101 The Solar System Tuesday, Wednesday, Thursday

Tom Burbine [email protected]

http://www.daviddarling.info/images/Mars_large.jpg Mars

• Names after Mars, Roman God of War • Mars has two tiny natural , and , which orbit very close to the planet and are thought to be captured . • Both satellites were discovered in 1877 by Asaph Hall, and are named after the characters Phobos (panic/fear) and Deimos (terror/dread) who, in Greek mythology, accompanied their father Ares, God of War Phobos (~22 km diameter)

Taken by Mars Express Phobos Taken by Mars Reconnaissance Orbiter

Crater called Deimos (~12 km diameter) Percival Lowell (1855 -1916)

• Lowell produced intricate drawings of the Red Planet • Finding hundreds of straight lines (termed "canals")

He thought

• Lowell concluded that the bright areas were deserts and the dark were patches of vegetation • Lowell thought the canals were constructed by intelligent beings who once flourished on Mars. For years

• People thought life could exist on Mars and Venus, the closest planets to Earth However,

• Venus is extremely hot (~700 -800 K) • Atmospheric pressure is 90 times that of Earth What happened on October 30, 1938? What happened on October 30, 1938?

• http://sounds.mercurytheatre.info/mercury/381030 .mp3 Mars

• The average recorded temperature on Mars is -63 °C with a maximum temperature of 20 °C and a minimum of -140 °C • Atmospheric pressure is 1/100 of Earth’s • Mars is often enveloped by planet -wide dust storms Atmosphere

• Carbon dioxide 95.3% • Nitrogen 2.7% • Argon 1.6% • Oxygen 0.13% • Carbon monoxide 0.07% • Water vapor 0.03% • Nitric oxide 0.013% Dust Devils

• http://en.wikipedia.org/wiki/Image:Marsdustdevil2.gif Dust Devils

• Dust devils are smaller and weaker than tornadoes • They are caused by convection on hot, calm summer days. • Air near the surface becomes much warmer than the air above, creating an updraft.

Key to Life

• All life on Earth depends on water • So if you find water, you may find life Habitable Zone

• The region around a star in which planets could potentially have surface temperatures which liquid water could exist

In the past

• Mars appeared to be warmer and wetter Atmospheres

• Layer of gases that surround a body with sufficient mass • Gravity keeps the gases around the body Atmospheric Pressure • Pressure due to the weight of air above the measurement point • Pressure is force per unit area • Standard atmosphere is defined as being precisely equal to 101,325 Pascals where a Pascal is 1 N/m 2 • 1 bar = 100,000 pascals • Pressure in the solar nebula was ~10 -4-10 -8 bars Phase Diagram

http://img.search.com/thumb/d/dc/Phase -diag.png/300px-Phase-diag.png Mars

http://science.nasa.gov/headlines/y2000/ast29jun_1m.htm http://images.encarta.msn.com/xrefmedia/aedia/aencmed/targets/illus/cha/T073590A.gif http://www.splung.com/heat/images/phases/phasediagram.png Pressure Temperature

• Valles Marineris is a system of canyons located just south of the Martian equator. The system is about 4000 km long, Valles Marineris

• Most of the water is frozen (permafrost and polar caps) • No bodies of liquid water, which could create a hydrosphere • Only a small amount of water vapor is in the atmosphere How did Mars lose its water? How did Mars lose its water?

• One possibility: • On Earth, we're protected from the solar wind by a global magnetic field • Mars appears to have had a global magnetic field, which turned off • When it turned off, Mars’ atmosphere may have been eroded by the solar wind Hellas and Argyre basins, both thought to be about four billion years old, are demagnetized. Magnetic field must have turned off more than four billion years ago.

http://science.nasa.gov/headlines/y2001/ast31jan_1.htm Topography

• The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. • The surface of Mars as seen from Earth is consequently divided into two kinds of areas, with differing albedo.

