Approximate Size of Planets

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

Scarps

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

Venus’ Landscape

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

Mars Surface

-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

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)

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

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

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

Planetary Orbits

New Horizons

Intelligent Life

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