Terrestrial Worlds 3

Mars

Mars basics• 4th planet from Sun (1.5 AU), 7th largest world• Orbit - 1.88 Earth years• Sidereal rotation - 25 hours• Surface gravity- 3.71 m/s2 (39% of Earth)• 0.007 bars of pressure (1/100 x Earth)

• 96% CO2 3.5% N2 < 1% others • Temperatures- 13 oF in day (max. recorded 63 oF) - -135 oF at night (min. -200 oF at poles)• Too cold for liquid water (only ice or gas)• Spacecraft- Most visited world (USA,Russia,Europe,India)

Map of Mars

Color height map of Mars(Red-high, Blue-low)

Mars Polar Caps -Solid CO2

North South

Mars- Volcanism• Two main types of Volcanism:

• Older- fluid lavas, flood plains and flattish volcanoes (forms the older surfaces on Mars)

• Younger- large shield volcanoes (Tharsis region and Elysium region).

– Note. The volcanoes pour out as much lava as the Hawaiian islands, but without plate tectonics it piles

up in 1 place, making giant volcanoes.

Tharsis Bulge Volcanic region

Olympus Mons

Largest Volcano in the Solar System

Mars tectonics -Tharsis extension faulting

Tharsis extension faultingNoctis Labyrinthusand Valles Marineris

Tectonic cracking 3000 miles long

Valles Marineris

Valles Marineris -3D View 7 miles deep, widening by surface processes

Mars Cratering

• Surfaces old in southern highlands

• ‘Middle aged’ in the Northern lowlands

• Largest craters are in south, from age of Heavy Bombardment:– Argyre basin ~1120 miles across– Hellas ~1430 miles across

Mars Cratering - Hellas basin

Mars Cratering

- Hellas is over 9km deep

Mars Surface Processes -

Wind

Fields of sand dunes

Mars Surface Processes - WaterWater channels seen across the surface

Mars Surface Processes - Water

Water channels seen across the surface

Landing sites

Gusev Crater &Ma’adim Vallis

Spirit’s landing site

Opportunity at Sinus Meridiani - A dried up lake?

• Sedimentary strata and rock chemistry provide evidence of former running water on Mars.

High sulfur & chlorine levels- salt pan from dried lake.“Blueberries” -spheres of hematite made in water.

Curiosity at Gale Crater

Surround view within Gale Crater

• Fine mudstones above cemented sandstones

The Missing Water -Underground Ice?Impacts into ice-rich surfaces, could produce muddy craters

Changing Gullies –In Real Time

Dark streaks are from salty water seasonally leaking out of the crater wall

The Martian Atmosphere

• 0.007 bars of pressure (1/100 x Earth)

• 96% CO2 3.5% N2 < 1% others • Temperatures- 13 oF in day (max. recorded 63 oF)-135 oF at night (min. -200 oF at poles)

• Current pressure/temperature conditions are too low for stable liquid water. Water found as gas or ice.

The Martian Atmosphere Amosphere is controlled

by the polar ice

• Winter -CO2 freezes on pole.

• Summer -CO2 boils off pole.

Gas moves across Mars from the winter to summer pole and back

& Blue Sunsets

Pink Skies

• Mars has not had widespread surface water for 3 billion years

• Greenhouse effect probably kept surface warmer before that

• Somehow Mars lost most of its atmosphere

Climate Change on Mars

• Traces of magnetic field only found on oldest rocks.• Younger rocks no field.• Mars once had magnetic field early on, but not today.

• Magnetic field may have preserved early Martian atmosphere.

• Solar wind may have stripped atmosphere away after field decreased because of interior cooling.

• If much water and carbon dioxide was lost, the Martian greenhouse effect would decrease and the temperatures would be too low for liquid water.

© 2014 Pearson Education, Inc.

Which of the following is not a similarity between Mars and

Earth today?

A.The lengths of their days are similar.

B.They both have polar ice caps.

C.They both have flowing rivers.

D.They both have shield volcanoes

© 2014 Pearson Education, Inc.

Should we land on Mars and search for life?

A. Yes, if we found evidence of life it would have important scientific implications.

B. Yes, if we found evidence of life it would have major scientific, philosophical, and religious implications.

C.No, it's too expensive.

D.No, at best we're likely to find fossils, and they aren't interesting.

Summary of TerrestrialsContain the processes in differing amounts, resulting in wildly different surfaces

Impact Cratering Volcanism Tectonics

Surface Processes