A PLANET
NAMED GEORGE

THERE IS ON the Moon a small impact crater called Galilei. It is about 9 miles across, roughly the size of the Elizabeth, New Jersey, greater metropolitan area, and is so small that a fair-sized telescope is required to see it at all. Near the center of that side of the Moon which is perpetually turned toward the Earth is a splendid ancient battered ruin of a crater, 115 miles across, called Ptolemaeus; it is easily seen with an inexpensive set of field glasses and can even be made out, by persons of keen eyesight, with the naked eye.

Ptolemy (second century A.D.) was the principal advocate of the view that our planet is immovable and at the center of the universe; he imagined that the Sun and the planets circled the Earth once daily, imbedded in swift crystalline spheres. Galileo (1564–1642), on the other hand, was a leading supporter of the Copernican view that it is the Sun which is at the center of the solar system and that the Earth is one of many planets revolving around it. Moreover, it was Galileo who, by observing the crescent phase of Venus, provided the first convincing observational evidence in favor of the Copernican view. It was Galileo who first called attention to the existence of craters on our natural satellite. Why, then, is crater Ptolemaeus so much more prominent on the Moon than crater Galileo?

The convention of naming lunar craters was established by Johannes Höwelcke, known by his Latinized name of Hevelius. A brewer and town politician in Danzig, Hevelius devoted a great deal of time to lunar cartography, publishing a famous book, Selenographia, in 1647. Having hand-etched the copper plates used for printing his maps of the telescopic appearance of the Moon, Hevelius was faced with the question of what to name the features depicted. Some proposed naming them after Biblical personages; others advocated philosophers and scientists. Hevelius felt that there was no logical connection between the features on the Moon and the patriarchs and prophets of thousands of years earlier, and he was also concerned that there might be substantial controversy about which philosophers and scientists—particularly if they were still alive—to honor. Taking a more prudent course, he named the prominent lunar mountains and valleys after comparable terrestrial features: as a result we have lunar Apennines, Pyrenees, Caucasus, Juras and Atlas mountains and even an Alpine valley. These names are still in use.

Galileo’s impression was that the dark, flat areas on the moon were seas, real watery oceans, and that the bright and rougher regions densely studded with craters were continents. These maria (Latin for “seas”) were named primarily after states of mind or conditions of nature: Mare Frigoris (the Sea of Cold), Lacus Somniorum (the Lake of Dreams), Mare Crisium (the Sea of Crises), Sinus Iridum (the Bay of Rainbows), Mare Serenitatis (the Sea of Serenity), Oceanus Procellarum (the Ocean of Storms), Mare Nubium (the Sea of Clouds), Mare Fecunditatis (the Sea of Fertility), Sinus Aestuum (the Bay of Billows), Mare Imbrium (the Sea of Rains) and Mare Tranquillitatis (the Sea of Tranquillity)—a poetic and evocative collection of place names, particularly for so inhospitable an environment as the Moon. Unfortunately, the lunar maria are bone-dry, and samples returned from them by the U.S. Apollo and Soviet Luna missions imply that never in their past were they filled with water. There never were seas, bays, lakes or rainbows on the Moon. These names have survived to the present. The first spacecraft to return data from the surface of the Moon, Luna 2, touched down in Mare Imbrium; and the first human beings to make landfall on our natural satellite, the astronauts of Apollo 11, did so, ten years later, in Mare Tranquillitatis. I think Galileo would have been surprised and pleased.

Despite Hevelius’ misgivings, the lunar craters were named after scientists and philosophers by Giovanni Battista Riccioli in a 1651 publication, Almagestum Novum. The title of the book means “The New Almagest,” the old Almagest having been the life’s work of Ptolemy. (“Almagest,” a modest title, means “The Greatest” in Arabic.) Riccioli simply published a map on which he placed his personal preferences for crater names, and the precedent and many of his choices have been followed without question ever since. Riccioli’s book came out nine years after the death of Galileo, and there has certainly been adequate opportunity to rename craters later. Nevertheless, astronomers have retained this embarrassingly ungenerous recognition of Galileo. Twice as large as crater Galileo is one called Hell after the Jesuit father Maximilian Hell.

