Mars
Essential Points
1. Mars is about half the size of Earth
2. Mars has a thin carbon dioxide atmosphere
3. Mars has volcanoes and faults but no plate
tectonics
4. Mars had liquid water early in its history
5. Evidence for life on Mars is debatable
Mars
• About half the size of Earth
• Rotates in 24.5 hours
• Ranges from 207 to 249 million km (129 to
155 million miles) from Sun
• Period: 687 days
• Two tiny satellites
Mars and Earth
The Surface of Mars
• Thin carbon dioxide atmosphere about 1/150
as dense as Earth’s
• Surface temperatures -20 to -200 C
• Polar caps of ice and frozen carbon dioxide
• Large rift valley (Vallis Marineris)
• Huge Shield Volcanoes (Olympus Mons)
• Evidence for former liquid water
Mars as Lowell Knew It
Lowell’s Mars
Lowell’s Venus
Modern
Imaging
Technology
Improves
Earth-Based
Views of Mars
Greatly
Mars from Mariner 9
Mars Viking Mosaic
Mars Topography
Vallis Marineris
Huge
Landslide in
Vallis
Marineris
Layered Deposits in Vallis Marineris
Active Landslide on Mars
Active Landslide on Mars
Olympus Mons
Summit of Olympus Mons
Phobos over Olympus Mons
Mars’ Polar Caps
Polar Cliffs on Mars
Dunes on Mars
Water on Mars
Channels on
Mars
Floods on
Mars
Where’s the Water Now?
Recent Water on Mars?
How to Lose an Ocean
• If water is exposed to solar UV and
particles, it breaks down to H + O (photodissociation)
• Happens if water gets into upper
atmosphere
– Planet gets hot (Venus)
– Planet loses atmosphere (Mars)
• Oxygen combines with iron and other
elements, on Mars may also have escaped
Landing on Mars
Mars as Seen by Viking
Mars from Pathfinder
Martian Winter
Martian Sunset
Layered
Rocks on
Mars
Cape St. Vincent
Opportunity’s Shadow
Spirit Makes Tracks
Digging Out
Hole on Mars
Wind Erosion on Mars
Ice in Martian Crater
Martian Glacier?
Martian
Glacier?
Martian Dust
Devil
Dust Devil Tracks
Phobos and Deimos
Phobos and its
Shadow
Martian Solar
Eclipses
Earth
From
Mars
Jupiter From Mars
The Face
on Mars
Martian Meteorite
Martian Fossils ?
Essential Points
1. Mars is about half the size of Earth
2. Mars has a thin carbon dioxide atmosphere
3. Mars has volcanoes and faults but no plate
tectonics
4. Mars had liquid water early in its history
5. Evidence for life on Mars is debatable