Chapter 28

Mars

The god of WAR

Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Mars• Mars is the most explored planet

– Viking 1 & 2

– Mariner 4 provided the first close-up image (1965)

– ESA’s Mars Express (2003)

– Global Surveyor

– Odyssey

(aside from Earth) in the Solar System

Mars• Mars is the most explored planet (aside from Earth) in the Solar System

Viking Spacecraft and the view of Mars

https://www.youtube.com/watch?v=PseSJoicfrg

Viking 1 Spacecraft view

Viking 2 Spacecraft view

• Mars is the most explored planet (aside from Earth) in the Solar System

– Pathfinder in 1997 landed on the planet w/Sojourner

– Pathfinder’s view

• Mars is the most explored planet (aside from Earth) in the Solar System– Summer 2003

Opportunity

• Opportunity’s view

• Mars is the most explored planet (aside from Earth) in the Solar System

– Spirit rovers 1st landed in2004

• Mars is the most explored planet– Spirit panaromic view of mars– A lot of things exploring Mars…

LIKE…

– UFO sighting

• Mars is the most explored planet

– Even Bigfoot is exploring Mars!!!

• Mars is the most explored planet– WHAT is it???

• Mars is the most explored planet

– Face on Mars

Maybe it’s Megatron???

The REAL face of Mars

The REAL face of Mars

• Mars is the most explored planet (aside from Earth) in the Solar System– Phoenix in 2007 to look at one

of the poles

– View from Phoenix

• Mars is the most explored planet (aside from Earth) in the Solar System– Mars Global

Surveyor • flow of liquid

• Mars is the most explored planet– Mars Global Surveyor MAP

• Also studied flow of liquid

• Odyssey Spacecraft

• Odyssey

Globally mapped the amount and distribution of many chemical elements and minerals that make up the Martian surface.Maps of hydrogen distribution led scientists to discover vast amounts of water ice in the polar regions buried just beneath the surface.

Odyssey also recorded the radiation environment in low Mars orbit to determine the radiation-related risk to any future human explorers who may one day go to Mars.

• Most recent spacecraft was in 2012

• Curiosity landed

Click on above link to watch the landing.Click on the

link (below) to see full

Landing

• Curiosity is the first spacecraft to record a landing on another planet. The six-wheel rover arrived on Aug. 5, 2012 to begin a two-year mission to examine whether the Martian environment was hospitable for microbial life.

• The rover's ultimate destination is Mount Sharp, a towering mountain that looms from the ancient crater floor. Signs of past water have been spotted at the base, providing a starting point to hunt for the chemical building blocks of life.

• Before Curiosity journeys toward the mountain, it will take a detour to an intriguing spot 1,300 feet away where it will drill into bedrock. With the test drive out of the way, Curiosity was expected to stay at its new position for several days before making its first big drive -- a trip that will take as long as a month and a half.

• Curiosity won't head to Mount Sharp until the end of the year.

The Surface of Mars

• The surface of Mars is currently a dry, dusty place

• Plains covered with rocks ranging from pebble-sized to boulder sized!

• Lots of evidence for flowing water, rivers and salty oceans

The Surface of Mars• The surface

of Mars is reddish in color.

• This orange sand is mostly rust… (Fe2O3) due to the iron oxide within the soil

Major Features of Mars

• Mars is home to some amazing sites!– Valles Marineris

Major Features of Mars

– Valles Marineris• Named for Mariner 4• A canyon that stretches across the face of the globe• As wide as the United States!

Major Features of Mars

• Mars is home to some amazing sites!– Like:Olympus Mons

Olympus Mons• Tallest mountain of the major planets

Olympus Mons

• Extends above the bulk of the atmosphere of Mars!

• An extinct shield volcano around 250 million years old.

Map of Mars

• Four gigantic shield volcanoes are located near the equator, near a region called the Tharsis Plateau

Map of Mars

• The Tharsis bulge may have been caused by an upwelling of hot material from the interior of the planet. This created volcanoes in the region (including Olympus Mons) and may have created Valles Marineris.

