of cometary orbits by hand, together with an undergraduate degree and the rejection of a career in mathematics, understands this all too well!) Fred’s first published orbital computation, soon after the discovery of the object in November 1927, involved the comet now known as 29P/Schwassmann‐Wachmann, which was the first comet found to be confined to the region between Jupiter and Saturn and therefore to be observable all around its orbit.
Following the Lowell Observatory’s March 1930 announcement of the discovery of Pluto several weeks earlier, Fred and fellow Berkeley student Ernest C. Bower worked “under the general direction of Professor A. O. Leuschner” on calculating its orbit. Although stymied by the unavailability of the Lowell observations, they were able to acquire a 19 day span of observations from the Yerkes and Lick Observatories and thereby be the first to publish any orbital calculations. Having established that Pluto had “a fairly well determined distance from the Earth of approximately forty one astronomical units” (a distance that was indeed exactly correct 1 week into the span), they could define Pluto’s orbital plane rather well, but also wisely state that “no definite conclusion concerning the eccentricity and period can be drawn.” Their demonstration that solutions “from a near circle to a parabola” fitted the observations contrasted sharply with the Lowell Observatory’s own first orbit computation, published a whole week later using observations over a 59 day arc, which gave an orbital eccentricity of 0.909 and a period of 3190 yr, which are decidedly incorrect.
Interestingly, Leuschner—whom Fred described to me 5 years ago as not so much applying direction as being “the one who spoke to the press”—then immediately publicized this Lowell computation, perhaps deliberately to play down any thought that Pluto bore a resemblance to the planet predicted by that observatory’s founder. Leuschner averred that among various other possibilities, “it may be one of many long‐period objects yet to be discovered.” Furthermore, Fred’s UCLA mentor Leonard wrote in the August 1930 ASP Leaflet—after Pluto’s 0.25 eccentricity had been established—to the effect that given the “zones” of terrestrial, minor, and giant planets, Pluto was perhaps the “first of a series of ultra‐Neptunian bodies, the remaining members of which still await discovery.”
The other principal influence on Fred at Berkeley was Donald H. Menzel, an occasional visitor from Lick who was only 5 years older than Fred and essentially the only astrophysicist on the staff. Fred chose Don to be his thesis advisor, and both Don and his wife, Florence, befriended Fred and his first wife, Dorothy Woods (to whom he was married from 1928 to 1935), a particularly welcome gesture when Fred was at Lick during August–October 1930, making observations and during subsequent months analyzing them and completing his thesis. (Fred is surely not unusual in experiencing nausea during the drive up and down Mount Hamilton. He discovered that a good drink when he hit the bottom of the road would clear his head, but—of course—he did not know this during those Prohibition days.)
Fred’s thesis, “A Spectrophotometric Study of the Cepheid Variables η Aquilae and δ Cephei,” involved the acquisition and measurement of line contours in the 391–435 nm region from three‐prism spectrograms with the 0.91 m refractor, as well as the monochromatic light curves of the continuum at four wavelengths in the 405–600 nm region from two‐prism slitless spectrograms with the 0.91 m reflector. Using Planck’s radiation law, it was then possible to derive the temperatures corresponding to maximum and minimum light. In principle, the relative changes in radius then followed from the light variations and the temperatures, and the use of radial velocity data allowed these to be converted to absolute radii and hence to yield absolute magnitudes and parallaxes. But the parallaxes Fred obtained in this manner were some 3 times larger than those given by the Cepheid period‐luminosity law. As a mathematician, and also—mindful of his days on the Iowa farm—as an engineer, he was happy with the manner in which he had worked the equations and the numbers, as well as with the observations themselves. He also wanted to find out something about the stars. But what he actually found was that the astrophysical theory had to be wrong. As he later put it, this simply disgusted him, and he therefore could never summon any interest in pursuing possible modifications to the theory.
