Geology 100

Tectosilicates (Framework silicates)

form 3D network, tetrahedra share ALL oxygen ions with neighboring tetrahedra , NO CATIONS --> all connected to each other Stable, strongly bonded structure bc no cations Approx 64% of Earth's rocky crust is made up of tectosilicates, ex. Quartz (what 99% of sand is made of), Feldspar mineral group 2 types of Feldspar mineral groups (51% of crust) 1. Alkali Feldspars (39%) - Potassium Aluminum silicates 2. Plagioclase Feldspars (12%) - Sodium Aluminum Silicates

Earth's crust

thin outer layer; 40-70km thick, lighter elements w low melting temps Ex. Si, Al, Fe, Ca, Mg, Na, K combined w Oxygen These materials (other than Fe) are among the lightest of the solid elements

Mineral Identification

-hardness (Mohs hardness scale, stronger bond = harder) -cleavage (how min splits along flat surfaces, strong = poor cleavage) -fracture -luster: way mineral reflects light - streak - color of fine deposit of mineral dust left o abrasive surface, Hematite no matter color always leaves reddish brown streak -color - useless, but color of pure substances deep on presence of certain ion which strongly absorb portions of light spectrum ex. Emerald (green beryl): Chromium, Blue Sapphire (blue corundum: iron and titanium) -Density: mass per unit volume (gm/cm3 or kg/m3) --> unit, mass/volume -Specific gravity: basically same as density but different bc NO UNITS, weight of mineral in air divided by weight of equal volume of pure water at 4C -acid test: For carbonate minerals ex calcite

Moon Formation Theory

4.5 BYA Mars sized protoplanet (Orpheus) collides with Earth and produces a ring of debris around Earth that eventually becomes the moon --> Orpheus may have collided twice ++ Melting 20 mil years after Earth formed --> moon, shocked spin axis of Earth from vertical to 23deg inclination (gave us seasons) and initially sped up Earth rotation Moon's gravitational pull slows speed of Earth's spin to 24 hours

Early Earth Formation

1. 2 bodies collide at fast speed 2. mechanical XN becomes thermal XN 3. big body becomes v hot Earth 4.5 BYA = v hot, what happened in the first 1/2 bill yrs? unclear but we know it was hot little planets = planetesimals, proto-Earth - before Earth was what we know now

Proto-earth to Earth etc**

1. Accretion (accumulation/buildup) - irreg shape and v soft/mushy bc hot, homogenous (everything mixed up); after sometime it cooled of 2. Impact Event - 3. Differentiation - Earth becomes layered once it was cooler (aerodynamic, layered, reg shape) 4.5BYA (needed for life on earth) when Earth cooled --> light elements went to surface and heavier elements went to core (Fe, Au, Ag), need lighter elements for life **Differentiation occurred early in Eath's history when the planet got hot enough to melt

Kepler's 3 Laws

1. Shape of orbits: Planets are in elliptical orbits 2. Speed of planet changes as its in orbit - Regardless of where planet is, sweets out equal areas in equal times --> moves fastest when it's closest to the Sun (Perihelion) and slowest when its furthest from the Sun (Aphelion) 3. How long it takes for a planet to complete 1 orbit around Sun (orbital period) and how time deep on distance between the 2 objects - Harmonic law/"Harmony of the Worlds" Square of period of planet's orbit = cube of semi major axis of planet's orbit (Pyrs) squared=(Aau)cubed **Outer planets have further to go and move more slowly on orbits than inner plants

Differences between 8 planets

1. Size: OP larger than IP 2. Density: OP less dense than IP 3. Chemical makeup: OP: large amt of gases (H and He) and ices (CH4, H20, and NH3) and rocks within core, IP: +rocks/metals, minor amt of gases and ices OP have thick atmospheres: H, HE, CH4 (methane), NH3 (ammonia) IP have meager atmospheres at best (getting atmosphere depends on mass and temp --> since IP have small mass and are + hot, atmosphere probs dissolved over time) 4. Rate of rotation: Outer planets have a larger distance from the Sun and move more slowly than inner planets **OP have high escape velocities (bc large mass so more surface gravity, so takes more force to escape from the planet) **IP have low escape velocities (smaller masses --> less surface gravity --> takes less force to escape from planet)

