MARS Updated July 14, 2007.

MARS Updated July 14, 2007

2 Mars From the Earth Features from Orbit On the Ground Notes

3 A. Mars from Earth x

Kepler & Mars 4 1605 Using Tycho’s data, Kepler determines the orbit of Mars is an ellipse (9% elliptical) e=0.09 a=1.52 AU P=1.88 year

5 Earth-based observations of Mars are best made during favorable oppositions The best Earth-based views of Mars are obtained when Mars is simultaneously at opposition and near perihelion

Observations of Mars 1659 Christopher Huygens 6
Estimates size of Mars to be 60% of earth identifies feature on Mars (Syrtis Major), estimates rotation rate of 24 hours 1672 saw “white spot” at south pole (i.e. the ice cap)

Observations of Mars 7 1666 Gian Cassini measures rotation period 24h37m 1781 Herschel measures Mars is tilted 24, hence it has “seasons” 1704 Miraldi sees ice cap not centered on south pole, and in 1719 sees north ice cap. 1813 Flaugegues sees ice caps change (i.e. “melt” during summer) and earlier in 1809 saw yellow clouds (dust storms)

Earth-based Observations
8 Earth-based Observations A solar day on Mars is nearly the same length as on Earth Mars has polar caps that expand and shrink with the seasons The Martian surface undergoes seasonal color changes

10 Starting in the 1870s, Giovanni Schiaparelli (Italy) began observing Mars with a small telescope. He sketched long, narrow lines that he called “canali”. This was translated into English as “canals”, and the myth of the canals on Mars was born.

A few observers reported a network of linear features called canals
11 Earth-based observations were once thought to show evidence of intelligent life on Mars A few observers reported a network of linear features called canals These observations, which proved to be illusions, led to many speculations about Martian life

Wealthy Bostonian Percival Lowell became fascinated
12 Wealthy Bostonian Percival Lowell became fascinated with the canals of Mars, and built his own observatory to observe them himself. His books and magazine articles in the early 1900s captured the public imagination about a dying civilization on Mars. Voyagers In Astronomy Percival Lowell in about 1910, observing with his 24-inch telescope at Flagstaff, Arizona. (Lowell Observatory) Percival Lowell at his telescope at the Lowell Observatory, Flagstaff, Arizona. Early 1900s p.197

13 Lowell’s global map of Mars, showing the canals that he saw.
Lowell believed that Mars had a dying civilization, desperate for water and food. The canals were thought to carry water from the polar caps to the desert regions for agriculture. Figure 9.3 Lowell’s Mars Globe One of the remarkable globes of Mars prepared by Percival Lowell, showing a network of dozens of canals, oases, and triangular water reservoirs that he claimed were visible on the red planet. (Lowell Observatory) Fig 9-3, p.198

saw the surface markings, but no canals of the kind
14 Other astronomers observed Mars with large telescopes and saw the surface markings, but no canals of the kind Schiaparelli and Lowell had reported. For decades, some astronomers debated the reality of the canals, while most astronomers ignored the issue entirely. The canals could not be reliably photographed with the telescopes of the time. Drawing by E. M. Antoniadi, 1909

15 This is what Mars looks like to a trained observer using a moderate
size telescope. Figure 9.2 Mars Seen from the Earth’s Surface These are among the best Earth-based photos of Mars, taken in 1988 when the planet was exceptionally close to the Earth. The polar caps and dark surface markings are evident, but not the topographic features. (Steve Larson, University of Arizona) Fig 9-2, p.196

16 This is what Mars looks like with the Hubble, showing ice cap and clouds And with a dust storm Figure 9.2 Mars Seen from the Earth’s Surface These are among the best Earth-based photos of Mars, taken in 1988 when the planet was exceptionally close to the Earth. The polar caps and dark surface markings are evident, but not the topographic features. (Steve Larson, University of Arizona)

17 here’s what we were learning about Mars with our bigger and better telescopes: It has reddish colored regions and gray-green colored regions on its surface It has an atmosphere of CO2 White clouds come and go Yellow dust clouds occasionally cover the whole planet for several weeks at a time It rotates on its axis in about one Earth day It has seasons It has polar caps made of CO2 ice (“dry ice”)