MOLA

• MOLA is the Mars Orbiter Laser Altimeter on Mars Global Surveyor (MGS) spacecraft • This altitude determination process works by measuring the time that a pulse of light takes to leave the spacecraft, reflect off of the ground, and return to MOLA's collecting mirror. • By multiplying the reflection time by the speed of light, scientists are able to calculate Surveyor's altitude above the local terrain to within 30 meters (98 feet) or better. Two Hemispheres

• Northern Plains • Southern Highlands In September 1877, Italian astronomer Giovanni Schiaparelli used a 22 cm telescope to help produce the first detailed map of Mars. These maps notably contained features he called canali, which were later shown to be an optical illusion. http://upload.wikimedia.org/wikipedia/commons/d/dd/Karte_Mars_Schiaparelli_MKL1888.png • Percival Lowell map of Mars from ~1914

http://en.wikipedia.org/wiki/Image:Lowell_Mars_channels.jpg • Hubble image from 1999 http://en.wikipedia.org/wiki/Image:Mars_HST_Mollweide_map_1999.png

• blue is low • red/white are high • These two hemispheres are centered on the plateau (including the Valles Marineris and the large volcanos) and on the Isidis impact basin (with the Hellas basin to the south) Epochs (Ages) on Mars

• Epochs are defined by the number of impact craters on the ground surface • Older surfaces have more impact craters. Geologic History of Mars • epoch (named after Noachis Terra):

• Formation of the oldest surfaceurfaces of Mars, 4.6 billion years ago to 3.5 billion years ago. “Noachian age surfaces are scarred by many large impact craters.”s.” TheTh Tharsis bulge is thought to have formed during this period.

• Noachis Terra ("Land of Noah") is an extensive southern landmass (terra) of the planet Mars.

• http://www.google.com/mars/ Geologic History of Mars • epoch (named after Hesperia Planum) :

• 3.5 billion years ago to 1.8 billion years ago. The Hesperian epoch is marked by the formation of extensive lava plains.

http://www.psi.edu/NE_Hellas_Hesperia.jpg Geologic History of Mars • epoch (named after Amazonis Planitia)

• 1.8 billion years ago to present. Amazonian regions have few impact craters, but are otherwise quite varied. Olympus Mons formed during this period along with lava flows elsewhere on Mars.

http://upload.wikimedmedia.org/wikipedia/commons/7/7f/Amazonis_planitia_topo.jpg • The northern hemisphere is much flatter • The northern hemisphere was formed from lava flows • The northern hemisphere is also lower than the southern hemisphere, with an elevation difference between the two of about 5 km (3 mi) What caused this difference? What caused this difference? • Glancing impact – “The impact would have to be big enough to blast the crust off half of the planet, but not so big that it melts everything”

http://www.world -science.net/othernews/080625_mars.htm • Huge ocean covered Northern Hemisphere?

http://www.astrobio.net/news/article58.html Location of proposed shoreline with respect to Olympus Mons. Since the proposed cliff faces toward the smooth plains, it was suggested that this feature might be the signature of a cliff that forms from erosion by waves in a body of water as they break against a coastline. Olympus Mons

• The shield volcano, Olympus Mons ( Mount Olympus ), is at 26 km the highest known volcano and mountain in the solar system. Shorelines

No sign of a cliff cut by waves.

Viking Image Mars Orbital Camera (MOC) image from Mars Global Surveyer http://www.astrobio.net/news/article58.html Hellas Basin

9 km depth

2,300 km in diameter

http://upload.wikimedia.org/wikipedia/commons/f/fc/Hellas_basin_topo.jpg Hellas Basin

• It is the second or third largest impact crater and the largest visible impact crater known in the Solar System. Northern Polar Cap Crater is 80 m in diameter

Permanent ice cap comprised mainly of water and carbon dioxide ice http://en.wikipedia.org/wiki/Planum_Boreum Northern Polar Cap

• The perennial or permanent portion of the north polar cap consists almost entirely of water ice. • In the northern hemisphere winter, this gains a seasonal coating of frozen carbon dioxide (dry ice) about one meter (three feet) thick. Basic Definition of Life

• Growth • Metabolism • Motion • Reproduction • Stimulus response ALH 84001

• Allan Hills 84001 • found in Antarctica • Thought to have evidence for life (1996) Meteorites from Mars

• Are called SNCs • Shergottites, Nakhlites, Chassignites – Shergotty – Nakhla – Chassigny • 34 Martian meteorites currently known How do we know they are from Mars?

• Most have young crystallization ages (1.35 and 0.15 billion years) • Gases in glass in meteorites match Mars Crystallization Age

• Crystallization age is measured from when the rock cooled and the mineral formed • Certain unstable isotopes are locked into the crystals of the rock, and they begin to decay.