What makes minerals unique

1. chemical composition 2. arrangement of its atoms 3. type of chemical bonding **around 4155 recognized minerals on Earth **when identifying minerals we go to atomic arrangements bc outside appearance can be deceiving; don't just look at exterior to identify minerals like we did 50 yrs ago, we have huge machines, takes 30 mins, v precise

4 specific reasons why Pluto is a dwarf planet

1. shares orbit w gravitationally dominant Neptune, planet has to have its own orbit 2. Not gravitationally dominant in its neighborhood, its orbit decided by Neptune's gravitational force, N has locked Pluto int into a 3:2 resonance, for every 3 N orbits, P has 2 orbits 3. Pluto's orbital plane is 17 deg from Sun's equator, all other planets w exception of Mercury (7 deg) are 1-3 deg inclined from Sun's equator 4. Hasn't cleared neighborhood of smaller objects around its orbit

Cations in Silicates

8 elements account for 98% of crystal mineral mass, 6 are cations: Other 2: Oxygen and Silicon All of these cations are light elements: Al +3 Fe +2 or +3 Ca +2 Mg +3 Na +1 K +1

Nebula

A large cloud of dust and gas in space --> becomes a disk and flatten the minute you start to rotate when rotating: 1. becomes a disk, ++ fast 2. material goes to center 3. faster, material goes in to center, too much material in center --> center of disk has high density and temp (17 mill C) 4. Ball at center becomes Sun with fusion reactions - fusion of 4 hydrogen into 1 He atom (weighs less than 4 H atoms bc you lose XN since its changing); **Sun formed by fusion process, before 1st star, universe in primordial darkness **supernova (100x our sun) explosion, last one 500 YA since e=mcsquared --> explode every 1000 yrs sends shockwaves throughout our universe bigger the star, earlier you die (++bright, burns at high rate, dies)

Cleavage

A mineral's ability to split easily along flat planner surfaces. Cleavage (unlike hardness) varies w bond strength --> strong=poor cleavage, weak = good cleavage Classified based on 1) number of planes 2) quality of surface and ease of cleaving ALL crystals of a mineral exhibit its characteristic cleavage ex. Mica = 1 plane, Feldspars: 2 perpendicular planes, Amphibole: 2 not perpendicular planes, Calcite (not perpendicular) and Dolomite = 3 planes, Galena (perpendicular) = 3 planes, Halite (perpendicular) = 3 planes **Helps identify Pyroxenes and amphiboles that otherwise look alike Described as Perfect, Good, Fair

Moon Facts

A natural satellite that revolves around a planet, our moon is large in comparison to the Earth Life requires moon, Gravity at moon's surface = 1/6 of earth, moon moving away from Earth at 1.5 in/year (3.8cm), from Earth we always see the same side, if we didn't have Moon, Earth would spin 3x as fast (day is 8 hrs) age of oldest moon rock foound = 4.5by lunar day (period of time Earth's moon completes 1 axis) is 708 hours (29.5 days) SA of moon = around SA of Africa moon has no sig atmosphere or clouds and no known active volcanos, 2 high tides and 2 low tides on Earth bc moon's gravitational pull ***Our moon is large compared to Earth (1/4 of Earth) big compared to its size and it's unique among SS planets

Anion

A negatively charged ion; large, not a lot of them O2(-2), Cl(-1), S(-2), F(-1)

Cation

A positively charged ion, small, fits between anions more of them

Crystal

A single, continuous piece of a crystalline solid typically bounded by flat crystal faces Characteristics: high symmetry and same angles ex. Halite (mineral) - also called Table salt, NaCl ex. Quartz (SiO2) - color - deceiving, has nothing to do w chemical composition of mineral, has to do with impurities ex. Pyrite or Fool's gold (FeS2) NOT gold

Oort Cloud

A spherical cloud that surrounds the solar system, approx 3 light years (30 trillion km from Sun) - edge of Sun's influence Structure: realtively dense core near ecliptic plane and gradually replenishes outer boundaries - 1/6 of 6 trillion objects in outer region, 5/6 in dense core Diff bc other debris fields (asteroid belt, Kuiper belt) are flat rings lying on orbital plane of planets but Oort Cloud is spherical, enveloping SS from all sides --> we know this bc long-period comets (unlike short period comets) come to us from all parts of the sky instead of just the ecliptic plane Between 5000 and 100,000 AU from Sun Source of long period comets

Solar system includes

Asteroids, comets, meteoroids, meteors, meteorites, 8 planets and satellites, Sun

Friction - why do things burn up on re-entry?