Getting to Mars is HARD! ~33% Success Rate 18 Mars 6 USSR 8/5/73
[Unnamed] USSR 10/10/60 [Unnamed] USSR 10/14/60 [Unnamed] USSR 10/24/62 Mars 1 USSR 11/1/62 [Unnamed] USSR 11/4/62 Mariner 3 U.S. 11/5/64 Mariner 4 U.S. 11/28/64 Zond 2 USSR 11/30/64 Mariner 6 U.S. 2/24/69 Mariner 7 U.S. 3/27/69 Mariner 8 U.S. 5/8/71 Kosmos 419 USSR 5/10/71 Mars 2 USSR 5/19/71 Mars 3 USSR 5/28/71 Mariner 9 U.S. 5/30/71 Mars 4 USSR 7/21/73 Mars 5 USSR 7/25/73 Mars 6 USSR 8/5/73 Mars 7 USSR 8/9/73 Viking 1 U.S. 8/20/75 Viking 2 U.S. 9/9/75 Phobos 1 USSR 7/7/88 Phobos 2 USSR 7/12/88 Mars Observer U.S. 9/25/92 Mars Global Surveyor U.S. 11/7/96 Mars 96 Russia 11/16/96 Mars Pathfinder U.S. 12/4/96 Nozomi (Planet-B) Japan 7/4/98 Mars Climate Orbiter U.S. 12/11/98 Mars Polar Lander/Deep Space 2 U.S. 1/3/99 Mars Odyssey U.S. 4/7/01 Mars Express ESA 6/2/03 Mars Exploration Rovers U.S. Summer 03 Mars Reconnaissance Orbiter U.S /12/05 ~33% Success Rate

First Spacecraft Image of Mars
19 First Spacecraft Image of Mars Mariner 4 (July 1965) Area = 330 km x 1200 km Resolution ~5 km

Mariner 4 (July 1965) visits Mars
20 Mariner 4 (July 1965) visits Mars Area = 330 km x 1200 km Resolution ~5 km Shows craters!

What did we learn from Mariner 4?
21 What did we learn from Mariner 4? • Mars = Moon-like, cratered terrain • Surface pressure = 4-7 mbar • Daytime temperature ~ -100ºC • No appreciable magnetic field Mars is DEAD, geologically and biologically. 262 km x 310 km First image of Mars showing unambiguous evidence of craters

Mars is still DEAD, geologically and biologically.
22 Mariners 6 & 7 • More images of cratered Mars • Happened to miss the large volcanoes and canyon system (to be discovered later!) • South polar cap = CO2 • Showed that dark features once thought to be “canals” were not evidence of a martian civilization Mars is still DEAD, geologically and biologically. 900 x 692 km Schiaparelli’s Mars map (1888)

Mariner 9, 1971 23 • First spacecraft to orbit another planet
Phobos (20 x 28 km) • First spacecraft to orbit another planet • Planet-wide dust storm upon arrival (argues for orbiting missions, not just fly-bys) • Returned 7,329 images • Tremendous scientific return Deimos (10 x 16 km)

24 Olympus Mons

Mariner 9: Volcanoes 25 OLYMPUS MONS
• Central caldera ~80 km in diameter • 27 km in height (3x Mount Everest) • Lava flows radiate 500 miles away from volcano Olympus Mons, 27 km high Mt. Everest, 9 km high Mauna Kea, 10 km high UND Mariner 9 image

Mariner 9: North Polar Cap
26 Mariner 9: North Polar Cap • Cap ~1000 km in diameter - but shrinks seasonally! Mariner 9 image

Mariner 9: Aeolian Activity
27 Mariner 9: Aeolian Activity • Irregular pits and depressions near south pole • Flat floors and smooth walls • Similar to terrestrial deflation hollows Mariner 9 image, 75 x 75 km Mariner 9 image

Mariner 9: Vallis Marineris
28 Mariner 9: Vallis Marineris •“Labyrinth” at western end of Vallis Marineris • Linear graben, grooves, and crater chains dominate Mariner 9 image, 400 x 400 km

Vallis Nirgal, 575 km long and 5-6 km wide.
29 Mariner 9: River Beds Mariner 9 image Vallis Nirgal, 575 km long and 5-6 km wide.

