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Chapter 7

Geologically active- continually being restructured. Interior structure

Core- the highest density material consisting primarily of metals such

as nickel and iron resides in the central core Mantle- Rocky material of moderate density mostly minerals that

contain silicon oxygen and other elements forms the thick mantlethat surrounds the core.

Crust the lowest density rock such as granite and basalt forms thethin crust essentially representing the worlds outer skin

lithosphere- earths outer layer consisting of relatively cool rigid rockresting on warmer softer rock beneath.

Differentiation- gravity separating different levels of earths makeup Surface area : volume ratio means that if the earth and moon started out

the same size, the moon has 4 times the surface area ratio and it wouldcool 4 times as fast as long as no additional heat was added

The process by which hot material rises and expands while cooler materialcontracts and calls is called convection.

Interior heat is also responsible for earths global magnetic field. Earth's magnetic field is more similar to that of an electromagnetic field in

which the magnetic field arises as a battery forces charged particles tomove along a coiled wire.

Earths magnetic field helps protect the surface from energeticle partoc;esthat continually flow outward from the sun with solar wind. Theseparticles could strip away atmospheric gas and cause genetic damage toliving organisms.

Magnetosphere- the magnetic field shields us by creating this. A kind ofprotective bubble that surrounds our planet.

Aurora- the few particles that make it through tend to be channeled to thepoles where they collide with atoms and molecules in our atmosphereand create beautiful light.

Impact cratering- the excavation of bowl shaped impact craters byasteroids or comets crashing into a planets surface.

Volcanism- the eruption of molten rock or lava from a planets interior ontoits surface.

Tectonics- the disruption of a planets surface by internal stresses Erosion- the wearing down or building up of geological features by wind

water ice and other phenomena of planetary weather. Outgassing- volcanic eruptions later released some of this gas into the

atmosphere Tectonics is particularly important on earth because the underlying

mantle convection fractured eaths lithosphere into more than a dozenplates

These plates mover over under and around each other leading to a specialtype of tectonics that we call plate tectonics

Over long periods of time erosion has piled sediments into layers on thefloors of the oceans and seas forming sedimentary rock

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X ray photons smack into molecules and ionize and can damage livingtissue.

We owe our protection from the sun to a rare gas called ozone Greenhouse effect- our atmosphere traps additional heat Greenhouse gasses- gases that are particularly good at absorbing infrared

light Lunar maria- smoother and darker regeions of the moon Micrometeorites- micro sand particles that occur frpom other planets and

asteroids in the solar system. Caloris basin- huge impact crater on mercury and spans more than half of

mercury's radius and its multiple rings bear witness to the violent impactthat created it.

Mercury also has huge 3 kilometer cliffs all over its surface Mars clearly used to have water, but not anymore Olympus Mons- largest volcanic thing ever and stands on mars and

proved that it used to flow Spirit and opportunity- two space crafts that landed on opposite sides of

mars Mars still has a lot of ice in its ice caps Mars must have lost most of its carbon dioxide gas Mars Reconnaissance orbiter- entered mar's orbit in 2006 Venus has many of the same features as earth like craters, volcanoes, and

a lithosphere Venus still has sulfuric acid clouds which means that outgassing still

exists Apparently the entire surface of venus was repaved 750 million years ago Carbonate rocks- rocks rich in carbon and oxegen like limestone Because venus has no water, it explains why there is so much carbon

dioxide We consider the comparision is if the earths core temperature heated up,

then there would be more water vapor and clouds would then be able tohold more water vapor and the vicious cycle is called the runwaygreenhouse effect.

Unique features of earth important for life Surface liquid water Atmospheric oxygen Plate tectonics Climate stability

Ocean- provides oxygen and needed to create earths ozone Seafloor crust- mantle material rises upward and erupts to the surface

along mid ocean ridges, becoming new crust for the seafloor Seafloor crust then gets turned into the mantle due to subconduction The method by which earth regulates its temerature is called the carbon

dioxide cycle Atmospheric carbon dioxide dissolves in rain water The mildly acidic rainfall erodes rocks on eaths continents and rivers

carry the broken down minerals to oceans In the oceans the eroded minerals combine with dissolced carbon

dioxide and fall to the ocean floor making carbonate rocks

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Over millions of years the conveyor belt of plate tectonics carries thecarbonate rocks to subduction zones and subduction carries them tothe mantle,

As they are pushed deeper some of the rock melts and releasescarbon dioxide into the atmosphere through voclanoes

Global warming due to human interaction is our most serious threat.