One of the most striking of the lunar craters is Clavius, 142 miles in diameter and the site of a fictional lunar base in the movie 2001: A Space Odyssey. Clavius is the Latinized name of Christoffel Schlüssel (= “key” in German = Clavius), another member of the Jesuit order, and a supporter of Ptolemy. Galileo engaged in a protracted controversy on the priority of discovery and the nature of sunspots with yet another Jesuit priest, Christopher Scheiner, which developed into a bitter personal antagonism and which is thought by many historians of science to have contributed to the house arrest of Galileo, the proscription of his books, and his confession, extracted under threat of torture by the Inquisition, that his previous Copernican writings were heretical and that Earth did not move. Scheiner is commemorated by a lunar crater 70 miles across. And Hevelius, who objected altogether to the naming of lunar features after people, has a handsome crater named after himself.

Riccioli gave the names Tycho, Kepler and, interestingly, Copernicus to three of the most prominent craters on the Moon. Riccioli himself and his student Grimaldi received large craters at the limb, or edge, of the moon, Riccioli’s being 106 miles across. Another prominent crater is named Alphonsus after Alphonso X of Castile, a thirteenth-century Spanish monarch who had commented, after witnessing the complexity of the Ptolemaic system, that had he been present at the Creation, he could have given God some useful suggestions on ordering the universe. (It is amusing to imagine Alphonso X’s response were he to learn that seven hundred years later a nation across the Western ocean would send an engine called Ranger 9 to the Moon, automatically producing images of the lunar surface as it descended, until finally it crashed in a pre-existing depression named, after His Castilian Majesty, Alphonsus.) A somewhat less prominent crater is named after Fabricius, the Latinized name of David Goldschmidt, who in 1596 discovered that the star Mira varied periodically in brightness, striking another blow against the view championed by Aristotle and supported by the Church that the heavens were unchanging.

Thus the prejudice against Galileo in seventeenth-century Italy did not, in the naming of lunar features, carry over as a completely consistent bias in favor of Church fathers and Church doctrines on matters astronomical. Of the approximately seven thousand designated lunar formations it is difficult to extract any consistent pattern. There are craters named after political figures who had little direct or apparent connection with astronomy, such as Julius Caesar and Kaiser Wilhelm I, and after individuals of heroic obscurity: for example, crater Wurzelbaur (50 miles in diameter) and crater Billy (31 miles in diameter). Most of the designations of small lunar craters are derived from large and nearby craters, as, for example, near the crater Mösting are the smaller craters Mösting A, Mösting B, Mösting C, and so on. A wise prohibition against naming craters after living individuals has been breached only occasionally, as in assigning a few quite small craters to American astronauts of the Apollo lunar missions, and by a curious symmetry in the age of détente, to Soviet cosmonauts who remained behind in Earth orbit.

In this century an attempt has been made to name, consistently and coherently, surface features and other celestial objects by giving this function to special commissions of the International Astronomical Union (IAU), the organization of all professional astronomers on the planet Earth. A previously unnamed bay of one of the lunar “seas,” examined in detail by the American Ranger spacecraft, was officially designated Mare Cognitum (the Known Sea). It is a name not so much of quiet satisfaction as of jubilation. IAU deliberations have not always been easy. For example, when the first—somewhat indistinct—photographs of the far side of the Moon were returned by the historically important Luna 3 mission, the Soviet discoverers wished to name a long, bright marking on their photographs “The Soviet Mountains.” Since there is no major terrestrial mountain range of this name, the suggestion was in conflict with the Hevelius convention. It was accepted, nevertheless, in homage to the remarkable feat of Luna 3. Unfortunately, subsequent data suggest that the Soviet Mountains are not mountains at all.

