Planet Mars Chronology

This is a comprehensive year-by-year survey of the planet Mars and its influence in the history of science and culture.

See also Planet Mars in Popular Culture

Mars chronology: Renaissance to the Space Age
Compiled by Paul Karol and David Catling

The 1500s: The Copernican Revolution

Danish astronomer Tycho Brahe (1546-1601) collects very accurate positions for Mars using keen eyesight and large measuring instruments. Positions of stars and planets are monitored to an accuracy of about four minutes of arc.

On the Revolutions of the Heavenly Orbs by Nicolaus Copernicus (1473-1543) is published. This contains the radical notion that the planets, including the Earth, orbit the Sun, which challenges conventional beliefs concerning the central position of the Earth. The belief that the Earth was at the center of the universe was essentially a reconciliation of classical Aristotelian philosophy and Judaic-Christian theology that owed much to St. Thomas Aquinas.

The 1600s: Pioneers of Planetary Motion and Gravitation

Johannes Kepler (1571-1630) goes to Prague to become assistant to Tycho Brahe, who dies a year later.

Giordano Bruno (1548-1600), an Italian scientist who taught at Oxford and other well-known European universities, is tried by the Inquisition, condemned, and burned at the stake. He had dared to suggest that space is boundless and that the sun and its planets were but one of any number of similar systems. He even said that there might be other worlds inhabited with rational beings possibly superior to ourselves.

Kepler publishes his Astronomia Nova (New Astronomy), containing his first two laws of planetary motion. Kepler's first law is based on a calculation of an elliptical orbit for Mars using Brahe's data. This challenged, and ultimately replaced, the classical belief in perfect circular orbits.

Galileo Galilei (1564-1642) observes Mars with his primitive telescope. Later in 1610, he writes to his friend Father Castelli about observations of phases of Mars indicating a spherical body illuminated by the Sun.

Kepler's Harmonice mundi (The Harmonies of the World) is published. This contains his third law of planetary motion.

Francisco Fontana views and draws Mars. His drawing resembles a dark spot, which he called a "black pill", inside a sphere. The dark spot was due to a defect in his telescope.

Niccolo Zucchi (1586-1670), a professor at the Jesuit College in Rome, observes spots on Mars with his reflecting telescope. In 1616, Zucchi had made one of the earliest reflecting telescopes, predating those of James Gregory and Sir Isaac Newton.

October 13: The first sketch of Mars is drawn by the Dutch astronomer Christiaan Huygens (1629-1695). Huygens uses his own design of telescope, which is of much higher quality than that of his predecessors and allows a magnification of 50 times.

November 28: Christiaan Huygens records the first true feature on Mars, a large dark spot, almost certainly Syrtis Major, which became known as the "Hourglass Sea". Observing the spot in successive rotations, he deduces a 24 hour period. Huygens had earlier made some drawings of Mars in 1656, but they were not noteworthy because Mars had passed opposition in July 1655, giving a poor view.

Mars is in opposition. Giovanni Domenico Cassini (1625-1712) draws Mars and determines a day length of 24 hours 40 minutes. Cassini made about 20 crude drawings of Mars at the observatory in Bologna, and from them noticed that markings came back to the same positions about forty minutes later than on the previous day. Cassini also saw the polar caps.

Jean Richer (1630-1696) travels to Cayenne, French Guyana, and measures the parallax of Mars at its perigee, at the behest of the French government. Later Cassini compares Richer's measurements with his own measurements of Mars' position relative to the stars, and the distances of Mars and the Sun from the Earth are determined. This produces the first reasonably accurate dimensions of the solar system. Cassini deduced an Earth-Sun distance, known as an Astronomical Unit, of 140 million km (87 million miles) compared to the modern value of 149.6 million km (93 million miles).

In September, Mars is in opposition, and Huygens observes a white spot at the south pole of Mars, i.e. the southern polar cap.

La Pluralité des Mondes (The Inhabitation of Worlds) is published by Bernard de Fontenelle, a respected French astronomer. The book, written as a dialogue, discusses evidence for life on planets in the solar system. Fontenelle, however, believed Mars to be uninhabitable, so the planet receives little attention: "It is also five times as small as the Earth [NB: really it has half the diameter] and receives much less sun. In short, Mars is not worth the trouble of stopping at. A much prettier choice would be Jupiter with her four moons!".