On receiving his Ph.D. degree in mid‐1931, Fred was faced with the choice of staying at Lick as an observer—and perhaps thereby becoming “a big frog in a little pond”—or of accepting Harlow Shapley’s invitation to become the inverse. His Iowan instinct was for the inverse, and accordingly, he traveled eastward to head the observing program at the Harvard College Observatory (HCO), where he arrived on Friday, 11 September 1931. At that time, the HCO was in the process of setting up its new Oak Ridge observing station in the town of Harvard, Massachusetts, some 40 km west of the headquarters in light‐polluted Cambridge. In addition to the acquisition of a new 1.5 m reflector, this involved Fred in moving four patrol cameras and several other telescopes from Cambridge and getting and maintaining them in proper alignment. This maintaining of alignment required regular examination of the patrol plates for image quality. Such repetitive examination is conducive to the discovery of transient objects, and in August 1932 Fred discovered the first of the six comets he found over the course of the next decade. Although the many asteroids on the plates were routinely ignored, he recognized one in February 1933 as having an unusually high orbital inclination, and it eventually became (1252) Celestia, which he named in honor of his mother. In December 1939 he discovered a ninth‐magnitude nova (now BT Mon) on a spectrum plate taken by Bart Bok with the Metcalf 0.46 m refractor.
During Fred’s first couple of years at Harvard, he became interested in studying galaxies. From exposures with the Metcalf 0.30 m refractor using plates that were sensitive in various color bands—notably some specially acquired fast plates in the red—he published color indices for 38 galaxies in the Coma‐Virgo region, confirming an earlier suggestion that galaxies were redder than average stars of corresponding spectral type. He wanted to pursue this result in order to examine the possibility of a distribution of different populations of stars in galaxies (something Walter Baade was also just starting to think about at the time), but was quickly made to realize that Shapley did not welcome competition in galactic studies. Although Fred was happy enough to observe and otherwise to study variable stars (he wrote a number of papers with Cecilia Payne‐Gaposchkin on the 1935 nova DQ Herculis, and he was particularly proud of his collaboration with Jesse Greenstein in writing a 1937 paper explaining Jansky's early dekameter radio observations), he began to appreciate that his career might advance more successfully if he were to concentrate on investigating celestial objects that were very much closer.
One scientist for whom Fred always had enormous admiration was Ernst Öpik, who was a visiting astronomer at Harvard during the early 1930s. In a paper written at that time, Öpik anticipated many of the thoughts developed by Jan Oort some two decades later, namely, the idea that a cloud of comets and their associated meteoric debris extending out to perhaps a parsec from the Sun could have largely survived the passage of stars nearby during the lifetime of the solar system. Öpik’s extension of this idea to the possibility of similar clouds around other stars led Fred to speculate that some of the so‐called sporadic meteors might belong to such a cloud surrounding Sirius. This would of course have required that these meteors have hyperbolic orbits with respect to the Sun. Öpik was a firm believer in hyperbolic meteors, particularly after his statistical analysis of simultaneous visual observations of meteors from sites 40 km apart under the darker and clearer skies of Arizona during an expedition there by a Harvard team showed some 60% of the orbits to be hyperbolic. Since others had strongly criticized the concept of hyperbolic meteors, Fred’s admiration for Öpik’s work inspired him to undertake a similar investigation using meteors observed from Cambridge and Oak Ridge during 1936–1937, except that he obtained greater measurement accuracy by making the observations photographically—a technique applied three decades earlier by W. J. Elkin at Yale, but over a baseline that was too short to give satisfactory results. Although Fred appreciated that his own project suffered from the drawback that the computed orbits depended on when the meteors actually appeared during exposures lasting an hour and more, the fact that none of the four sporadic meteors in the data set yielded consistently hyperbolic solutions for all assumed times dampened his earlier enthusiasm that such meteors exist in significant numbers.
Fred’s continuing work with the Harvard Photographic Meteor Program soon led to his determination of elliptical orbits for individual meteors in the Geminid and Perseid streams, and his recognition that the Taurid meteor stream is associated with Encke’s comet. During the 1940s, James G. Baker devised the “super‐Schmidt,” an f/0.85 camera with an aperture of 31 cm and a 52° diameter field that would revolutionize the meteor studies. With the help of Harlan J. Smith and Richard E. McCrosky, pairs of cameras were erected at mobile sites in New Mexico in 1948. Gerald Hawkins, Luigi Jacchia, Annette Posen, Richard Southworth, and Frances Wright participated in the analysis. Fred was also eager to supplement the photographic work with detections of meteors by radio, and the Harvard Radio Meteor Program was established in 1955 with the help of Hawkins and Curt Hemenway.