Back of space = no resistance, as objects fall into upper levels of atmosphere at high speeds, they cause ++ friction with the air; air in front of obj compresses and heats up sometimes to over 3,000 F -- makes objects heat up and glow Most meteors are burnt up entirely in the mesosphere around 50-85km in altitude

Inosilicates II (double chain)

Basic unit: Double chain of silicates connected by cations ex. Amphibole

SiO4 4- neutralization

Before neutralized: four O-2 and one S+4 After neutralize: four O-1, every O give -1 to the Si4+ --> each O2 has residual -1 charge --> after charge balance is -4 need to neutralize the mineral so when u touch, u don't get electrocuted

Before Differentiation Percentages vs After Differ. %

Before: Mg 13%, Si 15%, O 30%, Fe 35% After: Fe 6%, Al 8%, Si 28%, O 46%

Classifying minerals

By the type of anion, can't sort cations bc v small; can be 1 element or can be a compound Oft separated by silicates vs non silicates Silicates (SiO4)-4 Carbonates (CO3)-2 Oxides (O)-2 Sulfides (S)-2 Sulfates (SO4)-2

Meteor (shooting star)

Meteoric which burns up going through Earth's atmosphere (vaporizes)

Milankovitch cycles

Changes in the shape earth's orbit, tilt, and precession that cause glacial periods and interglacial periods. 1. Orbital eccentricity: Earth's object changes from a more circular shape to a more elliptical shape; takes 100K yrs --> Sig: summers that happen when Earth is farther from the Sun are cooler, high-latitude regions receive more insolation when the axis is steeper 2. Tilt of Earth's axis: Tilt angle changes from between 22.5-24.5 deg, takes 41K --> Sig: We have seasons bc Earth's axis isn't perpendicular to the plane of orbit 3. Precession of Earth's axis: Axis traces a conical path when a top spins --> motion/wobble = precession, takes 23K Overall Sig: combine to affect total amount of insolation (exposure to Sun's rays) and seasonal distribution of inflation that the Earth receives --> triggers short term and long term climate change

Cyclosilicates

Contain rings of linked SiO4 tetrahedra (amt of rings differ) Basic unit - ring of tetrahedra, not connected directly, connected by cation Ex. Beryl (gem name is Emerald), Tourmaline

Kuiper Belt

Def: huge icy chunks beyond SS, shaped like an ellipse, similar to asteroid belt Located: 30-50 AU from the Sun, 1 AU = 150million km (distance from Earth to Sun) Some KBOs are huge, Pluto = largest known KBO KBOs are included as Trans-Neputunian Objects (TNOs which orbit sun beyond Neptune) + comets from Oort Cloud, some short-period comets come from Kuiper Belt Significance: 1) primitive remnants of early accretion phase of SS, 2) believed that KB is source of short-period comets

Mineral

Def: 1. Naturally occurring 2. Inorganic (Organisms have no role in formation of minerals 99.9% inorganic) 3. Crystalline solid (have long range highly ordered internal arrangement of atoms) 4. Narrowly def chemical composition and characteristic pays properties (not a lot of elements) General: Mineral - basic unit when discussing rocks, usually 304 minerals in a rock Minerals used in ++ nonsciency ways, + minerals = poison NOT: Elements are NOT minerals (Ex. Ca and Mg) Milk isn't a mineral bc liq Vitamins ARE NOT minerals bc manmade Coal: nat occuring, solid, BUT organic since made out of trees and NOT crystalline (+ carbon but has other elements YES Ice IS A mineral bc nat occuring, inorganic, + water, LR atomic arrangement

Comets

Def: Icy dirtball, small, fragile, irregularly shaped, left over from formation of solar system, at times active Location: Outer solar system, longer period - Oort Cloud, shorter period: Kuiper Belt Orbit: Diff elliptical orbits (vary in distance); far from Sun = cold dball, near Sun = surfaces warm, volatile mat vaporize and form a coma (atmosphere of gas and dust surrounding nucleus) + a tail Ev: Some believe that impacts from comets affected Earth ev; comet could have brought water/some organic molecules