Isaac Newton publishes his Principia, which introduces his principle of universal gravitation and provides a physical basis for the orbits of the planets.

Huygens' Cosmotheoros is posthumously published (Huygens died in 1695 and had written the book some years earlier). This addresses the question of life on Mars - one of the earliest expositions on extraterrestrial life - and Huygens deduces that though Mars will be colder than Earth, because it is further from the Sun, life there will have adapted. He also discusses what is required for a planet to be capable of supporting life and speculates about intelligent extraterrestrials.

The 1700s: Mars, a planet similar to Earth

Giacomo Filippo Maraldi (Cassini's nephew) of the Paris Observatory, records "white spots" at the poles but stops short of calling them ice caps. Because the southern pole is tilted towards the Earth, it is easier to observe and he discovers that the south cap is not centered on the rotational pole.

Giacomo Maraldi suggests that the white spots at the poles of Mars could be interpreted as ice caps. Maraldi also notes that the southern cap changes in size and disappears in August and September, only to return later.

1719: Mars is in opposition and closer to Earth than it would be for another 284 years (i.e. until 2003!). The brightness of Mars in the sky is interpreted as a bad omen and causes concern.

Gulliver's Travels written by Jonathan Swift (1667-1745) seems to speculate that there are two moons of Mars, although this must have been a lucky guess.

Abraham Kastner, a poet and anti-pluralist, publishes a poem about his pluralist friend, Christob Mylius, who had died in 1752. In the poem, Mylius' soul travels across the solar system. On Mars, Mylius meets the "eternal souls" of Martians.

Observations of Mars are made by Frederick Wilhelm "William" Herschel (1738-1822), the British Astronomer Royal. Sir William Herschel did various studies of Mars between 1777 and 1783 using telescopes that he made himself. In 1781, he discovered the planet Uranus, and this led George III of England to grant him a pension for life to study astronomy.

A 30 degree axial tilt of Mars is identified by Herschel as published in his paper in The Philosophical Transactions entitled "On the remarkable appearances at the polar regions on the planet Mars, the inclination of its axis, the position of its poles, and its spheroidal figure; with a few hints relating to its real diameter and atmosphere." (Note: the modern scientific value for the axial tilt of Mars relative to its orbital plane is 25.19 degrees.) Hershel notes the seasonal changes of the polar caps and suggests they are snow and ice. He wrongly considers the dark areas to be oceans. On October 26 and 27 of 1783, Herschel observed two faint stars that passed near Mars, within a few seconds of arc. Because the light from these stars was not affected, Herschel correctly concludes that Mars has a tenuous atmosphere because he could see no effect on the near occultation of these dim stars. Hershel compares the remarkable similarity of Mars to the Earth: "The analogy between Mars and the earth is, perhaps, by far the greatest in the whole solar system. The diurnal motion is nearly the same; the obliquity of their respective ecliptics, on which the seasons depend, not very different; of all the superior planets the distance of Mars from the sun is by far the nearest alike to that of the earth: nor will the length of the martial year appear very different from that which we enjoy"

The 1800s: Martian cartography, the canal craze, and psychic connections to Mars

Johann Hieronymus Schroeter, an enthusiastic amateur astronomer, does some Mars drawings. He is in regular correspondence with Herschel and owns telescopes made with Herschel's components.

Honeré Flaugergues, a French amateur working at his private observatory in Viviers in southeastern France, notes the presence of "yellow clouds" on Mars. These were much later identified as dust clouds. Flaugergues later discovered the Great Comet of 1811.

Flaugergues notices rapid melting of ice caps on Mars. He notes that markings were variable, and that in Martian spring, the polar cap shrinks rapidly. Flaugergues assumes that the cap comprises thick layers of ice and snow, and that its rapid melting signifies that Mars is hotter than the Earth.

Drawings are made by Wilhelm Beer (1797-1850) and Johann von Maedler (1794-1874) at Beer's private observatory near Berlin. They generate a global map of Mars and make 3 determinations of the rotation period using baselines of 759, 1604 and 2234 days, the average value of which gave 24 hours, 37 minutes, 22.6 seconds (compared with modern science's textbook value of 24 hrs, 37 min, 22.7 sec). Earlier in 1836, Beer and Maedler had also generated the most complete map of the Moon, Mappa Selenographica, in their time, which remained unsurpassed until 1878, when a more detailed map appeared.

