High P and T at center of Solar nebula cause hydrogen atoms to fuse together to form helium

Solid particles condense and collide to form planetesimals which accrete into planets

Lindsley, 8/99

Solar system: outer jovian planets, inner terrestrial planets,

Pluto the oddball

Lindsley, 8/99

Jovian planets:• Low densities

• Overall mass is large

• Thick atmospheres over small rocky cores

Lindsley, 8/99

Terrestrial planets:

• Relatively small

• Relatively high densities

• Mostly rock with only a thin, or no, atmosphere

Lindsley, 8/99

Basalt forms most of the surface area of terrestrial planets

Lindsley, 8/99

Manicouagan Crater (Quebec) is evidence of meteorite impact.

210 m.y. old

75-100 km across

Filled with

a ring lake

Lindsley, 8/99

Earth is unusual because it is rich in water and its crust (outermost layer)

includes other rocks than basalt

Lindsley, 8/99

Active plate tectonics causes earthquakes and volcanic eruptions, but also recycles oxygen and other biochemical necessities

Lindsley, 8/99

Sand dunes, Namibia

Lindsley, 8/99

Wind-deposited sandstone,

Zion National Park, Utah

Lindsley, 8/99