Fred’s own interest in meteor studies, however, was moving in the direction of what could be learned from meteors about the Earth’s upper atmosphere. This interest was apparent in papers he wrote as early as 1939, and it played a role in the selection of the New Mexico sites for the photographic program. Wernher von Braun and his associates, not to mention supplies of captured V‐2 rockets, were relocated at the nearby White Sands Proving Ground immediately after World War II, and rockets reentering the Earth’s atmosphere effectively become artificial meteors.
Or, almost, because natural meteors arise from the ablation of cometary meteoroids that have much lower strength and density than a rocket casing. It was his appreciation that a tiny rotating meteoroid heated by friction in the atmosphere experiences jet‐type bursts as it disintegrates that gave Fred his single most important scientific idea, namely, that a whole comet works in much the same way. If the comet has a nucleus some kilometers across that consists of meteoroidal material frozen in a mixture of ices such as H2O, CO2, NH3, and CH4, with solar radiation providing the heating, not only would the comet experience a reactive jet force arising from the ejection of meteoroidal material released as the ices vaporize, but the photodissociation of the ices (as first proposed by Pol Swings) could account for the emissions of radicals such as the OH, CO, NH, and CH observed in cometary spectra. Furthermore, while the force would basically give the comet a nongravitational push radially outward from the Sun, there would likely be a lag in the transfer of heat, and the rotation of the nucleus would therefore also provide a transverse component. As Fred noted with particular reference to his beloved Encke’s comet, the transverse component could then be responsible for the fact that this comet returns to perihelion progressively earlier by a few hours each revolution, whereas comets rotating in the opposite sense would instead be delayed. The 1950 paper in which Fred published his icy‐conglomerate, or “dirty snowball,” cometary model has been ranked among the 53 most significant papers published in the Astrophysical Journal or Astronomical Journal during the 20th century.
Fred’s contribution to the war effort was the co‐invention of a technique—essentially a type of lawn mower—for chopping a sheet of aluminum foil into a large number of pieces. Even a single aircraft could drop enough of this “chaff” to confuse German radar operators into thinking they were being attacked by hundreds more. Each piece of chaff acted as a half‐wave dipole, provided one knew the frequency band being used for the radar, which could be established using a radio receiver in the aircraft. Fred spent some time in Europe with the US and UK military on this effort, and in 1948 he received a Certificate of Merit from President Truman. A peacetime invention of Fred’s for the military was the “Meteor bumper,” which consisted of a second, outer skin for a spacecraft. This would bear the brunt of a typical micrometeorite impact and protect the inner skin, which would be separated from it by a couple of centimeters. His insight regarding the future development of space flight is underscored by the fact that he wrote up this idea as early as 1947.
In 1952 he teamed up with von Braun to write a popular article for Collier’s about a first manned exploration of the Moon. Their estimate that this could happen within 25 years was handsomely met in reality with 8 years to spare. In another Collier’s article in the same year, he described the revolution astronomers would experience by having a telescope in space. Here reality took a while longer to catch up, but his thoughts about monitoring the Sun at ultraviolet and X‐ray wavelengths and analyzing “the great dust and gas clouds of the Milky Way, where stars are born” were remarkably prescient.
In June 1954 Fred was the only astronomer to participate in a high‐level meeting at the Office of Naval Research at which tentative plans were discussed for a US satellite. This led to the “Project Orbiter” concept, chaired by Fred, and the announcement by President Eisenhower in July 1955 that the US would indeed launch a satellite during the upcoming international geophysical year (IGY). Sadly, that task was assigned to a rival team that was far behind in rocket‐launching capability, whereas the fourth stage of a launch by members of the by‐then‐defunct Project Orbiter team in September 1956 really might have sent a satellite into orbit, had that stage not deliberately been a dummy.
July 1955 was also the month in which Fred became director of the Smithsonian Astrophysical Observatory (SAO). This came about following a meeting between Fred’s old friend Don Menzel (who had followed Fred to Harvard in 1932 and who in 1952 had succeeded Shapley as HCO director) and Leonard Carmichael, then the secretary of the Smithsonian Institution. The retirement of Loyal Aldrich as SAO director in 1954 created a problem for Carmichael, because the Observatory, then located among the Smithsonian’s museums in downtown Washington, was in such a moribund state that he had been unable to entice any suitable successor. Carmichael knew that the only way to revitalize SAO was by introducing new research programs, and it occurred to Menzel that if SAO were to move to Massachusetts, there could be tremendous advantages to both the Smithsonian and Harvard. A full professor at Harvard since 1950, as well as then chairman of the Department of Astronomy, Fred was an obvious candidate for the Smithsonian position, and the proposed move became reality.