Evidence

• organic molecules

• Magnetite (Fe 3O4) that looks like it formed from biologic activity • nanofossil-like structures

Age of ALH 84001

• ALH 84001 - 4.5 billion years • But has same oxygen isotope ratio as other Martian meteorites so it comes from Mars • Oldest meteorites are 4.56 billion years

What are problems with studying Martian meteorites to learn about Mars • You don’t exactly where the Martian Meteorites come from Why Volcanoes are largerlar on other planets?

http://athena.cornell.edu/images/scientists/lava_flow_chart.jpg Look for evidence for processes that occur on surface of a planet • Geomorphology - scientific study of landforms and the processes that shape them – Important Questions: – Are features on Mars formed by volcanic processes? – Are features on Mars formed by water? • Compositional – Important Questions: – Are the compositions of minerals on Mars consistent with volcanic processes? – Are the compositions of minerals on Mars consistent with forming in the presence on Mars? • Are Features – due to volcanic processes or running water? • Are Rocks – contain minerals formed in volcanic processes (such as olivine or pyroxene) – Or affected by water (precipitates from solution or minerals containing water) Formed by Lava?

http://cdn.physorg.com/newman/gfx/news/hires/lavalikelyma.jpg • Martian basaltic meteorite • Looks like igneous rock Russell Crater Dunes

• Taken by Mars Reconnaissance Orbiter

http://blogs.discovermagazine.com/badastronomy/2010/04/12/new -evidence-of-transient- liquid-water-on-mars/ Compositional Effects of Water

• Examples:

• 2Fe 2SiO 4 + 4H 2O + O 2 → 2Fe 2O3 + 2H 4SiO 4 • olivine + water + oxygen → hematite + silicic acid

• Form CaSO 4·2H 2O (Gypsum, a sulfate) Terrestrial Analogs

• You can use terrestrial environments to look for analogs for processes that occur on Mars Face on Mars

http://www.guidescope.net/solarsys/mars_map2.jpg Significant Mars Missions • Viking 1 (1976-1982) (NASA) (Lander) • Viking 2 (1976-1980) (NASA) (Lander) • Mars Global Surveyor (1993-2006) (NASA) (Orbiter) • Mars Pathfinder (1997) (NASA) (Lander) • Mars Express (2003-present) (ESA) (Orbiter) • MER Spirit (2004-present) (NASA) (Lander) • MER Opportunity (2004-present) (NASA) (Lander) • Mars Reconnaissance Orbiter (2006 -present) (NASA) (Orbiter) • Phoenix (2008) (NASA) (Lander) Viking Missions

• Each spacecraft consisted of an orbiter and a lander • Viking 1 lander landed July 20, 1976 • Viking 2 lander landed September 3, 1976 • Total cost was ~1 billion

Viking 2 Red Color • The red color of the planet comes from the oxidation of iron minerals in the soil. • Fe 2+ is becoming Fe 3+

• Iron is shiny when it is not oxidized

• When it loses two electrons by encountering oxygen, it becomes black or green • When it loses three electrons by encountering oxygen, it becomes red • Rusting Viking 2

Four Experiments • There were results that were initially positive • But results could all be explained through non -biologic chemistry • For example, Labeled Release Experiment – The nutrients were tagged with radioactive 14 C 14 – Looked for emitted CO 2 gas as evidence for chemical reactions that happen in living organisms to maintain life – Radioactive gases were given off immediately for the first insertion of nutrients – Subsequent insertions did not givegi off radioactive gases Four Science Goals of NASA's long-term Mars Exploration Program:

• Determine whether Life ever arose on Mars • Characterize the • Characterize the • Prepare for Human Exploration Mars Pathfinder

• Landed July 4, 1997 • Weight - 870 kg • Lasted 3 months • Discovery Mission

Objectives of Mars Pathfinder

• Discovery Mission - To prove that the development of "faster, better and cheaper" spacecraft is possible (with three years for development and a cost under US $150 million). • To show that it is possible to send a load of scientific instruments to another planet with a simple system and at one fifth the cost of a Viking mission. • To demonstrate NASA's commitment to low -cost planetary exploration finishing the mission with a total expenditure of US$ 280 million, including the launch vehicle and mission operations.