William Whewell, a fellow of Trinity College, Cambridge Univeristy, and philosopher of science, theorizes about Mars. He supposes that it has green seas, red land, and possibly life forms. Earlier in 1830, Whewell introduced the term "scientist" to the English language.

Pietro Angelo Secchi (1818-1878), a Jesuit monk and director of the Roman College Observatory, draws a map of Mars calling Syrtis Major the "Atlantic Canal". Secchi, despite his closeness to the Vatican, believed in the plurality of worlds. Earlier, in 1856 he wrote (in Descrizione del nuovo osservatorio del collegio romano): "it is with a sweet sentiment that man thinks of these worlds without number, where each star is a sun which, as minister of the divine bounty, distributes life and goodness to the other innumerable beings, blessed by the hand of the Omnipotent." He conceded that these worlds may not be accessible to his telescopes, but by analogy with the earth and the solar system he was persuaded that the universe is a wonderful organism filled with life.

Work begins on the Suez Canal, the engineering marvel of its time. Canals move commerce in many parts of the world, but this is the big one, considered equal to the pyramids. The importance of canals at this time in the nineteenth century no doubt influenced the later mistaken interest in "canals" on Mars.

Emmanuel Liais proposes vegetation on Mars. He suggests that dark regions are not seas, as is commonly thought by other observers such as Secchi, but rather, are vegetation tracts.

Sir Joseph Norman Lockyer (1836-1920), of the Royal College of Science in London (later known as Imperial College), makes drawings of Mars. He agrees with Secchi that the "green" areas of Mars are oceanic. Lockyer is best known as the discoverer of the element helium, which he identified from an emission line in the solar spectrum in 1870.

Frederik Kaiser in Holland gives a rotational period of 24h 37m 22.62s. (modern textbook value: 24h 37m, 22.663+/-0.002 s)

The first color sketches of Mars are made by Father Pietro Angelo Secchi (1818-1878).

The English astronomer, William Dawes (1799-1868), makes some exceptionally accurate drawings of Mars. Earlier in 1857, Dawes had observed Jupiter's Great Red Spot, several years before its existence was generally recognized.

Richard Anthony Proctor, a British amateur astronomer and writer of popular astronomy, publishes a map of Mars with continents and oceans based on Dawes' drawings. His nomenclature, which names features after various astronomers, fails to find favor but his choice of zero meridian survives. Later a naming system prescribed by Schiaparelli is adopted.

The first attempts are made to detect oxygen and water vapor spectroscopically, producing inconclusive results, by Pierre Jules Janssen (1824-1907) and Sir William Huggins (1824-1910).

Father Secchi refers to "canali", Italian for channels.

The Suez Canal is completed. In a letter to the first issue of the scientific journal Nature (November, 4), T. Login writes "The all-engrossing topic of the day is the Suez Canal, about which some diversities of opinion still exist." Everyone is talking about the canal!

The red color of Mars is (wrongly) attributed to vegetation. Pop. Sci. Mo. v. IV p.190. In this article, Camille Flammarion suggests "May we attribute to the color of the herbage and plants which no doubt clothe the plains of Mars, the characteristic hue of that planet..."

Giovanni Virginio Schiaparelli (1835-1910) director of the Brera Observatory in Milan, develops a new nomenclature for the mapping of Mars. He names the Martian "seas" and continents by taking the names from historic and mythological sources, as well as terrestrial lands and various terms for hell.

1877: Mars comes into perihelic opposition in September, withing 56 million km of the Earth. Schiaparelli sees "canali" on Mars, meaning channels. This later proves to be very significant in Mars folklore. Schiaparelli casually uses Secchi's terms canale and canali to describe streaks that he has recorded on the Martian surface. This gets mistranslated into English as "canals", which has connotations of Martian intelligent life.

Aug 10, 1877 Asaph Hall (1829-1907), a largely self-taught American astronomer, comes from an impoverished family. By 1863, he is appointed professor of mathematics at the U.S. Naval Observatory in Washington, DC. On this day he gives up a search for Martian moons.

Aug 11, 1877 Asaph Hall, who had resumed his search at the insistence of his wife, Angelina, detects a faint object near Mars.

