Origin And Structure Of The Earth Earth -The only planet in the solar system to support life. Our planet has an atmosphere (ozone layer) that shields us from the harmful rays that are coming from the sun. -The only place in the known universe confirmed to host life and the only one with accessible water on the surface for the inhabitants to use. -It is made up of 70% water -It is sometimes called the "Blue Planet" Ao Sekai lol -The main reason this planet is habitable is because it has the right amount of distance from the sun. Not too cold and not too hot, just right. -It has elements that are important for supporting life like carbon and oxygen. -It provides water, oxygen, biological products, suitable weather that are important in supporting life in that world. Earth has: ! Water ! Plate tectonics ! Several layers of Atmosphere Differences or Earth from Venus and Mars: [Similarities] # They all have terrestial characteristics made from solid rocks and silicates. # They all have an atmosphere # They almost have the same time to rotate on their axis # Earth and Mars both have water # They all have carbon dioxide # All have landforms [Differences] <obvious already, no? # Venus has not water # Earth is only habitable (for now, who knows maybe elon knows?) # Venus and Mars have no oxygen # Earth is in the habitable zone of the solar system Rocks -Earth is a solid rock to a depth of 2,900km, where the mantle meets the liquid outer core. A rock is a naturally occuring solid aggregate of one or more minerals. The aggregate minerals forming the rocks are held together by chemical bonds. Grains can be different in color, texture, and sizes. # Geologists groups rocks into 3 categories: ! Igneous ! Sedementary ! Metamorphic # Petrology ! Scientific study of rocks ! Classify rocks based on how they were formed Three types of rocks: ! Igneous -Formed from hardening and cystallization of magma or molten materials that originates deep within the eart. # Two types of Igneous Rocks -Extrusive/Volcanic Rock ~Forms when magma makes its way to the earths surface as lava and cools. The cystals are very small or fine grained since the cooling process is so fast. -Intrusive/Plutonic ~It cools slowly beneath the earth's surface and are created by magma, unlike the extrusive ones, this type have very large crystals or coarse grained. # Igneous rocks are classified based on: [Composition] ! Felsic > Light in color; feidspar and silicates ! Mafic > Dark in color; magenesium and iron ! Intermediate > Between Felsic and Mafic ! Ultramafic > Very dark in Color [Texture and Appearance] ! Aphanistic > Fine grained ! Phaneric > Coarse grained ! Porphyritic > Large crystals with small crystals ! Glassy > Non-ordered soid from rapid quenching ! Pyroclastic > Composite of ejected fragments ! Sedementary -They provide information about the surface conditions that existed in the earth's past. -Particles of sand, shells, pebbles, and other fragments of materials called sediments, accumulate in layers and over long period of time harden into rocks. -Compaction due to increase of pressure of layered sediments, it binds together to form the sedimentary rock. # Three types of Sedimentary rocks [Clastic] ~Formed from accumulation of clasts; little pieces of broken rocks and shells. ~Breccia, Sandstone, and Shale [Chemical] ~Formed when dissolved minerals precipitate from a solution. ~Halite; formed when seawater body becomes enclosed and evaporates [Organic] ~Rocks formed from the accumulation of animal debris. ~Coal; formed from plant fragments ! Metamorphic -Forms pre-exisiting rocks either metamorphic, igneous, or sedimentary like quartzite, marble, slate, and phyllite. ! Metamorphism -Transformation of one rock into another # Two types of Metamorphism [Regional] ~Due to changes in pressure and temperature over large region of the crust [Contact] ~Mainly by heat due to contact with magma # Classification [Texture] ~Referes to the size arrangements and grains within the rock. [Foliation] ~Any planar arrangement of mineral grains or Structural features within the rock **Foliated > Appeared banded or layered, contains crystals. **Non-Foliated > Made up of only few minerals.