In a related instance, Soviet delegates proposed naming one of the two maria on the lunar far side (both very small compared with those on the near side) Mare Moscoviense (the Sea of Moscow). But Western astronomers objected that this again departed from tradition because Moscow was neither a condition of nature nor a state of mind. It was pointed out in response that the most recent namings of lunar maria—those on the limbs, which are difficult to make out with ground-based telescopes—have not quite followed this convention either: as Mare Marginis (the Marginal Sea), Mare Orientale (the Eastern Sea) and Mare Smythii (the Smyth Sea). Perfect consistency having already been breached, the issue was decided in favor of the Soviet proposal. At an IAU meeting in Berkeley, California, in 1961, it was officially ruled by Audouin Dollfus of France that Moscow is a state of mind.

The advent of space exploration has now multiplied manyfold the problems of solar system nomenclature. An interesting example of the emerging trend can be found in the naming of features on Mars. Bright and dark surface markings on the Red Planet have been viewed, recorded and mapped from Earth for several centuries. While the nature of the markings was unknown there was an irresistible temptation to name them nevertheless. Following several abortive attempts to name them after astronomers who had studied Mars, G. V. Schiaparelli in Italy and E. M. Antoniadi, a Greek astronomer who worked in France, established around the turn of the twentieth century the convention of naming Martian features after allusions to classical mythological personages and place names. Thus we have Thoth-Nepenthes, Memnonia, Hesperia, Mare Boreum (the Northern Sea) and Mare Acidalium (the Sour Sea), as well as Utopia, Elysium, Atlantis, Lemuria, Eos (Dawn) and Uchronia (which, I suppose, can be translated as Good Times). In 1890, scholarly people were much more comfortable with classical myth than they are today.

THE KALEIDOSCOPIC surface of Mars was first revealed by American spacecraft of the Mariner series, but chiefly by Mariner 9, which orbited Mars for a full year, beginning in November 1971, and radioed back to Earth more than 7,200 close-up photographs of its surface. A profusion of unexpected and exotic detail was uncovered, including towering volcanic mountains, craters of the lunar sort but much more heavily eroded, and enigmatic, sinuous valleys which were probably caused by running water at previous epochs in the history of the planet. These new features cried out for names, and the IAU dutifully appointed a committee under the chairmanship of Gerard de Vaucouleurs of the University of Texas to propose a new Martian nomenclature. Through the efforts of several of us on the Martian nomenclature committee, a serious attempt was made to deprovincialize the new names. It was impossible to prevent major craters being named after astronomers who had studied Mars, but the range of occupations and nationalities could be significantly broadened. Thus there are Martian craters larger than 60 miles across named after the Chinese astronomers Li Fan and Liu Hsin; after biologists such as Alfred Russel Wallace, Wolf Vishniac, S. N. Vinogradsky, L. Spallanzani, F. Redi, Louis Pasteur, H. J. Muller, T. H. Huxley, J. B. S. Haldane and Charles Darwin; after a handful of geologists such as Louis Agassiz, Alfred Wegener, Charles Lyell, James Hutton and E. Suess; and even after a few science-fiction writers such as Edgar Rice Burroughs, H. G. Wells, Stanley Weinbaum and John W. Campbell, Jr. There are also two large craters on Mars named Schiaparelli and Antoniadi.

But there are many more cultures on the planet Earth—even ones with identifiable astronomical traditions—than are represented by any such list of individual names. In an attempt to offset at least in part this implicit cultural bias, a suggestion of mine was accepted to call the sinuous valleys after the names of Mars in other, largely non-European languages. On this page is a table of the most prominent. By a curious coincidence Ma’adim (Hebrew) and Al Qahira (Arabic: the war god after whom Cairo is named) are cheek by jowl. The landing site for the first Viking spacecraft was in Chryse, near the confluence of the Ares, Tiu, Simud and Shalbatana valleys.

