c.m. rodrigue, 2007 geography, csulb mars: history of exploration geography 494-01 s/07 dr....

C.M. Rodrigue, 2007Geography, CSULB

Mars: History of Exploration

Geography 494-01

S/07

Dr. 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 Algebra and the Arabic numerals were developed 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 publishes 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 builds and begins 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, uses a telescope to observe Mars in 1636

He can clearly see that Mars was in gibbous phase, as Copernicus, Kepler, and Galileo expected

He makes the first drawings of Mars, in full and gibbous phases




Christiaan Huygens in 1659 got such a good look at Mars:

He sees it rotates around a N/S axis

He figures its day length is very much like Earth’s

He left a few sketches




Jean Dominique Cassini observes bright spots at the poles and dark spots along the equator in the 1660s

In 1672, he and a friend simultaneously observe Mars from different places on Earth and he uses parallax to figure Mars’ distance from Earth

Applying Kepler’s 3rd law, he uses this Mars distance to figure out how far Earth was from the Sun




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

He infers that Mars must have seasons




In 1786, William Herschel also saw these changes He was able to determine Mars’ axial tilt at ~25 from the

ecliptic, 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 He saw that faint stars that passed close to Mars were not

dimmed, inferring that Mars had a very thin atmosphere



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

As telescopes improved by leaps and bounds, sketches of Mars did, too In 1800, Johann Hieronymus Schroeter makes drawings of Mars.




William Beer and Johann H. von Mädler assembled the first real map of Mars in 1840

They use the first “areographic grid,” which is close to today’s 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 …

plus speculation In 1854, William Whewell speculates that there might be

Martian life He wonders if there are greenish seas and red landscapes




plus speculation In 1863, Jesuit monk Angelo Secchi draws a map and calls

the dark areas “canali” The dark triangle of Syrtis Major he dubs the “Atlantic Canal”




plus speculation In 1860, Emmanuel Liais suggests that the dark areas might

be vegetation, changing with the seasons In 1873, Camille Flammarion agrees that Liais might be on to

something, adding that maybe the red color itself is the color of the vegetation



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

speculation In 1867, Richard Anthony Proctor creates a map of Mars His pinpointing of the prime meridian is the one used today




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




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 Hall used (still in service) Phobos’ and Deimos’ orbits




1877 opposition was the basis of Giovanni Sciaparelli’s maps of the light and dark areas of Mars … and those linear features he called “canali”




Schiaparelli’s map, different projection – brownie point …




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”?

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 gives Percival Lowell a book about Mars by

Camille Flammarian: instant obsession Unlike most of us who get obsessions, he had $ He builds and staffs the Lowell Observatory in AZ In 1902, appointed at MIT as non-resident astronomer He publishes Mars in 1985, Mars and Its Canals in 1906,

and Mars, the Abode of Life in 1908


Mars: History of Mars Exploration History of Earth-based Mars exploration

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




plus speculation Lowell encounters 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 responds 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




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 dies 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



The Spectral Analysis era: A New Mars The electromagnetic spectrum can be displayed by wavelength



History of Earth-based Mars exploration The Spectral Analysis era: A New Mars

Spectral analysis in this context is the study of absorbed, emitted, and scattered radiation

A radiant object can emit wavelengths along the EMS at varying intensities: hot or dense objects emit across a continuous spectrum

Substances in the radiant object or between it and the sensor can absorb certain wavelengths

The wavelengths absorbed are diagnostic of particular minerals or elements or compound

Substances and surfaces also reflect particular wavelengths



History of Earth-based Mars exploration The Spectral Analysis era:

A New Mars Some reflectance spectra:

water, carbon dioxide, methane



The Spectral Analysis era: A New Mars Continuous spectra Emission line spectra Absorbtion line spectra

c.m. rodrigue, 2007 geography, csulb mars: history of exploration geography 494-01 s/07 dr....

Documents

csulb mars

based mars exploration

mars motions

mars retrogation

occultation of mars

mars beast table

rodrigue slide

century bce slide