Terrestrial Planets

• Mercury• Venus• Earth• Mars

Source of imagesPlanetary photojournal: http://photojournal.jpl.nasa.gov

Mercury ☿

• Mean radius 2439 km = 0.38RE

• Mass 3.3 ˣ 1023 kg = 0.055ME

• Mean density 5427 kg/m3

• Rotation period 58.646 d (length of day)

• Orbital period 88 d (length of year)• → 3:2 spin – orbit resonance• Sun distance ~0.387 AU• http://messenger.jhuapl.edu/

Mercury Volcano

Inner structure

• 1 Crust 100 – 200 km• 2 Mantle -600 km• Nucleus – 1800 km

• Core ~42% of volume• Higher iron content than

any other planet

Mercury surface map

All images: NASA & JHUAPL Messenger Mission

Mercury

Kepler

Debussy

Pantheon Fossae Impact ejecta spokes

Venus

• Mean radius 6051 km = 0.949 RE

• Mass 4868 ˣ 1024 kg = 0.815 ME

• Mean density 5204 kg/m3

• Rotation period -243 d• Orbital period 224.7 d• Sun distance ~0.7 AU• Surface pressure 93 bar

http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html

Venus Magellan Radar Images

Ridges formed by crustal shortening

Eistla region with Gula Mons in the Background

Image resolution Venera vs. Magellan

Earth

• Mean radius 6371 km • Mass 5.973 ˣ 1024 kg• Mean density 5515 kg/m3

• Rotation period -1 d• Orbital period 365.256 d• Sun distance 1 AU • Surface pressure 1 bar

Earth Moon system to scale

Mars

• Mean radius 3396 km = 0.533 RE

• Mass 6418 ˣ 1023 kg = 0.107 ME

• Mean density 3933 kg/m3

• Rotation period 1.026 d = 24.623h• Orbital period 686.98 d• Sun distance ~1.5 AU• Surface pressure 0.7 mbar

http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html Opportunity: Greeley Haven winter stopover

Mars “Homestake” mineral, possibly Gypsum vein from OportunityMRO North polar erg with sand dunes

Snake River Rocks, Curiosity

Mars

MEX: Buried glaciers around Phlegra Montes

Mars

MRO Chemical alteration by water, Jezero Crater Delta