Planet Earth

What creates the Earth’s magnetic field

Circulating liquid metal in outer core generates electrical currents

Magentosphere

Formed by the magnetic field; shields Earth from solar wind (stream of

electrically charged particles emitted by Sun).

Magnetic North Pole

Found where the magnetic field enters the plane

Geographic North Pole (true north)

Found at Earth’s axis of rotation

Aurora (aka Northern Lights)

When the sun’s plasmatic wind finds a gap in the planet’s magnetic

field and collides with the atmosphere.

Tropic of Cancer

• The most northerly place on Earth

• Receives direct sunlight during the Northern Hemisphere’s summer

Tropic of Capricorn

• The most southerly location on Earth

• Receiving direct sunlight during the Southern Hemisphere’s summer

James Hutton (1726-1797)

Helped conceptualize uniformitarianism - Earth has always changed in uniform ways; the present is the key to the past

Catastrophism

Earth’s features, like mountains, were formed by catastrophes

Charles Darwin (1809-1882)

Funder of evolutionary biology; looked at uniformitarianism as support for his theory of how new species emerge.

Inner Core (1/6)

• solid iron & nickel

• center to 3,200 mi below

Outer Core (2/6)

• liquid iron & nickel

• 3200 mi to 1800 mi below

Lower Mantle (3/6)

• deforming solid rock

• 1800 mi to 125 mi below

• below the crust

Asthenosphere (4/6)

• softer than the lower mantle

• 64 and 124 mi below

Crust (5/6)

• rigid outermost portion of Earth

• stress from the asthenosphere forms lithospheric plates

Lithosphere (6/6)

• Crust and the lithospheric mantle beneath it

• Moho (Mohorovičić discontinuity):

• Boundary that separates crust from lithospheric mantle

• 62 mi beneath

Magma

Melted rock below the crust’s surface; hardens into granite

Lava

Magma spilled onto the surface of the crust; hardens into basalt

Alfred Wegener (1880-1930)

Proposed the Theory of Coninental Drift (Earth's continents were once joined as a single supercontinent); wrote The Origins of the Continents and Oceans (1915)

Why does magma rise?

It is less dense and more buoyant than lithospheric mantle

Extrusive Igneous Rock (volcanic rock)

Rock that cooled from lava on crust’s surface

Intrusive Igneous Rock (magmatic rock)

Rock that cooled from magma deep underground

Sedimentary Rock

• Sediments are compressed and cemented together (lithified)

• Form only in depositional environments

Endogenic

Internal processes such as volcanic and tectonic activity

Exogenic

External processes such as weathering by wind/water or transporting

Continental Riftng

Places where the continental crust is extending and thinning (often creates bodies of water)

Collision Zones/Convergent Boundaries

Places where two or more tectonic plates have a net movement toward each other

Orogenesis

The process of building mountains and mountain chains at collision zones/convergent boundaries

Subduction

When plates of different density converge