Download
1 / 50
500 likes | 768 Views
Mars—Roman God of War. Son of Juno and Jupiter , and lover of Venus . The most prominent of the military gods worshipped by the Roman legions . Festivals held in March . The word Mars is most likely the Latinized form of the Etruscan agricultural god Maris .
E N D
Mars—Roman God of War • Son of Juno and Jupiter, and lover of Venus. • The most prominent of the military gods worshipped by the Roman legions. • Festivals held in March . The word Mars is most likely the Latinized form of the Etruscan agricultural god Maris. • Mars originally a Roman god of fertility and vegetation and a protector of farmers and agriculture. • Marslater associated with battle as the Roman Empire expanded. Came to be identified with the Greek god Ares. • Unlike his Greek counterpart, Mars was revered and rivaled Jupiter as the most honored god. • He was also the tutelary god of Rome—regarded as the legendary father of Romulus. All Romans believed they were descendants of Mars. Mars & Venus—Make love…not war!
Mars global Surveyor Image—1998 Martian Face—Viking Orbiter 1976
Question • The so-called “canals” that Schiaparelli reported seeing upon the surface of Mars were actually ________. • an illusion caused by viewing the surface through a telescope with poor resolution • river valleys, caused by massive floods early in Mars's history. • an extensive rail network for the super trains that Martians developed for public transportation. • lines of volcanoes along faults in the Martian surface. • not a natural surface feature but a system of waterways designed to carry water from the poles to the equator built by a civilization suffering from increasing drought.
Martian Craters • Syrtis Major seen by Christian Huygens in 1659! • HellesPlanitia impact 5 x Texas!
Martian Topography—Laser ranging by Mars Global Surveyor • Northern lowlands—Southern Highlands—why?
Martian Crustal Dichotomy • Endogenic: Single-celled mantle convection—material rising in southern hemisphere—falling in northern • Impact: Single impact in northern hemisphere (…would be largest impact in Solar System!)
Like Texas—only a little taller! Olympus Mons—Top View About 3 ‘Everests High!
Question • The huge volcano Olympus Mons on Mars and those that make up the Hawaiian Islands on Earth appear to be very similar, but they differ in one important respect. What is this difference? • Olympus Mons isn’t on Mars … it’s a mountain along Utah’s Wasatch front. • Olympus Mons is formed almost solely of sulfur, whereas the Hawaiian Islands are formed of rock from the solidification of lava. • Olympus Mons is a very steep-sided volcano, whereas the volcanoes of Hawaii are rather flat, with gentle slopes right up to their calderas. • In the Hawaiian Islands, plate tectonic motion has moved the Pacific Ocean floor over a hot spot, forming a line of volcanoes. No such motion occurred for Olympus Mons over an equivalent hot spot on Mars.
Water on Mars? • Mars Odyssey • measurement of neutrons generated by cosmic rays. • Deficit indicates water… or ice. • Works down to a depth of 1 meter.
Spirit Landing site Gusev Crater—dusty, volcanic rock—no evidence of H2O
Opportunity Landing Site Sinus Meridianii— Mars Global Surveyor thermal imaging spectrometer found a strong signature of hematite…send Opportunity to investigate • One of flattest places in Solar System • Once a lake bed?
Martian ‘Blueberries’ Hematite BB-sized spheres of a type of iron oxide that forms when water runs through sedimentary rock Utah Blueberries Found in Zion and Capitol Reef national parks, Grand Staircase-Escalante National Monument, Snow Canyon State Park and the Moab area.
Martian Gullies • Image of gullies inside Newton Basin on Mars taken by Mars Global Surveyor 2003 • Slopes face away from sunlight. Most of the gullies occur at latitudes between 30o and 70o on the walls of pits developed in the south polar pitted plains.
Question • What evidence supports the hypothesis that large quantities of water once flowed on the planet Mars? • Frost that formed on the Viking spacecraft as it cooled after losing the heat that it accumulated during its descent to the Martian surface. • Frozen but dust-covered lakes found inside ancient craters. • Anetwork of giant canals linking polar and equatorial regions. • Channels that appear to have been ‘cut’ by running water and also surface features that look like deep, winding canyons and flood plains. • The two Martian landers, Spirit and Opportunity, were halted during their exploration of a Martian crater when they bogged down in deep mud.
Atmospheres Generated By Volcanic Outgassing … or Heavy Cometary Bombardment Mount St Helens… …not Mars!
CO2 Cycle on Earth • What happens if it starts to warm up on Earth? • What happens if it starts to cool down?
Notice… • No inversion! • Why?
No CO2 Cycle on Mars • Did Mars have liquid H2O early on? • What happened to volcanic activity on Mars? • What removes CO2 from the atmosphere … puts it back in? • What happened to liquid H2O on Mars?
Question • Ironically, liquid water that once existed on the surface of Mars, absorbed CO2 in its atmosphere, which _____. • carbonated the water and turned it into steam, which escaped the planet. • turned the water into a corrosive acid that killed all emerging life forms. • reduced the strength of the greenhouse effect required to keep Mars warm enough for the water to remain liquid. • thirsty Martians drank because they loved carbonated water. • … all of the above.