Given his interest in the plans for a US satellite, Fred had already recognized the need to develop a capability for tracking it, and the responsibility for this work, together with the necessary funding, was soon awarded to SAO. The super‐Schmidt designed for the earlier meteor work needed further modification for this purpose, and Baker worked with Perkin‐Elmer’s Joseph Nunn to produce a new camera that could photograph on a narrow roll of film the background stars and the satellite as it moved up to 30° across the sky. These Baker‐Nunn cameras were erected at 12 observing stations around the world, each largely operated by local staff. But the ambitious construction effort involved (not to mention the political effort of making arrangements with 10 other countries) would take a few years, and the IGY was to start in July 1957. Fred appreciated that it would therefore also be necessary to develop a system for tracking the satellites visually.
To this end, and contrary to the ideas of the military folk associated with the plans for a satellite, he appealed to amateur astronomers and other volunteers to form international “Moonwatch” teams. Eventually, there were more than 200 of these groups of typically a dozen observers armed with standard telescopes and star charts—and, in particular, a member who would accurately record the times of the satellite sightings. Accordingly, just 5 days after the Soviet Union startled the world with the launch of Sputnik 1 in October 1957, SAO scientists were able to announce the first Western computation of its orbit, based mainly on Moonwatch visual observations. “Startled” might be a rather strong word to apply with regard to Fred’s own expectations. A year earlier, he had written in The Saturday Review: “Some Westerners suspect that Moscow will try to get a satellite aloft before we do. American scientists are bound to be disappointed if that happens. But we won’t be belligerent about it. Although the type of rocket that can place a moon in its orbit is practically an intercontinental missile, the science that goes into IGY is dedicated to peace… It might be good for all of us if some of the natural competition between East and West could be spent in such useful but harmless moon sport.” Fred was also quick to appreciate that both Sputnik 1 and Sputnik 2 (launched in November 1957) were significantly affected by atmospheric drag, even at heights of 300 km and more, and that satellites would therefore become excellent probes of density and temperature in the upper atmosphere.
While Moonwatch was still providing useful results into the 1960s on the numerous Soviet and American satellites that had been launched by then, the Baker‐Nunn cameras soon became the mainstay of the SAO satellite‐tracking program, perhaps the principal outcome of which was the publication of the “SAO Standard Earth.” This made use of many tens of thousands of observations of satellites in order to produce a detailed study of the figure of the Earth and to improve the determination of intercontinental distances by an order of magnitude. In June 1963, Fred received from President Kennedy the Award for Distinguished Public Service, the highest civilian honor for a government employee. This recognized his role in designing and establishing the observing program “which stood ready to track the first artificial satellite and has since provided valuable scientific data concerning the nature of the Earth, its atmosphere, and outer space.” Following the introduction a few years later of lasers for ranging to satellites from the Baker‐Nunn stations, an improvement by another order of magnitude was achieved, yielding intercontinental distances good to just a few meters.
Ever since its founding, SAO had lacked a “real” observatory. By the mid‐1960s, Fred was contemplating the construction of a serious observational facility on Mount Hopkins, south of Tucson, in collaboration with the University of Arizona. An instrument for detecting γ‐rays by Cerenkov radiation was installed there in 1968, and this was followed by a Baker‐Nunn camera and a laser for satellite tracking. In 1970 the 1.5 m Tillinghast reflector was established, and this is still the principal workhorse at the Mount Hopkins site for spectroscopic work. This instrument was named for SAO’s talented director for administration, Carl W. Tillinghast, who had died from cancer at the age of 36 the previous year.