Aug 12, 1877: Is Mars inhabited?, an editorial in The New York Times. As the best opposition since 1798 approaches, questions in the popular mind come to the fore and the possibility of life on Mars is discussed in the press.

Aug 18, 1877. Asaph Hall announces the discovery of Mars' two moons. At the suggestion of Henry Madan (1838-1901), the Science Master of Eton, England, Hall names the moons Phobos (fear) and Deimos (flight). These two names are variously attributed in Roman mythology to the sons of the god Mars by Aphrodite and also to the horses that pulled the Mars' chariot. Later from 1896 to 1901, Asaph Hall was professor of astronomy at Harvard. Later still, in 1930, Henry Madan's 11-year old niece, Venetia Burney, suggests the name Pluto for that newly-discovered planet to its discoverers.

Phobos is a heavily cratered, small, irregular body that measures 26.6 km (16.5 miles) across at its widest point. It orbits Mars every 7.65 hours at an average distance of 9,378 km (5,814 miles) in a nearly circular orbit that lies only 1 degree from Mars's equatorial plane. It has very low density, about 2 grams per cubic centimetre. It is being pulled towards Mars so that in about 1 billion years time it will crash.
Deimos is a small, irregular, cratered body measuring approximately 15 by 12 by 11 km (9 by 7 by 7 miles). It orbits the planet every 30.3 hours at an average distance of 23,459 km (14,545 miles) in a nearly circular orbit that lies within 2 degrees of Mars's equatorial plane. The satellite's longest axis is always directed toward Mars, so only one side faces Mars, rather like the Moon around the Earth.

Aug 30, 1877. A third moon is allegedly discovered. No, really! The New York Times report that Dr Henry Draper of New York and Edward Singleton Holden of Washington claim to have jointly discovered the third moon at Dr Draper's private observatory at Hastings-on-the-Hudson. This discovery proved to be false; in fact, the proposed moon did not even obey Kepler's laws.

American astronomer, Charles Augustus Young (1834-1908), makes accurate measurements of the diameter of Mars. He was professor of astronomy at Princeton University from 1877 to 1905, and author of General Astrononmy (1888).

1879: Simon Newcomb (1835-1909), a Canadian-born American astronomer, founds the Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, a series of memoirs giving "a systematic determination of the constants of astronomy from the best existing data". These remarkably accurate tables were used throughout most of the world for calculating daily positions of celestial objects until 1959, and even afterward for the Sun, Mercury, Venus, and Mars.

1879: Schiaparelli reports double canali, an example of a notorious phenomenon that came to be known as "gemination".

Percy Gregg, a British author, publishes Across the Zodiac, a two-volume novel about a trip to Mars. His Mars had pale green skies and orange foliage.

Schiaparelli revises his Mars map, adding more canali which now include 20 examples of "gemination"

Canals on the planet Mars are discussed in the press. New York Times Apr. 24, NYT Apr. 27., Richard Proctor waffles on the Canals of Mars. NYT May 2.

"Vegetation on Mars may be red..."--Langley. Century, Mar. p.705. This article reiterates what Flammarion said about the color of Martian vegetation in 1873. "Why, we may ask, is not the Martian vegetation green? Why should it be -- is the reply?", Flammarion later writes in his book La Planète Mars.

Edward Emerson Barnard (1857-1923), an astronomer at Lick Observatory, Mt. Hamilton, California, observes Mars in a position not directly opposite the Sun, when detail is revealed through shadowing. Renowned for his remarkable eyesight, he observes Martian craters but does not make the observation public.

A rich French widow, Clara Gouguet Guzman, offers a prize of 100,000 francs for communication with extraterrestrials. The prize is to be awarded to "the person of whatever nation who will find the means within the next ten years of communicating with a star (planet or otherwise) and of receiving a response". The prize was administered by the French Academy of Sciences and was named the Pierre Guzman Prize after Mme. Guzman's son. Mme. Guzman excludes Mars, considering it "too easy" to contact!

Nicolas Camille Flammarion publishes Volume 1 (608 pages) of his encyclopaedia of La Planète Mars et ses Conditions d'Habitabilité (Gauthier-Villars et Fils, Paris).