Mission Cost: 1.5 G$ • Experimental Package: • Weight Limit: 15 kg • Size Limit: 1 cubic foot
The Experiments: 1. LR (Labeled Release) • Based upon searching for biological contaminants in city water supplies • Martian organisms would ‘eat’ organic nutrients—produce CO2, CH4, HS a burst of gas production when the medium was first added But not when the soil had been preheated to kill off any microorganisms it might have contained. However, gas production did not increase as time went on (as would be expected if living organisms were growing in the medium) Later additions produced no additional gas. • Bath Martian soil sample in solution containing 7 organic compounds tagged with C14 and S35 — radioactive isotopes of carbon and sulfur • Analyze gasses surrounding sample for presence of C14 and S35 • the gas was produced by nonliving chemistry brought about by oxidizingagents (H2O2) in the soil.
2. GEX (Gas EXchange) • Surround Martian soil with a known mixture of gasses—see if surrounding atmosphere changes • Stimulate metabolic activity of ‘dormant’ organisms by letting water vapor containing 19 organics breath through the soil—see if surrounding atmosphere changes • Analyze atmosphere with Gas Chromatograph • Rapid release of large amounts of O2 and smaller amounts of CO2 which subsided. • More nutrient broth added; this time directly to the soil. • Another, smaller, release of CO2 but no release of O2. • The conclusion: the gases were formed by nonbiological chemistry (oxidizing agents again).
3. PR (PyrolyticRelease) • Surround soil with CO2 and CO brought from Earth—C tagged with C14. • Heat soil to 750 C—break apart any organic matter that had incorporated C14 in its structure • Organic matter detected in 7 of 9 runs. • However, some positive results achieved even on runs where the soil had first been heated to such a high temperature that any microorganisms present would have been killed. • Introduced atmosphere containing radioactive CO2 and CO was not completely purged before analysis.
GCMS (Gas Chromatograph/Mass Spectrometer) • Measure organics in Martian soil and atmosphere directly • Heat soil to 500 C—pass vapors through GCMS • The most sensitive and direct experiment • No organic matter present at level of a few parts per billion! • … the results of LR and GEX experiments generated false positives due to H2O2 in Martian soil, contamination of PR experiment with fluids in landing gear.
ALH 84001 1st Meteorite found in 1984 Expedition to Allan Hills, Antarctica SNC meteorite—Stony Achondrite First found: Sherghati, India (1865) El-Nakhla, Alexandria, Egypt, (1911) Chassigny, Haute-Marne, France (1815) Yes… From Mars! This ‘Snicker’ from Mars? • Chemical composition • Trapped gasses
History of ALH84001 Age of meteorite: 4.5 Billion yrs—when rock 1st cooled—Rb-Sr dating. Age of carbonite globules: 3.6 Billion yrs—when Martian crust was ‘shocked’ into fragments by meteorite impact. Cosmic Ray Exposure Age: 16 Million yrs—rock fragment ejected from Mars during 2nd nearby impact. ‘Terrestrial Age’: 13 Thousand yrs—ALH84001 lay in Antarctica—C14 dating (C14 formed in space by cosmic rays).
Evidence of Martian Life? • Carbonate Globules containing magnetite, greigite, pyrrotite. • Claim: • Carbonate globules formed in H2O. • Minerals bear strong resemblance to mineral alterations caused by primitive bacteria on Earth. • PAH’s found—higher concentration on inside. • Claim: • When micro-organisms die they break down into PAHs • SEM microscopy revealed tiny "ovoids" 20–100 nm • claim: • ‘nanofossils’— fossil remnants of tiny bacteria
Non-Biological Explanations (i) Carbonate globulesformed at high temperature >1200o F (ii) Mineral grains can be formed by non-biological processes (iii) Magnetite, pyrrohite, greigite…can be produced on Earth by magnetotactic bacteria, but Mars has no magnetic field! (i) PAH’s found on other meteorites and dust grains in space (ii) PAH’s produced on Earth by non-biological sources, eg, fire. … But, to be fair, these PAH’s not like others … still no convincing proof that they were produced by biological activity (i) fossils 100 x smaller than smallest known Earth bacteria! (ii)Even smaller than recently discovered ‘nanobacteria’ (iii) too small to store ‘information’ (iv) artifacts of sample preparation process Extraordinary claims require extraordinary evidence—Carl Sagan
Question • The exploratory life-science experiments on board the Viking spacecraft lander found evidence _______. • of very reactive chemistry in the Martian surface rocks but no unequivocal evidence of life or remnants of life-forms • that primitive life-forms existed on Mars in its early history but that they did not survive • That Orson Welles’ 1938 radio broadcast of ‘War of the Worlds’ should have been taken more seriously • of a sterile environment and a chemically inert soil in which life could not have existed • of primitive life-forms such as elementary bacteria, which could constitute a hazard for human exploration of Mars
Martian Moons—Fear and Panic • Phobos (Fear): • Orbital Radius: 9378 km • Orbital Period: 7 hr 39 min Where will Phobos rise and set? • Deimos (Panic): • Orbital Radius: 23,460 km • Orbital Period: 30 hr 18 min • Almost synchronous
How the advent of the space age transformed our understanding of Mercury, Venusand Mars Summary of Mercury, Venus, Mars • What astronomers have learned by observing the terrestrial planets from Earth • The outstanding features of Mercury, and why its magnetic field came as a surprise • The different ways in which Mercury, Venus, and Mars rotate on their axes • The strange relationship of Venus’ rotation and orbital period to that of the Earth
The possibility that life once existed on Mars Summary of Mercury, Venus, Mars • How geologic activity took a very different course on Venus than on Earth, and why it essentially stopped on Mars • The key differences among the atmospheres of Earth, Venus, and Mars • How the atmospheres of Earth, Venus, and Mars evolved to their present states • The evidence that there was once liquid H2O on Venus and Mars • What we know about the two small satellites of Mars