Meteorids

Def: Most are small and rocky; Asteroids which have broken up, comets which have shed dust (smaller frag of an asteroid or comet) Orbit: The sun

Trans-Neptunian Objects (TNOs)

Def: Objects orbiting the Sun beyond the orbit of Neptune Location: Confined to thick band around the ecliptic, occupy ring/belt around the sun (mostly in Kuiper Belt) Pluto - 2nd largest known TNO, Eris is larger

Asteroids

Def: Rocky fragments left over from formation of solar system; relat small, inactive Location: Most are in a belt between Mars and Jupiter (asteroid belt) Orbit: the sun; orbits can be influenced by gravitational tug of planets, stray asteroids affected Earth ev Size: Varies

Pluto

Def: dwarf planet in Kuiper Belt Orbit: Occupies orbital plane 17deg from Sun's equator Discovered 2/23/1930 by American Clyde W Tombaugh - America was the only country upset that Pluto wasn't a planet bc Pluto was only planet discovered by an American

Roche radius (Roche limit)

Distance which a celestial body held tg by its own gravity will disintegrate due to a 2nd celestial body's tidal forces exceeding the first body's gravitational self-attraction --> distance from planet within which a satellite turns to dust, forming rings Inside Roche radius --> orbiting material disperses and forms rings --> rings spin v fast, spiraling into the surface of the planet, so rings are DYING. Outside radius, material coalesces (ex. Moon) Just bc Earth doesn't have rings doesn't mean it never had rings (some planets have rings ex. Saturn and Jupiter are losing their rings, so Earth could have had rings) Closer to the planet, satellite's orbit will be more elliptical bc gravity

Why is understanding Earth challenging?

Earth is a dynamic body, many interacting parts (Lithosphere, Hydrosphere, Atmosphere, Biosphere, Atmosphere), complex history (4.55 bill yrs), Earth has changed throughout existence both rapid/violently and gradually and scales of sizes/space of change also varies (submicroscopic vs continental/global); interactions within Earth and space; Earth is dynamic, many interacting party

Gem name vs mineral name

Emerald (gem) = beryl (mineral) Ruby and Sapphire (gems) = corundum (mineral); rubies are red, other colors are sapphires

Earth's atmosphere

Exosphere - few particles that move into and from space Thermosphere - Temp increases w height, can rise to 1500 C, but doesn't feel warm bc low air pressure (where Inter Space Station is located) Mesosphere - where most meteors burn up after enter E's atmosp Stratosphere - has ozone layer, where volcanic gases can affect the climate Troposphere - closest to E's surface; where all weather occurs

Earth's core

Fe which was about 1/3 of early planet's material = denser than other elements and sank to form most of central core molten on outside (2270 thick) solid on inside (1216) Temp at which material mets increases w pressure --> more pressure on the inside

Galaxy

Filled w stars, interstellar gases (90% H, 10% He, 0.1% other), interstellar dust: 1% in the form of solid grains

Meteorites

Meteoroid which has survived going thru Earth's atmosphere and hits the ground

Substances that make up planets

Gases, rocks, and ices (differ by melting points) Gases (He and H) - melting points near absolute 0 (-273C or 0 kelvin) Rocks (silicate minerals and metallic Fe) - melting points above 700C Ices (NH3, CH4, CO2, and H2O) - intermediate melting points, ex. water's = 0C --> ice usually refers to solid frozen volatiles, but planetary ppl call liquid and solid volatiles ices

Scientific method

General research start based on observation, experimentation, ideas, and principle that every physical event has a physical explanation

Kepler's 3rd Law (Law of Motion)

How long it takes for a planet to complete an orbital period and how this time (P) depends on the distance (A) between the center of the Sun and the center of the planet

Theory

Hypothesis that has survived ++ challenges and has accumulated ++ experimental support; conceptual schemes that demonstrate the relationship of several hypotheses to each other or some common explanation (ex. theory of relativity, atomic theory of matter)

