Mars Basics
Size & Distance
 Smaller than Earth (0.532x)
 Mars diam ~ 6779 km (4212
miles)
 Earth diam ~ 12,742 km
(7918 miles)
 8 Mars would fit inside the
Earth!
Size & Distance
Size & Distance
 Smaller than Earth (0.532x)
 Mars diam ~ 6779 km (4212 miles)
 Earth diam ~ 12,742 km (7918
miles)
 8 Mars would fit inside the Earth!
 1.5 AU from the sun (~140 million
miles)
 0.5 AU from the Earth (~43 million
miles)
 SCALE!!!
Scale
 Using a 12-inch Earth globe and 6-inch Mars globe as
a scale:
 Q: How far away do you think Mars would be?
 A: 1.4 km (~0.87 miles)
LPI
McDonald’s
Rotation & Revolution
 One Martian day (sol) is 24
hours and 37 minutes
 One Martian year is 687
Earth days, almost two Earth
years
Seasons
Like Earth, Mars tilts
This tilt contributes to
seasons, orbit also
contributes
Atmosphere
 Yep. Mars has an atmosphere.
 ~95% CO2, ~3% N2, ~2% Ar; traces of
O2, CO
 Surface pressure ~0.006 atm
(~1/100th Earth’s atmosphere)
 Gerard Kuiper made spectroscopic
observations of CO2 in the
atmosphere in 1952; presumed to be
a minor constituent until 1965
Interior
 Core, mantle, crust
 No magnetic field today; data support one in the past
Mars is Cold
 Average temp: -63° C (max & min vary)
 Weirdness above the surface…
Moons
Deimos – 15 km (9.3 miles)
Phobos – 26.8 km (16.7 miles)