Map of Mars

• The Tharsis bulge may have been caused by an upwelling of hot material from the interior of the planet. This created volcanoes in the region (including Olympus Mons) and may have created Valles Marineris.

Major Features of Mars

• Mars is home to some amazing sites!– Polar ice caps

Major Features of Mars

The polar caps of Mars are composed mostly of water ice (north) and frozen carbon dioxide (south)

Ice Caps of Mars

• They grow and shrink seasonally– Similar axial tilt to

Earth (25 degrees)– Produces seasons

similar to those on Earth

– Southern winter is much more extreme than northern, as Mars is farthest from the sun during this period.

Major Features of Mars

The northern hemisphere has sparsely cratered plains.

The southern hemisphere of Mars is a heavily cratered, highland region resembling the highlands of the Moon.

Dune Fields• Deserts ring Mars at mid-

latitudes• Winds blow surface material

into dunes, similar to those found on Earth

Water on Mars?

• Many scientists believe that Mars was once warmer and wetter than it is today

• Surface features seem to support this– Dry riverbeds– Splash craters– Gullies in crater walls– Etc!

Evidence for Water

Splash Craters are craters that form from impacts on damp soil

Gullies

Ice Floes?

Where the water is now

• If Mars was so wet, where did all the water go?

Where the water is now

– Some may be trapped just below the surface as permafrost

– May be locked up in mineral compounds

Where the water is now

– Most probably escaped to space• Evaporated from the surface

• UV photons broke apart H2O molecule

• H escaped to space

• The Martian atmosphere is very different from Earth’s– 95% carbon

dioxide, – 3% nitrogen– Surface pressure is

very low – same pressure as Earth at 35 km!

The Martian Atmosphere

The Martian Atmosphere

Clouds of water ice and carbon dioxide ice float through the sky

No rain ever falls, but it sometimes snows dry ice crystals!

In order for a planet to retain an atmosphere the 2 most important are:

Temperature of planetEscape velocityDistance from the SunAxial tiltComposition & weight of the gases.

• Temperatures range from just above freezing to 180 K (-136ᵒF)

The Martian Atmosphere

• The winds on Mars, though gentle, can carry dust far into the atmosphere.– These dust storms sometimes obscure most of the surface!

• No erosion

The Martian Atmosphere https://www.youtube.com/watch?v=PseSJoicfrg

• The winds on Mars

Interior of Mars Astronomers hypothesize that Mars has a core of iron, nickel, and possibly sulfur that extends somewhere between 1200 km and 2400 km from the center of the planet. Because Mars has no magnetic field, astronomers think that the core is probably solid.

Moons of Mars

• Mars has two moons, Phobos and Deimos.

Phobos• It’s about 15.5 miles diameter (about the size of

Houston, TX)

• Its gravity is 1/1000 of earth– You could jump off the surface (about a mile up)

and float off into space– Could lift a 900,000 pound object

Phobos• You could summersault over 3000 times BEFORE you

land 25 minutes later • Covered with a Dark dust about 3 feet deep

– Dark as charcoal

• TEMP: +30ºF to a -170ºF night• Rotation is about 8 hours

Phobos• crater (“stick me”) on the west side

– It’s a 7 mile wide which almost split the moon in half – A 200 mile wide meteor traveling at 14000 MPH hit

the West side of the moon– Larger than the United States – Could go Spelunking on Mars

Moons of Mars• DeimosMoon (dia): 7.8miles

Orbit eccentricity: 0.0002

Orbit inclination: 1.788 degrees

Rev: 30 hours

Rot: none

Mass: 1.4762 x 10^15 kg

Density: 1.471 g/cm^3

Surface gravity: 0.003 m/s^2

Escape velocity: 13 mph (20 km/h)

Chapter 28

Mars

The god of WAR

Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.