Mars: History of Exploration II

1. Mars: History of Exploration II Geography 441/541 Geography of Mars S/19 Dr. Christine M. Rodrigue C.M. Rodrigue, 2019 Geography, CSULB

2. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The telescope era Galileo Galilei (1564-1642) In 1609, he built and began using a telescope He observed Mars in order to test Copernicus’ and Kepler’s predictions that the planets should show phases His telescope was too primitive, so he honestly reported he couldn’t see Martian phases but that Mars didn’t look perfectly round For his defense of Copernicus' heliocentric theory against specific orders of the Church, Galileo got into trouble with the Inquisition and was ordered into prison, a sentence later commuted to lifelong house arrest.

3. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The telescope era • Francisco Fontana, Italian astronomer, used a telescope to observe Mars in 1636 and made a sketch map, the first ones recorded • He could clearly see that Mars was in gibbous phase, as Copernicus, Kepler, and Galileo expected (right) • The "very black pill" he observed in the center might have been Syrtis Major – or a flaw in his telescope (he saw a "pill" on Venus, too) C.M. Rodrigue, 2019 Geography, CSULB

4. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The telescope era • The phases business (images from www.astro-tom.com) • Moon: all phases (new, crescent, quarter, gibbous, full) • "Inferior" planets (all phases) • "Superior" planets (only gibbous or full) C.M. Rodrigue, 2019 Geography, CSULB

5. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The telescope era • Christiaan Huygens in 1656 saw a blank dot (dust storm?) • In 1659, though: • He saw a dark mass, probably Syrtis Major • He saw it rotated around a N/S axis • He figured its day length is very much like Earth’s • He left sketch maps, including one showing a polar cap? C.M. Rodrigue, 2019 Geography, CSULB

6. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The telescope era • Jean Dominique Cassini estimated Mars' day at 24:40 • He observed bright spots at the poles and dark spots along the equator in the 1660s • In 1672, he and a friend simultaneously observed Mars from different places on Earth and used parallax to figure Mars’ distance from Earth • Applying Kepler’s 3rd law, he used this Mars distance to figure out how far Earth was from the Sun C.M. Rodrigue, 2019 Geography, CSULB

7. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The telescope era In 1719, Giacomo Maraldi (Cassini’s nephew), noted changes in the white and dark spots He inferred that Mars must have seasons

8. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The telescope era In 1783, William Herschel also saw these changes with an advanced reflecting telescope Using rotation of light and dark spots, he determined Mars’ axial tilt at ~25, which is the mechanism for seasonality He figured dark areas were seas and light areas clouds He thought the polar light spots were thin snow and ice caps Faint stars that passed close to Mars were not dimmed, so he inferred that Mars had a very thin atmosphere

9. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The telescope era In 1809, Honoré Flaugergues spotted variations that he described as “yellow spots” on the surface of Mars He had been trying to time certain small darker spots across the martian disk, hoping to refine the estimates of Mars' day length, when he noticed some of the features seemed to move in a manner inconsistent with a solid feature anchored to the surface He didn't know what they were but wondered if they were some atmospheric phenomenon It may be possible that he saw one of Mars' massive dust storms (though some argue that his telescope didn't have that kind of resolving power)

10. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The telescope era • As telescopes improved by leaps and bounds, sketches of Mars did, too • In 1800, Johann Hieronymus Schroeter made drawings of Mars. • These sketches are becoming closer to formal maps C.M. Rodrigue, 2019 Geography, CSULB

11. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps • Wilhelm Beer and Johann H. von Mädler collaborated to map regularly seen features on Mars, thinking those might be permanent geological features • They used the first “areographic grid,” which is close to today’s (1841) • They also refined Cassini's refinement of Huygens' estimate of the Martian sidereal day: 24 hours 37 minutes 22.6 seconds C.M. Rodrigue, 2019 Geography, CSULB

12. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps • The Beer and Mädler maps and their areographic grid mark the advent of true Mars cartography and a new era of Mars exploration • We still use something very close to their prime meridian! C.M. Rodrigue, 2019 Geography, CSULB

13. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation In 1854, William Whewell speculated that there might be Martian life He wondered if there are greenish seas and red landscapes Geotidbit: Whewell was the person who in 1835 first coined the word, “scientist” (instead of “natural philosopher”) to describe someone, Mary Somerville, a geographer who wrote the first physical geography textbook in 1848, a book used until the early 20th century!

14. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps • Richard Proctor projected the drawings of William Dawes onto a stereoscopic projection using the Beer & Mädler grid (1867) • He assigned names to honor famous Mars explorers • He also pinpointed the prime meridian of Beer & Mädler to the crater we use today (Airy) C.M. Rodrigue, 2019 Geography, CSULB

15. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps • The Proctor toponymy was followed by others, including Camille Flammarion's Mercator projected map of 1876. C.M. Rodrigue, 2019 Geography, CSULB

16. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation In 1863, Italian Jesuit monk Angelo Secchi drew a map and called the dark areas “canali” (translatable as “channels” or ...”canals”) The dark triangle of Syrtis Major he dubbed the “Atlantic Canal”

17. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation In 1860, Emmanuel Liais suggested that the dark areas might be vegetation, changing with the seasons In 1873, Camille Flammarion agreed that Liais might be on to something, adding that maybe the red color itself is the color of the vegetation (funny, given how red is assigned to represent green in false color imagery these days!)

18. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation Also in 1867, Pierre Jules Janssen and Sir William Huggins experiment with a spectroscope, training it on Mars to generate spectra of reflected light and absorption lines. They hoped to detect water vapor and oxygen but reported not finding any

19. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation So, by the mid 1870s, there’s all sorts of exciting speculation about Mars, stimulated by the ever-increasing resolution of telescopes: canali, dark seas, snowy polar caps, vegetation It was known that the opposition of 1877 was going to be one of the best in decades, and everyone was looking forward to a great viewing opportunity coupled with the great new telescope capacity

20. C.M. Rodrigue, 2019 Geography, CSULB Peach Map 2007

21. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation 1877 was a great opposition: Asaph Hall discovered the two moons of Mars, Phobos and Deimos (Earth had one, Jupiter had four; therefore, Mars HAD to have two) He had given up but his wife, Angeline Stickney Hall (a suffragist and mathematician), kept after him, and he found them. In gratitude, he named the biggest crater on Phobos for her: Stickney Interesting areotidbit: Jonathan Swift’s 1726Gulliver’s Travels had the astronomers of Laputa talk about Mars’ two moons! Another one: Voltaire, in “Micromégas,” a short story he wrote in 1752, had two aliens discussing the two moons of Mars!

22. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps … plus speculation • The US Naval Observatory Telescope that Hall used (still in service) • Phobos’ and Deimos’ orbits were worked out C.M. Rodrigue, 2019 Geography, CSULB

23. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps • 1877 opposition was the basis of Giovanni Sciaparelli’s maps of the light and dark areas of Mars … and those linear features he, too, called “canali” • Note the new toponymy: place names from mythology C.M. Rodrigue, 2019 Geography, CSULB

24. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps • Schiaparelli’s map, different projection C.M. Rodrigue, 2019 Geography, CSULB

25. C.M. Rodrigue, 2019 Geography, CSULB Schiaparelli 1884

26. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps 1892 saw some important questions raised: William Pickering of Harvard was seeing these Schiaparelli channels, too, but he saw one running across "Mare Erythraeum" : How could a “canal” run across a “sea”? He wondered if maybe the dark areas represent vegetation. Edward Emerson Barnard spotted craters on Mars. No-one else paid much attention. He also said he tried and tried to see all these canals and couldn't for the life of him.

27. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation 1893: Someone gave Percival Lowell a book about Mars by Camille Flammarion (la planète Mars): instant obsession Unlike most of us who get obsessions, he had $$$$$! He built and staffed the Lowell Observatory in AZ In 1902, appointed at MIT as non-resident astronomer He published Mars in 1885, Mars and Its Canals in 1906, and Mars, the Abode of Life in 1908

28. Mars: History of Mars Exploration • History of Earth-based Mars exploration • The Geographic Period: Telescopes plus maps … plus speculation • Lowell published maps, with canals aplenty C.M. Rodrigue, 2019 Geography, CSULB

29. C.M. Rodrigue, 2019 Geography, CSULB Lowell 1905: Canali to Canals

30. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation Lowell began to encounter resistance from the increasingly skeptical scientific community Alfred Russell Wallace argued the light spectra from Mars showed no signs of water vapor in the atmosphere and the place was really, really cold, about -35° F, so Lowell's claim of water canals had to be "all wet” (1907) Svante Arrhenius argued in 1912 that Mars might be covered with salts that change color with saturation and desiccation: No life necessary Other scientists reported having trouble seeing canals

31. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation Lowell responded by turning to popular audiences, shunning the peer review that is central to science Public lectures, popular magazine stories His stories became more extreme Other scientists began to shy away from Mars A few, however, were caught up in Lowell’s beliefs: Nikola Tesla claimed to detect radio signals from Mars in 1899 Guglielmo Marconi, of radio fame, also claimed to have heard from an alien radio transmitter

32. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation The 60” Hale Telescope at Mt. Wilson turned up nary a canal In 1913, Edward Maunder did a psychological experiment showing how the human eye tends to see patterns linking random lines and circles and the farther the observer was from the random pattern, the more likely they were to report linearities linking things in the pattern Lowell died in 1916, knowing that the scientific community thought Mars was not only uninhabited but uninhabitable A few hardy souls held out for canals until Mariner As late as 1962, maps used for Mariner mission planning still showed canal-like streaks (Slipher)! Canals and the dying Mars motif common in science fiction

33. C.M. Rodrigue, 2019 Geography, CSULB Canals in 1962 Air Force Map by Slipher, Used to Prepare for Mariner!

34. C.M. Rodrigue, 2019 Geography, CSULB Mars: History of Mars Exploration History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps … plus speculation For a wonderful Google Earth Mars based treatment of the whole Mars canals thing, check out the Adler Planetarium exhibit: https://artsandculture.google.com/exhibit/4ALy3KSjVtBnJw