Mariner 9: Partially Closed Valleys
30 Mariner 9: Partially Closed Valleys • Not associated with any familiar terrestrial processes • Mars crust appears to have either collapsed along a network of fractures or erosional processes preferentially removed material along fractures.

31 Mariner Missions • Mars used to be a very dynamic planet (volcanoes, water activity, etc). • Mars is still somewhat active (polar caps, dust storms), but likely not as active as it was in the past (ancient terrain indicated by abundance of impact craters).

32 Viking Viking 1: launch 20 Aug 1975 Viking 2: launch 9 Sept 1975

First image ever transmitted from the surface of Mars!
33 Viking 1 First image ever transmitted from the surface of Mars! [July 20, 1976]

34 Viking 2: Surface Frost

Viking 1: Landing Site 35 Large rock ~ 2 meters wide
Top of rock covered with red soil Exposed rock similar in color to basaltic rocks on Earth This rock = fragment of lava flow that was later ejected by impact crater? Red surface color due to oxidized iron in the eroded material Characterized by rocky plains and also small drifts of regolith

36 Viking 2: Landing Site More and larger blocks of stone than Viking 1 site Stones are likely ejecta from nearby impact craters Many rocks are angular, only slightly altered by wind erosion Drifts of sand and dust are small and less noticeable than Viking 1 site Pink sky color caused by extremely fine red dust suspended in thin atmosphere

Mars Global Surveyor 37 NASA spacecraft Launched 7 Nov 1996
Instruments Mars Orbiter Camera (MOC) Mars Orbiter Laser Altimeter (MOLA) Thermal Emission Spectrometer (TES)

Mars Global Surveyor: MOC
38 Mars Global Surveyor: MOC New Boulder Tracks

39 Mars Global Surveyor: MOC Channels 1 km 1 km 1 km Apsus Valles channels Streamlined island Channel in Kasei Valles

40 Mars Global Surveyor: MOC Clouds Clouds over Tharsis volcanic region

41 Mars Global Surveyor: MOC Lava Flows 1 km Lava flow front and trough in Daedalia Planum (southern Tharsis) Rugged lava flows on the flanks of Olympus Mons 1 km Lava flow south of Tharsis

42 Mars Global Surveyor: MOC Gullies 1 km 1 km 1 km Evidence for recent water on Mars?

43 Mars Global Surveyor: MOC Slope Streaks 1 km 1 km

44 Mars Global Surveyor: MOC Frost 100 km

Mars Global Surveyor: MOLA
45 Mars Global Surveyor: MOLA Mars Orbiter Laser Altimeter MOLA Science Team

The origin of this crustal dichotomy is not completely understood
The heavily cratered southern highlands are older and about 5 km higher in elevation than the smooth northern lowlands The origin of this crustal dichotomy is not completely understood 46

Mars Global Surveyor: MOLA
47 Mars Global Surveyor: MOLA Ancient Shorelines? Head et al., Science 286, 1999.

48 Figure 9.13 Mars Globe from Radar These globes are highly precise topographic maps, reconstructed from millions of individual elevation measurements with the Mars Global Surveyor spacecraft. Color is used to indicate elevation. The hemisphere on the left includes Olympus Mons, the highest mountain on Mars, while the hemisphere on the right includes the Hellas basin, which has the lowest elevation on Mars. (JPL/NASA)

Lightly cratered northern hemisphere
49 Lightly cratered northern hemisphere Ancient, heavily cratered Southern hemisphere Figure 9.13 Mars Globe from Radar These globes are highly precise topographic maps, reconstructed from millions of individual elevation measurements with the Mars Global Surveyor spacecraft. Color is used to indicate elevation. The hemisphere on the left includes Olympus Mons, the highest mountain on Mars, while the hemisphere on the right includes the Hellas basin, which has the lowest elevation on Mars. (JPL/NASA) Fig 9-13, p.206

Four Giant Martian Volcanoes
50 Four Giant Martian Volcanoes Olympus Mons: the largest volcano in the Solar System Tharsis Volcanic Ridge Arsia Mons