Sorosilicates

Isolated, double tetrahedral groups formed by two SiO4 tetrahedra sharing a single apical oxygen Basic unit: 2 tetrahedra connected to other paired tetrahedra by a cation Ex. Thortveitite

Fireball

Larger meteoroid; size varies; make cool sky displays as they break up into fragments and burn up going thru Earth's atmosphere

Kepler's 2nd Law (Law of Equal Areas)

Line connecting planet to sun sequels out equal areas in equal times, Planets move faster around the sun when close to it and slower when farther away Fastest when at Perihelion, Slowest when at Aphelion Sig: Gives quantitative statement about how fast object will be moving at any point in orbit

Chemical composition

Manner in which atoms/ions of elements are held tg (chem bond) determines many phys and chem properties displayed by minerals atoms = no charge ions - when an atom loses/gains an e to/from another atom it's called an ion positively charged ions - lose electron --> CATION (v small) negatively charged ion - gain electron --> ANION (large) Most of the space of a crystal is occupied by the anions and that cations fit into spaces between them --> ions pack tg in different ways depending on their size (cubic, tetragonal, octahedral) crystal structures are determined largely by the way anions are arranged and by the way in which cations fit between them

Meteor shower

Many matters fall thru atmosphere in a short time and in approx parallel trajectories; v intense meteor shower = meteor storm

Composition of Earth's atmosphere (up to 25km)

N2 (78.08%), O2 (25.95%), Ar (0.93%)

Nesosilicates

Neso - island in latin, Isolated tetrahedra, basic unit = 1 tetrahedron Doesn't share oxygens with other tetrahedra directly, connected w cations ex. Olivine

Silicates

Over 90% of Earth's crust, basically building block of all silicates is a silicon-oxygen tetrahedron, + dominant substances comprising Earth's mantle/crust SiO4-4 tetrahedron - geometrical form - 4 sides, 4 corners, 4 faces Anion w 4 negative charges which must be balanced by 4 positively charged cations to make an electrically neutral mineral (SiO4)-4 tetrahedron linked in 2 combos 1. ion can bond w cations (+), ex. Fe+2, Mn+2 2. or can share oxygens with other (SiO4)-4 tetrahedra

Differentiation

Perhaps + sig event on Earth, probs homogenous mixture of planetesimals and other remnants of solar nebular heavy material to interior --> lighter towards surface (bringing heat to surface where it radiates into space) initiated escape f even lighter gases from interior --> atmosphere and oceans were created --> today gases still escape from hot springs and volcanic eruptions' Impact event (Before): when 2 planetesimals hit --> bigger and bigger --> huge impact/pieces of rock hitting Earth

why pluto isn't considered a planet

Planet = celestial body that orbits Sun, has sufficient mass to assume hydrostatic equilibrium (nearly round) shape, clears neighborhood around orbit Dwarf planet - orbits Sun, sufficient mass to assume hydrostatic equilibrium (nearly round) shape, HASN'T cleared neighborhood of smaller objects around orbit, isn't a satellite therefore, Pluto and other TNOs are not planets , Internat Astronomical Union (IAU) def isn't accepted by everyone

OP vs IP atmosphere - dep on temp and escape velocity (based on mass)

Planets ability to keep atmosphere depends on 1) surface temp and 2) escape velocity (mass) Temperature heats up gases and rocks --> rocks not affected, gases become agitated --> IP get hot (closer to Sun) might have had atmosphere in the beginning but lost it bc of escape velocity while OP kept it) 1. Molec motion of gas depends on temp, so cold OP aren't hot enough to get moving at the speed necessary to escape whereas gases escape from IP IP are hot --> lost atmosphere over time OP are cold --> kept atmosphere 2. Escape velocity - minimum speed needed for an object to escape form the gravitational influence of a massive body --> can escape if it reaches scape velocity IP (5400-25,000mph) OP (45,000-143,000mph) **More difficult for gases to evaporate from OP bc they're cold (so gases don't get agitated enough to move) and have larger gravitational force (escape velocity) so can't escape, moon can't hold onto gases --> can't retain atmosphere

SiO4 4- Polymerization (Silicon-Oxygen Tetrahedron Polymerization)

Polymerization: connect small things to make bigger ones (polymers); possible bc of the residual charge Silicates divided into several classes based on how silica tetrahedra are arranged