But Fred wanted to equip the site with a telescope that would rank among the world’s largest. Inspired by the fact that the γ‐ray telescope made use of 250 small mirrors, he recognized that the use of multiple mirrors would greatly reduce the cost of what could therefore effectively be a large telescope. With the help of Aden Meinel at the University of Arizona, he acquired several lightweight 1.8 m mirror blanks from the US Air Force and worked actively on the telescope’s design. When it was finally dedicated in 1979, 6 years after Fred’s retirement as SAO director, the resulting hexagonal array of mirrors forming the Multi‐Mirror Telescope had the light‐gathering power of a single 4.5 m telescope, making it the third most powerful telescope in the world at the time. In 1982 the Mount Hopkins facility was renamed the Fred Lawrence Whipple Observatory; in 1998 the MMT was finally replaced by a single 6.5 m telescope.
During the second half his 18 year directorship of SAO, and for three decades more, Fred continued his pursue his scientific interest in comets, broadening this into a more general study of the evolution of the solar system. Following a remark by Al Cameron that “there must be a tremendous mass of small solid material on the outskirts of the solar system,” Fred became very interested in the idea that compositional similarities suggested that Uranus and Neptune were largely formed from cometary material and that the Öpik‐Oort Cloud (as he always termed it) consisted of “cometesimals” thrown to great distances by planetary gravitational perturbations.
In particular, he postulated in a 1964 paper that many of these cometesimals, of which Pluto itself was perhaps one, remained in a belt near the plane of the ecliptic beyond the perturbative reach of Neptune. More specifically, Fred suggested that the largest members of the comet belt had diameters of perhaps 200 km and were therefore of an apparent magnitude of around 22. From the apparent effect on the latitude of Neptune that earlier researchers had attributed to the mass of Pluto, he deduced for the belt a total mass of 10–20 M⊕ in the general range of 40–50 AU from the Sun. In a follow‐up paper that Fred wrote in 1968 in collaboration with Salah Hamid and myself, we established that such a mass would have an unacceptably large effect on the orbits of Halley’s and similar comets and that any comet belt at 40–50 AU could not have a mass of more than perhaps 1.3 M⊕. I must confess that I was at that time quite negative about the existence of any transneptunian comet belt, taking the view that there had to be some completely different reason for the supposed effect on Neptune’s latitude, and that after all, 
. But Fred persisted in his view that the belt existed at some level. A quarter of a century later, of course, that completely different reason became evident with improved analyses of the orbits of the outer planets, and Fred was rewarded with the recognition that there really is a transneptunian belt of cometary material at the range of distance he considered, which evidently has a mass significantly in the direction of our 1968 upper limit.
Earlier in this paper, I mentioned 1930 vintage thoughts by Leuschner, and particularly by Leonard, concerning a possible transneptunian population. This topic was the subject of papers by Kenneth Edgeworth in 1943 and Gerard Kuiper in 1951, and the several hundred transneptunian objects now known are frequently said to belong to the “Kuiper Belt.” However much insight one wishes to ascribe to the first three astronomers, it is rather clear that Kuiper was discussing a transneptunian population that existed exclusively in the early days of the solar system, prior to being thrown to great distances by a massive Pluto, with nothing now remaining. On the other hand, while Fred may have been misled by the nonexistent Neptune‐latitude perturbations, the way he envisaged the transneptunian belt, in terms of its likely origin and as it appears today, is almost precisely correct. Some have wondered why Whipple presented his work with no reference to Kuiper, who was, after all, a good friend of his. The point is that it never occurred to him to do so, for he and Kuiper were describing two very different ideas.
Papers by Fred during the 1980s and 1990s suggested that the flares exhibited by Holmes’ comet in 1892–1893 were due to a graze and later a collision with a satellite comet orbiting the main nucleus, and he later presented this as confirmation of the weak cometary structures noted by Öpik and Zdenek Sekanina. He also developed an “activity index” to categorize specific comets and attempted to correlate this with other characteristics, such as showing that dynamically old comets are statistically less active than new comets and exhibit less dust in their spectra. The Giotto mission to Halley’s comet in 1986 provided a splendid demonstration of the general correctness of his icy conglomerate model. Certainly, one can argue about some of the details. But when some are moved to assert that a comet is more of an “icy dirtball” than a dirty snowball, they miss the whole point of the revolution of cometary science provided by Fred’s 1950 masterpiece. Of course a comet contains “dirt,” but contrary to what his predecessors had argued, it is the ice that makes a comet tick.