51 Figure Olympus Mons The largest volcano on Mars, and probably the largest in the solar system, is Olympus Mons, illustrated in this computer generated rendering based on data from the Mars Orbiter Laser Altimeter. Placed on Earth, the base of the Olympus Mons would completely cover the state of Missouri; the caldera, the circular opening at the top, is 65 km across, about the size of Los Angeles. Note the extensive clouds over the lower slopes of the volcano. (Computer graphic by artist Kees Veenenbos) Olympus Mons Fig 9-14, p.206

Olympus Mons on Mars is the largest and the
53 Olympus Mons on Mars is the largest and the tallest volcano in the Solar System. Figure The Highest Mountains on Mars, Venus, and Earth Mountains can rise taller on Mars because the surface gravity is less and there are no moving plates. The vertical scale is exaggerated by a factor of 3 to make comparison easier. Why can a volcano grow taller on Mars than on the Earth or Venus ? Fig 13-14, p.304

A close-up of the caldera in Olympus Mons
54

Even closer up – a landslide on a volcanic slope
55

Erosion A very important process on Mars
56 Erosion A very important process on Mars Ancient erosion shows evidence for flowing water in the early history of Mars These drainage channels were caused by flowing water. Liquid water cannot exist on Mars now because the atmospheric pressure is so low.

57 Figure 9.24 Outflow Channels Here we see a region of large outflow channels, photographed by Viking. These features appear to have been formed in the distant past from massive floods of water. The width of this image is about 150 km. (NASA/JPL) Fig 9-24, p.213

58 Landslides Figure 9.15 Martian Landslides This Viking orbiter image shows one section of the Valles Marineris canyon system. The canyon walls are about 100 km apart here. Look carefully and you can see enormous landslides whose debris is piled up underneath the cliff walls, which tower some 10 km above the canyon floor. (NASA/USGS) Fig 9-15, p.207

Why is Mars red ? Just as in the deserts on Earth, iron in the rocks
59 Just as in the deserts on Earth, iron in the rocks is oxidized, forming iron oxide (rust), with its red-orange color. Rocks and soil in the Arizona desert

Mars Express 60 ESA (European Space Agency) spacecraft
Launched 2 June 2003 Instruments • High Resolution Stereo Camera (HRSC) • Visible and Infrared Mineralogical Mapping Spectrometer (OMEGA) • Subsurface Sounding Radar Altimeter (MARSIS) • Planetary Fourier Spectrometer (PFS)

Mars Express: HRSC 61 “Frozen Sea” on Mars?
Evidence of “pack ice” near martian equator in Elysium Planitia. Dust covers the ash which protects the ice from sublimation. This region is relatively young as evidenced by the lack of impact craters. ESA: HRSC

Mars Express: HRSC 62 MARS EARTH ESA: HRSC
Murray et al., LPSC abstract #1741, 2005.

63 Mars Express: HRSC Melas, Candor, and Ophir Chasmas: Center of Valles Marineris 100 km ESA: HRSC

Mars Express: HRSC 64 Fractured crater near Valles Marineris.
Formation: Cooled lava, dried clay, frozen ground? 10 km ESA: HRSC

Water ice in crater near martian north pole.
Mars Express: HRSC Water ice in crater near martian north pole. 10 km ESA: HRSC

Mars Express: HRSC Nicholson Crater central peak, subsequently reworked by underground processes, atmospheric deposition, fluvial erosion? ~25 km ESA: HRSC

“Hourglass” crater filled with traces of glacier.
67 Mars Express: HRSC “Hourglass” crater filled with traces of glacier. ESA: HRSC ESA: HRSC

68 Mars Express: OMEGA South polar cap, pink areas indicate carbon dioxide ice, green & blue areas indicate water ice. ESA: OMEGA

Mars Odyssey 69 NASA spacecraft Launched 7 April 2001 Instruments
• Gamma Ray Spectrometer (GRS) • Thermal Emission Imaging System (THEMIS)

Mars Odyssey: GRS 70

Mars Odyssey: THEMIS 71 Sand Dunes Proctor Crater North Polar Erg 5 km
NASA/JPL/ASU NASA/JPL/ASU