What makes gems special? also gold

Rare beauty - need to have: beauty, transparency, brilliance, durability, and rarity --> diamonds are not forever geologically speaking but they're special 4 C's - cut, color ,carat, clarity Carat: unit of weight for precious stones/pearls = 200mg= 1/5g Karat = measure of purity in gold: 24K = pure gold, 18K = 75% gold with 25% copper etc White gold isn't platinum, it's gold and palladium

Polymorphism (also called Allotropism/Isomerism)

Same chemical composition, different crystal structure (bc of changes in temp/pressure) ex. Polymers of C: Diamond, graphite (dependent on environment) Diamond v hard bc C atoms form 3D network with strong covalent bonds Graphite - carbon sheets connected by covalent bonds, separate sheets are connected by weak (pi?) bonds --> when u write, ur breaking the bond and leaving flakes on paper ex. Polymers of CaCo3: Calcite, Aragonite ex. Polymers of Iron Sulfide (FeS2): Pyrite (Fool's Gold), Marcasite

Inosilicates - I (single chain)

Single chain Basic unite: single chain silicates connected by cations ex. Pyroxene

8 planets (Mercury, Venus, E, Mars, J, S, U, N) Outer planets/Jovian planets: JSUN Inner Planets/Terrestrial planets: Mer-Mars

Sun - hub of rotating system of 8 planets, their satellites, asteroids, comets, and meteoroids 99.85% of our SS mass is contained in the Sun, remaining 15% mostly mass of 8 planets Tethered in elliptical orbit around Sun, all travel in same direction Lie in orbital plane within 3deg from Sun's equator with the exception of Mercury (7 deg)

Hypothesis

Tentative explanation based on data collected thru observations and experiments

Far side vs Near side

The far side of the moon is the side that is not exposed to Earth's view due to tidal coupling. The far side is much lighter in appearance, owing to the absence of maria, has + craters Near side (WHAT WE SEE) - highlands and maria (more maria, les craterS)

synchronous rotation

The state at which the Moon's orbital and rotational periods are equal. (time body takes to rotate on its axis = same time it takes to make 1 orbit --> keeps the same hemisphere pointed at the body it's orbiting) Moon's SR caused y=by unsymmetrical dist of mass in the moon which allows Earth's gravity to keep 1 lunar hemisphere turned towards Earth Moon's synchronous rotation makes only the near side of the moon visible to Earth

Phyllosilicates (sheet silicates)

Two-dimensional sheet connected by cations basic unit: sheet silicates; all clay minerals = sheet silicates ex. serpentine mineral group, clay mineral group, mica mineral group, ex. Mica

Universe and SS age

Universe is older and bigger than our SS; Universe around 14 bill (13.8) yrs old, SS is around 4 bill yrs old --> spiral galaxy, we live in the Milky Way, light year = measure of distance

Non-silicates

V wimpy, can't build an earth wit them (can't have Earth made of Au) --> v weak chemically and physically Occur in upper part of the crust humans = wimpy, need wimpy minerals --> for our benefit Earth needs strong and flexible minerals bc of temp (core = 5000 C) and pressure 1. Native elements No charged ion S, Diamnd/Graph (C) 2. Oxides (O)-2 Hematite (fe2o3),Corundum (Al2O3), Spinel (MgAlO4) 4. Hydroxides (OH)- 4. Halides Cl-, F-, Br-, I- Halite (NaCl), Fluorite (CaF2) 5. Carbonates (CO3)-2 Calcite/Aragonite (CaCO3)-secreted by org inside shells 6. Sulfates (SO4)-2 Gypsum(CaSO4.2H20) 7. Sulfides (S)-2 Galena (PbS) Pyrite/Iron sulfide (FeS2)

Earth's mantle

between the core and the crust, consists of intermediate density rocks (compounds of oxygen w magnesium, iron and silicon) Bulk of solid Earth (2900 km thicc)