1892 Telegraphing to Mars with solar signals in The Spectator, Ap 13. This is one of the first articles that deals with the language problems involved in communicating with the Martials (sic). The article points out that mathematical information may perhaps be exchanged, but questions how we will communicate abstract concepts: "How are we to ask if Martials [sic] have engineers and ships, and electric lights and glaciers and five senses, and heads and feet..."? [Ed.- note that sometimes in the 19th century, Martians were referred to as `Martials']

1892 Camille Flammarion suggests communication with the Martians. Flammarion was familiar with experiments Edison had done with long telephone lines. Edison picked up sounds he felt were caused by "terrestrial magnetism" years before Marconi. Flammarion suggests the natural magnetism of the Earth might be harnessed to propagate sounds across space. (NB 1894: "Wireless" telegraphy is demonstrated by Sir Oliver Lodge)

Percival Lowell (1855-1916) builds the Lowell Observatory at Flagstaff, Arizona, and makes his first observations of Mars.

1894 Edward Emerson Barnard (1857-1923) reports on his observations of Mars including his complete failure to detect canals.

Mars, by Percival Lowell is published.

The New York Herald claims that surface features on Mars are observed to form the Hebrew word for God.

Helene Smith, a Swiss medium of real name Catherine Elise Muller from Geneva, has visions of Mars while under hypnosis induced by the eminent psychologist Theodore Flournoy. Smith imagines herself standing on Mars and meets Martians. She can even speak Martian, which is similar to French. Flournoy later describes his subject in From India to the Planet Mars (Harper and Bros, 1900).

Mrs Smead, an American medium, communicates with her dead daughter and brother-in-law on Mars. Smead describes canals and Martians very similar to humans. Smead was examined by psychologist Prof. J. Hyslop, who concluded she had a multiple personality disorder. (J. Hyslop, Psychical Research and the Resurrection, Small/Maynard, 1908; and also 'Communicating with Mars', editorial in the Independent (periodical), p.1042-43, 1909.)

Herbert G. Wells' (1866-1946) The War of the Worlds is serialized in Pearson's Magazine. It is also printed in the US in The Cosmopolitan

The War of the Worlds is published in hardback.

1898 Garrett Serviss publishes Edison's Conquest of Mars. In this "sequel" to The War of the Worlds, Americans retroengeneer Martian flying machines, go to Mars, and fight Martians! Among the scientist-warriors who accompanied the Americans were Lord Kelvin, Lord Rayleigh, Professor Roentgen, and (guess what?) popular science writer, Garrett Serviss.

Carl Jung's 15-year old patient, "Miss S.W.", goes to Mars in trances, and sees canals and Martians in flying machines. Jung deduces that S.W. is suffering from a dissociated personality. (Jung, C., Zur Psychologie und Pathologie sogennter Occulter Phanomene, Muntze, 1902)

The 1900s: Gradual end of old superstitions and dawning of the Space Age

American astronomer William Henry Pickering, the director of the Lick Observatory, reports "shaft of light" seen to project from Mars (New York Times, Jan 16)

Nikola Tesla (1856-1943), a brilliant Serbian-American inventor and scientist, is building a wireless system to communicate with Martians. (N. Tesla, "Talking with the planets", Collier's Weekly, Vol 24, 4-5, 1901).

Guglielmo Marconi sends the first official wireless message across the Atlantic from Glace Bay, Nova Scotia, Canada to England.

The Wright brothers first airplane flight.

Interplanetary Telephone: Nikola Tesla may use an oscillator to "wake up" Mars according to the New York Times, Jan 15

1905: Photograph Mars Canals-Lowell. On May 28, The New York Times prints Lowell's report that the canals of Mars have been photographed for the first time.

Mars and Its Canals by Lowell is published.

1906 Earl C. Slipher arrives at the Lowell Observatory . He continues photographic studies begun in 1901 into the 1960s. In total, 126,000 images are taken.

Prof. David Peck Todd of Amherst College, and Slipher go to open desert in Alianza, Chile, to photograph Mars to get the clearest seeing possible. Todd and crew took a specially built camera.

1907: Nikola Tesla in letter to The New York Times (Jan 23); "I can easily bridge the gulf which separates us from Mars". A testy Tesla rages at the press for calling his transmitter nothing more than a "useful piece of electrical apparatus"

1907: Slipher makes photos of the Martian canals. At least this is what the July 3 New York Times reports after receiving a telegram from Lowell which reads "Todd of the Lowell expedition to the Andes, cables Mars canals photographed there by Slipher."

