c.m. rodrigue, 2015 geography, csulb mars: history of exploration geography 441/541 geography of...

C.M. Rodrigue, 2015Geography, CSULB

Mars: History of Exploration

Geography 441/541Geography of Mars

S/15Dr. Christine M. Rodrigue


Mars: History of Mars Exploration

History of Earth-based Mars exploration The eyeball era

Ancient astronomer/astrologers noticed that five stars wandered: astra planeta

Mercury Venus Mars Jupiter Saturn




Indians described a Mars retrogation in 3,010 BCE




Chaldean database: Enuma Anu Enlil, which date back to 652 BCE and

continued until 60 BCE. Sample entry: "That month, the equivalent for 1 shekel of

silver was: barley [something missing] kur; mustard, 3 kur ... At that time, Jupiter was in Scorpio; Venus was in Leo, at the end of the month in Virgo; Saturn was in Pisces; Mercury and Mars, which had set, were not visible."




Chinese dynastic historians Interested in planetary conjunctions, including those

involving Mars Trying to correlate with events on Earth These records go back to the fourth century BCE




Mayans developed elaborate calendars Date back from 1800 BCE to the time of Columbus Heyday was from 250 to 900 CE Spanish destroyed most of their written records but a few

of the priestly codices or handbooks survive The Dresden Codex includes a "Mars Beast Table" that

predicts Mars' motions and retrogations




Ancient Greeks really bugged by retrogations Here’s one for Mars for June through November 2003




Ancient Greeks try to process the behavior of the planets: Aristotle (~384-322 BCE) saw an occultation of Mars by the

Moon and figured out Mars had to be farther from Earth than the Moon

Aristarchus (~310-230 BCE) developed heliocentric theory of the solar system and that the fixed stars had to be really, really far away

Hipparchus (~190-120 BCE) described the five planets' orbits as "deferents" around the earth

Ptolemy (~90 – 168 CE) added epicycles to handle retrogations The collapse of Graeco-Roman civilization in the fifth century

CE put an end to work on Mars or any other science for a long time: The Dark Ages




Ptolemy’s epicycles




Rise of Islam in the 7th century CE rejuvenated Arab culture and work on math and science

Greek and Roman classics were revived and extended Indian and Persian work on the modern numeric system

was adapted by the Arabs: Arabic numerals Algebra was elaborated (al-Jabr) Ibn al-Haytham around the 10th century and Nasir ad-

Din at-Tusi in the late 13th century revised Ptolemy’s epicycle system to make it better able to handle Mars’ and other planets’ retrogations

These developments brought to Europe, partly due to the Crusades




Europeans, inspired by rediscovery of the classics and the writings of the Arab scientists got into the swing of empirical science, too

Copernicus in 1543 revives Aristarchus’ heliocentrism: Earth rotates around a N/S axis It and the OTHER 5 planets revolve around the Sun in

perfect circles He had to keep Ptolemy’s epicycles to account for

retrogations Tycho Brahe (1546 to 1601), instrument engineer and

disciplined observer of the night skies, created databases of his team’s observations and focussed a lot on Mars due to its difficult pattern of motion




Johannes Kepler Went to study with Tycho Brahe and they began to fight: Kepler

was intrigued by Copernicus’ heliocentric theory and Brahe thought it was nuts

Brahe withheld his database from Kepler as a result, only letting him see the Mars data, which he thought was so difficult that it would keep Kepler out of trouble

Kepler found that the best way to make sense of Mars' orbit was to apply Copernicus' heliocentric theory but relax the assumption about a perfectly circular orbit

There’s speculation that he might actually have offed Brahe in 1601 to get his data!

He published his three laws of planetary motion in 1609




Kepler’s First Law of Planetary Motion: Planetary orbits are ellipses, not circles, with the Sun at one of the two foci of each ellipse




Kepler’s Second Law of Planetary Motion: The line connecting the planet to the Sun sweeps out equal areas in equal times




Kepler’s Third Law of Planetary Motion: The ratio of the squares of two planets’ revolutionary periods is the same as the cubes of their semimajor axes. The period a planet requires to go around the Sun increases rapidly with the radius of its orbit.



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.




Francisco Fontana, Italian astronomer, used a telescope to observe Mars in 1636 and made a sketch map (left), 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)




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)




Christiaan Huygens in 1656 saw a blank dot (dust storm?)

In 1659, though: He saw a dark mass,

probably Syrtis Major Hesaw 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?




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 he 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




In 1719, Giacomo Maraldi (Cassini’s nephew), noted changes in the white and dark spots

He inferred that Mars must have seasons


Mars: History of Mars ExplorationHistory 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




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




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



History of Earth-based Mars exploration The Geographic Period: Telescopes plus maps

William 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

day: 24 hours 37 minutes 22.6 seconds



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 their prime meridian!



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


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 He assigned names to honor famous Mars explorers He also pinpointed the prime meridian of Beer & Mädler to the crater we

use today (Airy)



The Geographic Period: Telescopes plus maps The Proctor toponymy was followed by others, including Camille

Flammarion's Mercator projected map of 1876.



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”




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!)




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




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


Peach Map 2007




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, Chloe Angeline Stickney Hall, kept after him, and he found them.

In gratitude, he named the biggest crater on Phobos for her: Stickney

Interesting areotidbit: Jonathan Swift’s 1726 Gulliver’s Travels had the astronomers of Laputa talk about Mars’ two moons!



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



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




Schiaparelli’s map, different projection


Schiaparelli 1884




1892 saw some important questions raised: William Pickering of Harvard was seeing these Schiaparelli

channels, too, but he saw one running across "Mare Eruthraeum" : 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.




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



The Geographic Period: Telescopes plus maps … plus speculation Lowell published maps, with canals aplenty


Lowell 1905: Canali to Canals




plus speculation Lowell began to encounter resistance from the increasingly

skeptical scientific community Alfred Russell Wallace measured the light spectra from

Mars and concluded that the place was really, really cold, about -35° F, so Lowell's claim of water canals had to be "all wet”

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




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



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


Canals in 1962 Air Force Map by Slipher, Used to Prepare for Mariner!

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