As SAO director, Fred had his own particular style with regard to administration. Above all, he made a point of hiring appropriate people to do what was required, and he let them do it with minimal intervention. It was a mark of his directorship to invite scientists from all around the world to carry out their research at SAO, and he took a particularly active role in providing opportunities for women and minorities. Furthermore, during those happy days of increasing funding for science, the unique cooperation between Fred and Don until the latter's retirement in 1966 benefited both SAO and HCO very much, as Don had anticipated. Insofar as he could manage it, Fred restricted his administrative work to mornings, so that the afternoons would be available for scientific research. Every Friday he would receive the week’s supply of requisitions for purchases for his approval. His procedure then involved a rhythmic turning of each page and a rubber stamp of approval at intervals of 5 seconds. But to keep the administrators on their toes, an occasional requisition would be selected for more detailed scrutiny. As for bureaucrats at NASA and elsewhere, he largely ignored them. This applied particularly to the publication of scientific reports, which he had internally reviewed and published without waiting for possibly long‐delayed reviews from the funding agency.
Fred succeeded his colleague Cecilia Payne‐Gaposchkin as Phillips Professor of Astronomy at Harvard in 1968 and became Phillips Professor Emeritus in 1977. He received the Bruce Medal of the Astronomical Society of the Pacific in 1986. Among his many other awards were the J. Lawrence Smith Medal of the National Academy of Sciences in 1949, the Joseph Henry Medal of the Smithsonian Institution in 1973, an Honorary Doctor of Science degree from the University of Arizona in 1979, the Gold Medal of the Royal Astronomical Society in 1983, and the Henry Norris Russell lectureship of the American Astronomical Society in 1987. In 1970 the Meteoritical Society awarded him its memorial medal named for his old mentor, F. C. Leonard. Named to the team of the ill‐fated Comet Nucleus Tour (CONTOUR) in 1999, Fred became the oldest person ever to be an official participant in a NASA project. The following year, the Library of Congress honored him as one of 78 of the world’s “Living Legends.”
In 1946 Fred married Babette Samelson, by whom he had two daughters, Sandra and Laura. He is also survived by a son, Earle Raymond, from his first marriage. There are two granddaughters, Anna and Rebecca Silverstein. A resident of Belmont, just west of Cambridge, Fred cycled to and from work six days a week until the end of his ninth decade, forever eager to best his 11 minute record for the journey. If he had to travel by car, it was recognizable at the Observatory from its license plate, “COMETS.” In earlier times, there was the alternate vehicle, “PLANET.”
For several decades, Fred and Babbie vacationed twice a year at “The Porthole,” their property in the British Virgin Islands, where Fred participated in quite daring snorkeling exploits. At home he was a keen grower of roses, and was also a talented artist. He took a particular interest in what he called “stochastic painting,” which involved the development of a design of polygons from successive pairs of random numbers. The colors used were also established by means of random numbers, and if the pairs were increased to random triplets, one could also incorporate arcs of circles whose radii were computed by means of the golden ratio. Although the use of rules for constructing these paintings may seem anathema to genuine artistry, he insisted that the choice of rules itself involved creativity and self‐expression.
As mentioned near the beginning of this paper, Fred had a Presbyterian upbringing. In his still‐unpublished final paper, entitled “My Conversion to Atheism,” he discussed in some detail his thoughts on religion as they evolved during his progression from sheltered farm life in Iowa through educational advancement in California. Together with his first wife, and encouraged by discussions with Subramanyan Chandrasekhar, this included an examination of extrasensory perception, the fallacies of which he was soon able to expose by means of his almost uncanny ability at estimating numbers and dimensions. This rather fascinating manuscript ends with eight reasons for the success of religion, “the most divisive subject known to mankind.” In discussing his eighth reason—the behavior of one’s unconscious mind—he remarked on how inspection of the clock on waking up at night showed many more occasions when it was exactly on the hour or half‐hour than would be due to chance. He considered it necessary “to watch my unconscious very carefully” when he was doing science: “I have had what seemed like very bright ideas involving a number of uncertain numerical quantities [that were] poorly determined. In making up numbers the best I could for each of the [to be] combined quantities on two different occasions, I came out very close to the [final] number I wanted to get. Later on, I found that the numbers were really not at all right and that the brilliant ideas were absolutely wrong.” Not only is this an interesting admission from one of the giants of 20th century astronomy, but it should surely be a lesson to us all.