Mars Exploration Rovers Opportunity: Launched 7 July 2003
72 Mars Exploration Rovers Instruments • PanCam (landscapes, structure, textures) • Mini-TES (identify rocks and soils, atmosphere temperature profiles) • Mossbauer Spectrometer (iron-bearing mineralogy) • APXS (Alpha Particle X-Ray Spectrometer, elemental abundances) • Microscopic Imager (close-up images of rock and soil) • Rock Abrasion Tool (to expose fresh, unweathered rock surfaces) • Magnets (to determine if dust particles are magnetic) JPL/NASA/Caltech Opportunity: Launched 7 July 2003 Spirit: Launched 10 June 2003

Mars Exploration Rovers: Landing Sites
73 Mars Exploration Rovers: Landing Sites

Mars Exploration Rovers: Opportunity
74 Mars Exploration Rovers: Opportunity Eagle Crater Panorama JPL/NASA/Caltech “Hematite map” from mini-TES superposed on PanCam image. Red = more hematite, blue/green = less hematite. JPL/NASA/Caltech

75 Mars Exploration Rovers: Opportunity Evidence of water 1. Blueberries on Mars Spherules (likely composed of hematite) are probably concretions created in water. Spherules are found randomly and evenly spread throughout rock matrix (e.g. not layered). JPL/NASA/Caltech JPL/NASA/Caltech

76 Mars Exploration Rovers: Opportunity JPL/NASA/Caltech Burns Cliff inside Endurance Crater

Mars Exploration Rovers: Spirit
77 Mars Exploration Rovers: Spirit First grinding of a rock on Mars - Adirondack Rock. RAT: mm in diameter, 2.65 mm deep. JPL/NASA/Caltech

78 Mars Exploration Rovers: Spirit Humphrey: Small amounts of water? Humphrey is a volcanic rock (formed by cooling magma). However, bright material in interior crevices and cracks may be minerals crystallized out of water. A volcanic rock with a little fluid moving through it. JPL/NASA/Caltech Humphrey is 60 cm (~2 feet) tall. Note RAT mark on rock.

79 Mars Exploration Rovers: Spirit Bonneville Crater JPL/NASA/Caltech

Mars Exploration Rovers: Spirit More bright soil (March 23, 2006)
80 Mars Exploration Rovers: Spirit More bright soil (March 23, 2006) Salty chemistry with iron-bearing sulfates? Indicative of past water since salts are easily mobilized and concentrated in liquid solution? Common along flanks and floors of Columbia Hills? JPL/NASA/Caltech

81 Mars Exploration Rovers: Spirit

Summary of terrestrial planet evolution
82 Least Geologically Evolved Figure Stages in the Geological History of a Terrestrial Planet In this graph, time increases downward along the left axis and the stages are labeled. Each planet is shown roughly in its present stage. The smaller the planet, the more quickly it passes through these stages. Most Geologically Evolved Fig 13-13, p.303

83 Earth and Mars began with similar atmospheres that evolved very differently Mars’s primordial atmosphere may have been thicker and warmer than the present-day atmosphere It is unclear whether it contained enough carbon dioxide and water vapor to support a greenhouse effect that would permit liquid water to exist on the planet’s surface The present Martian atmosphere is composed mostly of carbon dioxide The atmospheric pressure on the surface is less than 1% that of the Earth and shows seasonal variations as carbon dioxide freezes onto and evaporates from the poles

Clouds Above Mars’ Mountains
84 Clouds Above Mars’ Mountains

Earth’s Atmosphere 85

Mars Atmosphere 86

The Martian atmosphere changes dramatically with the seasons
87 The Martian atmosphere changes dramatically with the seasons Great dust storms sometimes blanket Mars Fine-grained dust in its atmosphere gives the Martian sky a pinkish-orange tint Seasonal winds blow dust across the face of Mars, covering and uncovering the underlying surface material and causing seasonal color changes

Afternoon dust devils help to transport dust from place to place
89 Afternoon dust devils help to transport dust from place to place

90 Winter Frost

The two Martian moons resemble asteroids
91 The two Martian moons resemble asteroids Mars has two small, football-shaped satellites that move in orbits close to the surface of the planet They may be captured asteroids or may have formed in orbit around Mars out of solar system debris

92 References

MARS Updated July 14, 2007.

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