1. Approximate Size of Planets

7. Mercury no atmosphere/what little exists = O2 & Na
in 2 of Mercury’s years, 3 days pass
daytime temp = 427 degrees C, night = -173 degrees C
believed to have iron-nickel core
surface is similar to moons
covered with craters, plains, & scarps
would have more if not for volcanic activity

8. Scarps

9. Venus
has no moons
has thick clouds – radar was used before explorations
very hot – thick atmosphere
1 Venus day = 243 Earth days
retrograde rotation – rotates opposite of Earth
average surface temp = 464 degrees C
atmosphere mainly contains CO2 & N
clouds are made of sulfuric acid
surface is smooth because of volcanic activity

10. Venus’ Landscape

11. Mars thin atmosphere, but turbulent
southern hemisphere heavily cratered
northern hemisphere is dominated by plains
has polar ice caps – mainly composed of frozen CO2
believed core of iron-nickel
2 moons – Phobos & Deimos

14. Mars Surface

18. -diameter is 10 times larger then Earth
-mass makes up 70% of matter in solar system
-atmosphere mainly composed of H & He
-fastest rotation of all the planets
-contains alternating cloud types (belts & zones)
-has rings

21. Saturn 2nd largest planet would float in water
atmosphere dominated by H & He
rings are composed of rocks and ice that range in size
7 major rings
many named satellites (Titan is major one)

22. Uranus has many moons and 10 rings discovered accidentally in 1781
atmosphere mainly H and He, but contains a little methane
very few clouds
average temp = -215 degrees C
is tilted on its side

23. Neptune existence was predicted before it was discovered
has persistent Great Dark Spot, which disappeared in 1994 – a new storm has formed
many moons – Triton has a thin atmosphere and nitrogen geysers
has 6 rings

24. Dwarf Planet Pluto (Plutoid)
discovered in 1930
3 moons named Charon, Hydra, and Nix
known as a dwarf planet (5 current ones right now)
solid surface of rock and ice
has atmosphere of methane and nitrogen (at times)
some scientists questioned if Pluto was even a planet before 2006 because of the following:
has an irregular orbit
very small
could be part of Kuiper Belt

25. Planetary Orbits

26. New Horizons

28. Intelligent Life

29. Mars
Europa – icy surface, but could contain watery slush underneath
Titan – evidence of methane lakes
Io – volcanic activity might sustain life, but there is absence of water