APXS Radioactive Cu-244 AXPS – Alpha Proton X-ray Spectrometer • Radioactive Cu-244 source • Emits alpha particles (helium nuclei), protons, and X -rays • Measures the backscattered alpha particles and protons and emitted X-rays from the rock • Different elements interact with alpha particles, protons, and X-rays differentlyy

Sojourner Rover is investigating Yogi the Rock

The rock was the first on Mars found to be made of basalt The smoothness of the surface also suggested the past existence of water in the region. Yogi

Barnacle Bill

http://www2.jpl.nasa.gov/snc/a -mgsivsalsi5.gif

Spirit and Opportunity

• I used to live in an Orphanage. It was dark and cold and lonely. At night, I looked up at the sparkly sky and felt better. I dreamed I could fly there. In America, I can make all my dreams come true..... Thank-you for the "Spirit" and the "Opportunity"

— Sofi Collis, age 9

• Spirit landed in Gusev Crater – appeared basaltic (lava flows) • Opportunity landed on Meridiani Planum – appeared to have lots of sedimentary rock Spirit

http://en.wikipedia.org/wiki/File:Spirit_tracks.png Spirit

The Gusev crater with Ma'adim Vallis snaking into it

Rover tracks Made by the RAT – Rock Abrasion Tool

Rock called Adirondack

• Iron-rich sulfate salt • Seen when climbing Husband Hill Opportunity

Mars rover Opportunity just passed 12-mile mark

Opportunity Ledge

Rocks seem layered. Either due to sediments or volcanic ash Hematite (Fe 2O3) formed as deposits in water? Called blueberries

Mars water appears very salty

water -activity" value that indicates howow suitablesui a solution is for use by organisms Spirit and Opportunity - now

• Both completed their planned 90 -day missions • Both have completed over 2,100 days • Still functioning (Spirit is hibernating now) • Spirit has a broken wheel • Spirit is now stuck in soft soil • Opportunity’s shoulder joint on its robotic arm is broken Taken by Spirit

http://commons.wikimedia.org/wiki/File:PIA05547-Spirit_Rover -Earth_seen_from_Mars.png Mars Global Surveyor (1996 -2006) G

Gullies in Newton basin Mars Orbiter Laser Altimeter 2001 Mars Odyssey

• Hunts for evidence of past or present water and volcanic activity on Mars • Also used as a communications relay for the Mars Exploration Rovers and Phoenix

• Hydrogen in water slows down neutrons. • Instrument measures the energy of the neutrons • Water will produce excess low -energy neutrons

Concentrations of Chloride Salts Mars Express (2003-present) • Launched by the European Space Agency • Also had Beagle 2 lander Beagle 2 • Crashed on surface Mars Express confirmed the presence of Methane (CH4) on Mars Methane • Methane is quickly destroyed in the Martian atmosphere by sunlight, so its discovery indicates some ongoing process is releasing the gas • Organisms release much of Earth's methane as they digest nutrients. • However, it could also be released by volcanoes http://news.bbc.co.uk/2/hi/science/nature/7829315.stm Mars Reconnaissance Orbiter (2006-Present)

Water ice exposed by impact Avalanche (width was ~180 meters) • http://www.nasa.gov/mission_pages/MRO/multi media/video_archive_1.html Phoenix

• Part of Mars Scout program • First mission run by a university • Landed near Martian North Pole • Dug trenches to search for water • Launched August 4, 2007 • Landed May 25, 2008 • Mission concluded November 10, 2008

http://en.wikipedikipedia.org/wiki/Image:Phoenix_landing.jpg http://en.wikipedia.org/wiki/Image:Phoenix_Lander_seen_from_MRO_during_EDL2.jpg http://en.wikipedia.org/wiki/File:070802_phoenix_lab_02.jpg http://en.wikipedia.org/wiki/Image:Patterned_ground_devon_island.jpg Devon Island

• This polygonal cracking is similar to patterns seen in permafrost areas • A likely formation mechanism is that • ice contracts when the temperature decreases, creating a polygonal pattern of cracks • When the temperature rises and the ice expands back to its former volume, it can’t assume its former shape • It then buckle upwards.

http://en.wikipedia.org/wiki/Image:Phoenix_mission_horizon_stitched_high_definition.jpg http://en.wikipedia.org/wiki/Image:Evaporating_ice_on_Mars_Phoenix_lander_image.jpg pH of Mars

• Latest published value of the pH of Mars is ~7.7 • pH of 7 is neutral • pH <7 is acidic • pH > 7 is basic (alkaline) http://en.wikipedia.org/wiki/File:Phoenix_mini -DVD_on_Mars.jpg Mars Science Laboratory

• Called Curiosity • Will launch in 2011 • Costing ~2.3 billion dollars • It is a rover that will assesssess whether Mars ever was able to support microrganisms • It will be the same size as a Mini Cooper automobile http://en.wikipedia.org/wiki/File:28936main_rover -metric.jpg • http://video.pbs.org/video/1114436021/ Any Questions?