TABLE 1
THE FIRST MARTIAN CHANNELS
TO BE NAMED

For the massive Martian volcanoes, one suggestion was to name them after major terrestrial volcanoes, such as Ngorongoro or Krakatoa, which would permit some appearance on Mars of cultures with no written astronomical tradition. But this was objected to on the ground that there would be confusion when comparing terrestrial and Martian volcanoes: Which Ngorongoro are we talking about? The same potential problem exists for terrestrial cities, but we seem able to compare Portland, Oregon, with Portland, Maine, without becoming hopelessly confused. Another suggestion, made by a European savant, was to name each volcano “Mons” (mountain) followed by the name of a principal Roman deity in the appropriate Latin genitive case: thus, Mons Martes, Mons Jovis and Mons Veneris. I objected that at least the last of these had been pre-empted by quite a different field of human activity. The reply was: “Oh, I hadn’t heard.” The outcome was to name the Martian volcanoes after adjacent bright and dark markings in the classical nomenclature. We have Pavonis Mons, Elysium Mons and—satisfyingly, for the largest volcano in the solar system—Olympus Mons. Thus, while the volcano names are very much in the Western tradition, by and large the most recent Mars nomenclature represents a significant break with tradition: an important number of features have been named neither after evocations of classical times nor after European geographical features and nineteenth-century Western visual astronomers.

Some Martian and lunar craters are named after the same individuals. This is the Portland case again, and I think it will cause very little confusion in practice. It does have at least one salutary benefit: on Mars there is today a large crater named Galileo. It is about the same size as the one named Ptolemaeus. And there are no craters on Mars named Scheiner or Riccioli.

Another unexpected consequence of the Mariner 9 mission is that the first close-up photographs of the moons of another planet were obtained. Maps now exist which show about half the surface features on the two Martian moons, Phobos and Deimos (the attendants of the war god, Mars). A subcommittee on Mars satellite nomenclature which I chaired assigned craters on Phobos to astronomers who had studied the moons. A prominent crater at Phobos’ south pole is named after Asaph Hall, the discoverer of both moons. Astronomical apocrypha has it that Hall was on the verge of giving up his search for the Martian moons when he was directed by his wife to return to the telescope. He promptly discovered them and named them “fear” (Phobos) and “terror” (Deimos). Accordingly, the largest crater on Phobos was given Mrs. Hall’s maiden name, Angelina Stickney. Had the impacting object that excavated crater Stickney been any larger, it probably would have shattered Phobos.

Deimos is reserved for writers and others who were in some way involved with speculations about the moons of Mars. The two most prominent features are named after Jonathan Swift and Voltaire, who, in their speculative romances, Gulliver’s Travels and Micromégas, respectively, prefigured before the actual discovery the existence of two moons around Mars. I wanted to name a third Deimonic crater after René Magritte, the Belgian surrealist whose paintings “Le Château des Pyrénées” and “Le Sens de Réalité” pictured large rocks, suspended in the sky, of an aspect astonishingly like the two Martian moons—except for the presence in the first painting of a castle, which, so far as we know, does not surmount Phobos. The suggestion was, however, voted down as frivolous.

THIS IS THE moment in history when the features on the planets will be named forever. A crater name represents a substantial memorial: the estimated lifetime of large lunar, Martian and Mercurian craters is measured in billions of years. Because of the enormous recent increase in the number of surface features that need to be named—and also because the names of almost all dead astronomers have already been given to one or another celestial object—a new approach is needed. At the IAU meeting in Sydney, Australia, in 1973, several committees were appointed to look into questions of planetary nomenclature. One clear problem is that if craters on other planets are now named after a category other than people, we will be left with only the names of astronomers and a few others on the Moon and planets. It would be charming to name craters on, say, Mercury, after birds or butterflies, or cities or ancient vehicles of exploration and discovery. But if we accept this course, we will leave the impression on globes and maps and textbooks that we esteem only astronomers and physicists; that we care nothing for poets, composers, painters, historians, archaeologists, playwrights, mathematicians, anthropologists, sculptors, physicians, psychologists, novelists, molecular biologists, engineers and linguists. The proposal that such individuals be commemorated with unassigned lunar craters would result, say, in Dostoevsky or Mozart or Hiroshige assigned craters a tenth of a mile across, while Pitiscus is 52 miles in diameter. I do not think this would speak well for the breadth of vision and intellectual ecumenicism of the name-givers.