December: Century Magazine prints the photos of Mars: tiny, disappointing photos that were Lowell's "proof". Even at a 2 diameter enlargement, they are less than half a centimeter wide. Further enlargements only show successive loss of detail due to enlargement of emulsion grains.

1907 "...the proof by astronomical observations...that conscious, intelligent human life exists upon the planet Mars," is reported as one of the most momentous events of 1907 by the Wall Street Journal.

Percival Lowell's Mars as the Abode of Life is first published in Century Magazine as a series of articles defending the hypothesis of Martian life. It is later published as a book by Macmillan, New York.

George Ellery Hale (1868-1938), using the Mt. Wilson 60" reflector, sees "...not a trace" of canals.

1909: William Pickering proposes mirroring signals to Mars: a signaling system of sufficient size can be constructed for $10M, he argues.

1909: W. W. Campbell of Lick Observatory, tries to measure water vapor in the Martian atmosphere using spectroscopy from an expedition to Mount Witney. Results are negative and he (correctly) concludes that the Martian atmosphere is extremely arid compared to the Earth.

1909 Camille Flammarion publishes the second volume of his encyclopaedia of Mars La Planète Mars et ses Conditions d'Habitabilité (Gauthier-Villars et Fils, Paris). Vol 2 (595 pages) contains 426 drawings and 16 maps from the period 1860 to 1901.

An unfortunate dog, minding its own business in Nakhla, Egypt, is struck by part of a meteorite and killed. Later, in the 1980s, this meteorite is identified as one of a small group originating from Mars. There are currently 16 meteorites from Mars . These were formerly classed as "SNC meteorites", refering to the places where typical meteorites of their kind where found (Shergotty-Nakhla-Chassigny); however, now the term "Martian meteorites" is preferred because some recent meteorites, most notably the oldest one, ALH84001, cannot be accurately classified as SNC. What's certain, however, is that that dog was really unlucky.

1911 "Martians Build Two Immense Canals in Two Years" (New York Times, Aug 27)

1911: "Frost on Mars"--Lowell (New York Times, Nov 10)

1911 A Princess of Mars, the first of eleven "John Carter on Mars" novels, is published. The author, Edgar Rice Burroughs, uses Schiaparelli's nomenclature and some of his Martians have green skin.

Svante Arrhenius, a Nobel Prize-winning chemist, suggests that certain minerals known as hygroscopic salts might be responsible for changes in the surface markings on Mars. Such salts absorb water and can show dramatic darkening on contact with it. His ideas fail to find support.

Burroughs' Princess of Mars is serialized in All-Story magazine.

The Panama Canal is completed.

Autumn: The first performance of Gustav Holst's (1874-1934) The Planet Suite at a private concert conducted by Adrian Boult. In March of 1913, Holst received an anonymous gift which enabled him to travel to Spain with Clifford Bax, the brother of the composer Arnold Bax (and later the librettist for Holst's opera The Wandering Scholar). Clifford Bax was an astrologer, and Bax introduced Holst to the concepts of astrology, which inspired him to compose The Planet Suite. The traditional order in performance of Holst's suite is: Mars, Venus, Mercury, Jupiter, Saturn, Uranus and Neptune. Holst considered this as a progression analogous to going through life. There is no piece for Pluto because this planet was not discovered until 1930. The Mars piece is called "Mars, the Bringer of War". However, "Jupiter, the Bringer of Jollity" is perhaps most people's favorite music from the suite. The first complete performance was under Albert Coates in Queen's Hall, London, in 1920.

In the spring, Guglielmo Marconi announced that several of his radio stations were picking up very strong signals "seeming to come from beyond the earth". Nikola Tesla, another prominent inventor, believed these signals were coming from Mars.

Estonian astronomer, Ernest Julius Opik (1893-1985), from his work on meteors, accurately predicts the frequency of craters on Mars many years before they could be ascertained.

Donald Menzel, at Lowell Observatory, concludes that air pressure on Mars would be less than 66 millibars (about 1/15 that of Earth) from studying photos of Mars taken in different wavelengths of light. He also notes that under different assumptions this upper limit would be 26 millibars (1/39 that of Earth). (Note: actually the average air pressure on Mars is about 6 millibars, 1/170 that on Earth, which is 1013 millibars).