Layers of the Earth

crust (under continent), mantle, liquid outer core, solid inner core

Kepler's 1st Law

each planet orbits the sun in a path called an ellipse with the sun at one focus 3 basic properties 1. Ellipse has 2 foci - sum of distance to foci from any point on the ellipse is constant 2. amount of flattening on eclipse = eccentricity --> flatter=more eccentric, measured 0-1, circle has eccentricity of 0 3. Longer axis - major axis, shorter axis - minor axis, half of major axis - semi major, half of minor axis - semi minor axis Size of ellipse = semi major axis Shape of ellipse = eccentricity --> distance between 2 foci decided by length of major axis Elliptical orbits of planets have v small eccentricities (almost 0), so we can think of them as almost circular/utilize idea of uniform circular motion to analyze planetary motion Earth's = 0.0167

Chemical bonds

manner in which atoms/ions are held tg determines many chem and physical mineral properties ionic bond - formed by electrical attraction between oppositely charged ions, intermediate strength ex. NaCal (Na +1, Cl -1) rigid bond Over 90% of all minerals are ionic compounds Both have filled shells when NA gives up an electron to Cl --> forms halite (table salt) covalent bond - form compounds by sharing electrons, strongest bonds, ex. Diamond (C) even more rigid bond Share electrons so all have filed shells metallic bond - atoms of metallic elements, which tend to lose electrons, pack tg as cations while freely mobile electrons are shared and dispersed among the ions (ex. metal copper) very weak. flexible can make these bonds into sheets! Can't do that w NaCl (would break) good conductors of heat/electricity bc metallic bonds (valence electrons move, electrons moving = electricity) nuclei and inner shells of electrons float in a "sea" of free electrons --> electrons stream thru the metal if there's an electrical current (nucleus doesn't have as much control over valence electrons bc atom is v large since metals are large and in the middle of the periodic table)

Moon's surface

maria (seas), craters, & highlands dark and light surfaces because of rocks, light = highlands which rock called anorthositic (intrusive igneous rock 90-100% plagioclase feldspar) dark = Maria and are basaltic (volcanic) maria often coincide w lowlands, but lowlands aren't alays covered by Maria dark, lightly cratered maria are concentrated on nearside of Moon bc crust is 50 km thicker on the far side highlands older than maria bc have ++ craters

Mineral Identification - hardness

measure of ease w which mineral's surface can be scratched --> deep on chemical bonds (stronger = harder) Use Mohs Hardness Scale: 1. Talc, Graphite 2. Gypsum --Fingernail =2.5 3. Calcite -- Copper penny = 3.5 4. Fluorite 5. Apatite --Glass-steel 5.5 6. Orthoclase -- steel file 6.5 7. Quartz 8. Topaz 9. Corundum 10. Diamond

Formation of Solar System (Nebular hypothesis)

nebula - cloud of gas and dust; 2nd or 3rd generation nebula forms from H and He left over from big bang as well as heavier elements produced by fusion reactions in stars/during explosions of stars Planets formed from rotating disk of dust and gases that surrounded the Sun --> growth of planets began as solid bits of matter began to collide and clump together Inner SS --> Temps so high that only metals and silicates can form from solids (too hot for ices/gases) --> innermost parents grew ++ from high melting point substances Frigid outer reaches --> cold enough for ices/gases to form --> OP grew from metals/silicates and large amount of ices --> OP became large noun ht gravitationally capture even lightest gases (H and HE), thus became "giant" planets ++ matter in original nebula concentrated in photo-Sun --> disk of gas and dust remained to envelop it (less dense and cooler esp in outer regions than the proto-Sun) disk began to cool --> gases condensed (became liquids/solids) --> gravitational attraction caused materials to clump tg in sticky collisions as small km size chunks (planetesimals) -->planetesimals grow by collisions--> irreg shaped photo-Earth develops (interior heats up and becomes soft) --> gravity makes Earth into a sphere --> Differentiation separates Earth into core and mantle

Regolith

over time, impact of asteroids/comets have pulverized Moon surface --> finely grained layer called "regolith" thickness: 2m beneath younger maria-20m beneath highlands regolith imp bc stores info about the sun. Atoms which form solar wind (+He,Ne,C,N_ hit lunar surface and are in mineral grains --> can examine regolith and see whether Sun activity has changed w time Gases of soalr wind could also help w lunar bases since O2, H (for water), C, and N could be useful for fuel and are essential for life

Moon and Earth relationship

without Moon, we'd only have cephalopods (shrimp) Moon protects us from meteorites