After a protracted debate this point of view has prevailed—in significant part due to its vigorous support by Soviet astronomers. Accordingly, the Mercury nomenclature committee, under the chairmanship of David Morrison of the University of Hawaii, has decided to name Mercurian impact craters after composers, poets and authors. Thus, major craters are named Johann Sebastian Bach, Homer and Murasaki. It is difficult for a committee of largely Western astronomers to select a group of names representative of all of world culture, and Morrison’s committee requested help from appropriate musicians and experts in comparative literature. The most vexing problem is to find, for example, the names of those who composed Han dynasty music, cast Benin bronzes, carved Kwakiutl totem poles and compiled Melanesian folk epics. But even if such information comes in slowly, there will be time: the Mariner 10 photography of Mercury, which discovered the features to be named, covered only half the surface of the planet, and it will be many years before the craters in the other hemisphere will be photographed and named.

In addition, there are a few objects on Mercury that have been recommended for other sorts of names for special purposes. The proposed 20° meridian of longitude passes through a small crater which the Mariner 10 television experimenters have suggested calling Hun Kal, the Aztec word for “twenty,” the base of Aztec arithmetic. And they have suggested calling an enormous depression, in some senses comparable to a lunar mare, the Caloris basin: Mercury is very hot. Finally, all of these names apply only to the topographic features of Mercury; the bright and dark markings, glimpsed dimly by past generations of ground-based astronomers, have not yet been mapped reliably. When they are, there will probably be new suggestions for naming them. Antoniadi proposed names for such features on Mercury, some of which—such as Solitudo Hermae Trismegisti (the solitude of Hermes, the thricegreat)—have a fine ring and perhaps will ultimately be retained.

NO PHOTOGRAPHIC maps of the surface of Venus exist, because the planet is perpetually enshrouded by opaque clouds. Nevertheless, surface features are being mapped by ground-based radar. Already it is apparent that there are craters and mountains, and other topographical features of stranger aspect. The success of the Venera 9 and 10 spacecraft in obtaining photographs of the planet’s surface suggests that someday photographs may be returned from aircraft or balloons in the lower Venus atmosphere.

The first prominent features discovered on Venus, regions highly reflective to radar, were given unassuming names such as Alpha, Beta and Gamma. The present Venus nomenclature committee, under the chairmanship of Gordon Pettengill of the Massachusetts Institute of Technology, proposes two categories of names for Venus surface features. One category would be pioneers in radio technology whose work led to the development of the radar techniques that permit mapping the surface of Venus: for example, Faraday, Maxwell, Heinrich Hertz, Benjamin Franklin and Marconi. The other category, suggested by the name of the planet itself, would be women. At first glance, the idea of a planet devoted to women may appear sexist. But I think the opposite is true. For historical reasons, women have been discouraged from pursuing the sorts of occupations now being memorialized on other planets. The number of women after whom craters have so far been named is very small: Sklodowska (Madame Curie’s maiden name); Stickney; the astronomer Maria Mitchell; the pioneer nuclear physicist Lisa Meitner; Lady Murasaki; and only a few others. While by the occupational rules for other planets women’s names will continue to appear occasionally on other planetary surfaces, the Venus proposal is the only one that permits adequate recognition to be made of the historical contribution of women. (I am glad, however, that this idea will not be applied consistently; I would not myself want to see Mercury covered with businessmen and Mars with generals.)

In a fashion, women have traditionally been commemorated in the asteroid belt (see Chapter 15), that collection of rocky and metallic boulders which circle the Sun between the orbits of Mars and Jupiter. With the exception of a category of asteroids named after heroes of the Trojan War, it used to be that all asteroids were named after women. First it was largely women of classical mythology, such as Ceres, Urania, Circe and Pandora. As available goddesses dwindled, the scope broadened to include Sappho, Dike, Virginia and Sylvia. Then, as the floodgates of discovery opened and the names of astronomers’ wives, mothers, sisters, mistresses and great-aunts were exhausted, they took to naming asteroids after real or hoped-for patrons and others, with a female ending appended, as, for example, Rockefelleria. By now more than two thousand asteroids have been discovered, and the situation has become moderately desperate. But non-Western traditions have hardly been tapped, and there are a multitude of Basque, Amharic, Ainu, Dobu and !Kung feminine names for future asteroids. In anticipation of an Egyptian-Israeli détente, Eleanor Helin of the California Institute of Technology proposed calling an asteroid she discovered Ra-Shalom. An additional problem—or opportunity, depending on how one views it—is that we may soon obtain close-up photographs of asteroids, with surface details that will cry out to be named.