Walter S. Adams correctly determines that Mars is "ultra-arid" by studying spectral lines.

William Coblentz (1873-1962) and Carl Lampland measure large day-night temperature differences are measured on Mars . This implies a thin atmosphere. Their measurements of the temperatures on Mars [wrongly] suggested that the equator is near 15-30 C, while the pole is near -50 to -70 C. Such temperatures are rather similar to Earth. Consequently, the measurements did much to encourage the belief in Martian life right up until space exploration of Mars. (Coblentz, W., and Lampland, C. "Further radiometric measurements and temperature estimates for the planet Mars", Scientific Papers of Nat. Bur. Studies, Vol. 22, 237-276)

Bernard Lyot at the Meudon Observatory near Paris concludes from polarimetric data that an upper limit to the atmospheric pressure on Mars is about 24 millibars.

La Planète Mars, 1659-1929, by Eugenios M. Antoniadi, is published (Herman et Cie, Paris). This is a complete and representative summary of the surface of Mars based on telescope observations. Antoniadi was an astronomer at the Meudon Observatory near Paris who produced maps of Mars that were some of the best available up until the 1950s.

Attempts to detect oxygen on Mars fail.

October 30: A dramatized version of The War of the Worlds is broadcast by Orson Welles on American radio, which has Martians landing at Grovers Mill, New Jersey. It is estimated that 6 million people listened to the show, and despite repeated announcements that it was a play, at least 1 million people thought it was real.

Earl Slipher photographs Mars in opposition and reports in 1940 that there are many canals. In contrast, George Ellery Hale, who used a 60 inch reflector at Mt Wilson says that no canals can be seen.

Carbon dioxide, but no oxygen, is detected by Gerard Peter Kuiper (1905-1973) on infrared spectrograms. Kuiper deduces that the Martian atmosphere contains twice as much carbon dioxide as the Earth's. For two decades, other than water vapor, carbon dioxide remained the only known constituent of the Martian atmosphere, although it was presumed to be a minor constituent rather than the major constituent that it really is.

1947 Das Mars Projekt (Mars Project) consisting of 10 ships and 70 crewmembers is proposed by Werner von Braun (1912-1977). This fleet of ten ships would go to Mars, explore, and return in about 520 days. The ships would be assembled in high orbit above the earth. The ships were then to take a long elliptical orbit around the sun, eventually reaching the orbit of Mars. There, "landing boats" would descend to Mars. Afterwards, the party would board seven of the ships, go into an elliptical orbit around the sun until reaching Earth's orbit, where rockets would slow them back down.

Lichens are proposed as a possible form of life for Mars. Conditions seem too harsh for more complex forms of life.

The Martian Chronicles by Ray Bradbury is published. It has since been reprinted repeatedly (64 editions as of 1985). Some of the stories contained within the book had been published as early as 1946.

Jan 28: The Los Angeles Times reports that the Japanese astronomer Sadao Saeki has seen a huge explosion on Mars on Jan 16 which produced a mushroom cloud 1450 km in diameter "like the terrific explosion of a volcano". No other people observed this explosion.

A global dust storm grows on Mars. The storm begins on August 20 with a bright cloud over the Hellas-Noachis region that spreads to engulf the whole planet by mid-September.

The Space Age begins with the Soviet launch of Sputik 1 , an Earth-orbiting satellite, on October 4.

Werner von Braun considers the "Mars Project" to be 15-20 years away.

Hyron Spinrad and co-workers report measurements of water in the atmosphere of Mars from spectroscopic observations. A column abundance of 14 +/- 7 precipitable microns is determined. "Precipitable microns" measures the the depth of water that forms if all the water in the atmosphere were condensed out onto the surface (1 micron = 1 millionth of a meter). 14 preciptable microns is less than one thousandth of the water typically in the atmosphere above the Sahara desert. Thus the Martian atmosphere was determined to be extremely dry.

Lewis Kaplan reports that the pressure of carbon dioxide on Mars is low, about 4 millibars, from analysis of the same spectra as Hyron Spinrad.

July 15: Mariner 4 flyby of Mars -- the first successful space probe to study Mars. Space exploration of Mars begins.

The contents of this webpage were compiled by Paul Karol and David Catling in 1996. We hope you appreciated this historical survey of Mars.