Beyond the asteroid belt, on the planets and large moons of the outer solar system, no nondescriptive names have so far been bestowed. Jupiter, for example, has a Great Red Spot and a North Equatorial Belt, but no feature called, say, Smedley. The reason is that when we see Jupiter we are looking at its clouds, and it would not be a very fitting or at least not a very long-lived memorial to Smedley to name a cloud after him. Instead, the present major question on nomenclature in the outer solar system is what to name the moons of Jupiter. The moons of Saturn, Uranus and Neptune have satisfying or at least obscure classical names (see Table 2). But the situation for the fourteen moons of Jupiter is different.

TABLE 2
NAMES OF THE SATELLITES
OF THE OUTER PLANETS

The four large moons of Jupiter were discovered by Galileo, whose theological contemporaries were convinced by a vague amalgam of Aristotelian and Biblical ideas that the other planets could have no moons. The contrary discovery by Galileo was disconcerting to fundamentalist churchmen of the time. Possibly in an effort to circumvent criticism, Galileo called the moons the Medicean satellites—after his funding agency. But posterity has been wiser: they are known instead as the Galilean satellites. In a similar vein, when William Herschel of England discovered the seventh planet he proposed calling it George. If wiser heads had not prevailed, we might today have a major planet named after George III. Instead we call it Uranus.

The Galilean satellites were assigned their Greek mythological names by Simon Marius (commemorated on the Moon by a crater 27 miles across), a contemporary of Galileo and a disputant with him for the priority of their discovery. Marius and Johannes Kepler felt that it would be extremely unwise to name celestial objects after real people and particularly after political personages. Marius wrote: “I want the thing done without superstition and with the sanction of theologians. Jupiter especially is charged by the poets with illicit loves. Especially well-known among these are three virgins, whose love Jupiter secretly coveted and obtained, namely: Io … Callisto … and Europa … Yet even more ardently did he love the beautiful boy Ganymede … and so I believe that I have not done badly in naming the first Io, the second Europa, the third, on account of the splendor of its light, Ganymede, and lastly the fourth Callisto.”

However, in 1892 E. E. Barnard discovered a fifth moon of Jupiter with an orbit interior to Io’s. Barnard resolutely insisted that this satellite should be called Jupiter 5 and by no other name. Since then, Barnard’s position has been maintained, and of the fourteen Jovian moons now known, only the Galilean satellites had, until recently, names officially sanctioned by the IAU. However unreasonable it may be, people show a strong preference for names over numbers. (This is clearly illustrated in the resistance of college students to being considered “only a number” by the college bursar; by the outrage of many citizens at being known to the government only by their social security number; and by the systematic attempts in jails and prison camps to demoralize and degrade the inmates by assigning them a numeral as their only identity.) Soon after Barnard’s discovery, Camille Flammarion suggested the name Amalthea for Jupiter 5 (Amalthea was in Greek legend the goat that suckled the infant Zeus). While being suckled by a goat is not precisely an act of illicit love, it must have seemed, to the Gallic astronomer, adequately close.

The IAU committee on Jovian nomenclature, chaired by Tobias Owen of the State University of New York at Stony Brook, has proposed a set of names for Jupiter 6 through 13. Two principles guided their selection: the name chosen should be that of “an illicit love” of Jupiter, but one so obscure as to have been missed by those indefatigable cullers of the classics who name asteroids, and must end with an a or an e depending on whether the moon goes around Jupiter clockwise or counterclockwise. But in the opinion of at least some classical scholars, these names are obscure to the point of bewilderment, and the result leaves many of the most prominent Jovian paramours unrepresented in the Jupiter system. The result is particularly poignant in that Hera (Juno), the wife so often scorned by Zeus (Jupiter), is not represented at all. Evidently, she was inadequately illicit. An alternative list of names, which includes most of the prominent paramours as well as Hera, is also shown in the table below. Were these names employed, it is true they would duplicate asteroid names. This is in any case already a fact for the four Galilean satellites, where the amount of confusion thus engendered has been negligible. On the other hand, there are those who support Barnard’s position that numbers are sufficient; prominent among these is Charles Kowal^* of the California Institute of Technology, the discoverer of Jupiter 13 and Jupiter 14. There seems to be merit in all three positions and it will be interesting to see how the debate turns out. At least we do not yet have to judge the merits of contending suggestions for naming features on the Jovian satellites.

TABLE 3
PROPOSED NAMES FOR JOVIAN SATELLITES

But that time is not long off. There are thirty-one known moons of Jupiter, Saturn, Uranus and Neptune. None has been photographed close up. The decision has recently been made to name features on the moons in the outer solar system after mythological figures from all cultures. However, very soon the Voyager mission will obtain high-resolution images of about ten of them, in addition to the rings of Saturn. The total surface area of the small objects in the outer solar system greatly exceeds the areas of Mercury, Venus, Earth, Moon, Mars, Phobos and Deimos together. There will be ample opportunity for all human occupations and cultures to be represented eventually, and I daresay provisions for nonhuman species can also be made. There are probably more professional astronomers alive today than in the total prior recorded history of mankind. I suppose that many of us will also be commemorated in the outer solar system—a crater on Callisto, a volcano on Titan, a ridge on Miranda, a glacier on Halley’s comet. (Comets, incidentally, are given the names of their discoverers.) I sometimes wonder what the arrangement will be—whether those who are bitter rivals will be separated by being placed on different worlds, and whether those whose discoveries were collaborative will nestle together, crater rampart to crater rampart. There have been objections that political philosophers are too controversial. I myself would be delighted to see two enormous, adjacent craters called Adam Smith and Karl Marx. There are even enough objects in the solar system for dead political and military leaders to be accommodated. There are those who have advocated supporting astronomy by selling crater names to the highest bidders, but I think this goes rather too far.

THERE IS A curious problem about names in the outer solar system. Many of the objects there have extremely low density, as if they were made of ice, great fluffy snowballs tens or hundreds of miles across. While objects impacting these bodies will certainly produce craters, craters in ice will not last very long. At least for some objects in the outer solar system, named features may be transient. Perhaps that is a good thing: it would give us a chance to revise our opinions of politicians and others, and will give eventual recourse if flushes of national or ideological fervor are reflected in solar system nomenclature. The history of astronomy shows that some suggestions for celestial nomenclature are better ignored. For example, in 1688 Erhard Weigel at Jena proposed a revision of the ordinary zodiacal constellations—the lion, virgin, fish and water carrier that people have in mind when they ask you what “sign” you are. Weigel proposed instead a “heraldic sky” in which the royal families of Europe would be represented by their tutelary animals: a lion and a unicorn for England, for example. I hate to imagine descriptive stellar astronomy today had that idea been adopted in the seventeenth century. The sky would be carved into two hundred tiny patches, one for each nation-state existing at the time.

The naming of the solar system is fundamentally not a task for the exact sciences. It has historically encountered prejudice and jingoism and lack of foresight at every turn. However, while it may be a little early for self-congratulation, I think astronomers have recently taken some major steps to deprovincialize the nomenclature and make it representative of all of humanity. There are those who think it is a pointless, or at least thankless, task. But some of us are convinced it is important. Our remote descendants will be using our nomenclature for their homes: on the broiling surface of Mercury; by the banks of the Martian valleys; on the slopes of Titanian volcanoes; or on the frozen landscape of distant Pluto, where the Sun appears as a point of bright light in a sky of unremitting blackness. Their view of us, of what we cherish and hold dear, may be determined largely by how we name the moons and planets today.