CPE 3 Flashcards

Question

Roche Limit

Answer 1

Roche limit is distance at which a satellite begins to be tidally torn apart. Consider M with 2 satellites of mass m and radius r orbiting at distance R. Roche limit is reached when m is more attracted to M than to m. Occurs when Ftidal ≥ Fbinding

Answer 2

1. Very massive stars are rare & distant. o Probability of massive star coming close to another star is therefore very low. o Sun’s nearest companion is Proxima Centauri. 2. Rotational period of Sun & Jupiter should be similar if Jupiter’s material was from Sun. o Not the case (Psun ~ 26 days and Pjupiter ~ 10 hours). 3. In 1935, Henry Russell argued that it is not possible for the material from the Sun to acquire enough AM to explain Mercury, let alone the other planets. 4. Spitzer (1939) noted that material with solar densities & temperatures would give a minimum mass for collapse of ~100 times that of Jupiter.

Answer 3

Young star about 20 million years old that is located 63 light years away. -appears to be a young planetary system in the making & supports the standard model of solar system birth, which supposes that planets accrete from a disk of dust & gas surrounding a young star

Answer 4

At the heart of the Orion Nebula lies a complex of molecular clouds where abundant star formation is occurring today. The clouds are illuminated by a flood of ultraviolet light emitted by four bright stars, collectively called the Trapezium. More than 150 protoplanetary disks have been found in this mosaic of HST images.

Answer 5

4.56 billion years old, older than the moon which is 4.5 billion years old.

Answer 6

4.56 and 4.5 by: Accretion to create the first earth… a “magma” earth (100 million-year-period) 4.5 by: Earth was hit by a giant bolide (before 4.47 by) that remelted it and led to the formation of the moon 4.5 and 4.4 by: Mainly cooling and differentiation: Gravity pulled the denser materials toward the core when the Earth was still molten

Answer 7

4.56 and 4.5 by: Accretion to create the first earth… a “magma” earth (100 million-year-period) 4.5 by: Earth was hit by a giant bolide (before 4.47 by) that remelted it and led to the formation of the moon 4.5 and 4.4 by: Mainly cooling and differentiation: Gravity pulled the denser materials toward the core when the Earth was still molten

Answer 8

Early atmosphere would have been similar to the Sun--mainly H & He, but this atmosphere was lost quickly for 2 reasons: (1) Gravity of the modest size earth was not strong enough to prevent such light gases from escaping to space, particularly since the early earth was hot! (2) Appears that around 30 m.y. after the earth’s formation, it was struck by a large object, the size of Mars. Result: the origin of the moon & loss of earth’s early H, He atmosphere EARTH IS LITERALLY HOT - surface of the earth during this period was extremely hot with numerous volcanoes - it was under near constant bombardment by objects of varying sizes - slowly, it started to cool down & the second atmosphere began to form.

Answer 9

A new atmosphere was established by the outgassing of volcanoes…the mixture of gases was probably similar to those of today’s volcanoes: H20 vapor (roughly 80%) CO2 (roughly 10%) N2 (few percent) Small amounts of CO, HCL, HS (Hydrogen Sulfide), SO2, CH4 (Methane), Ammonia (NH3), & other trace gases. Virtually no oxygen in that second atmosphere. Thus, no ozone layer, so ultraviolet radiation flooded the earth’s surface. With a huge influx of water vapor and the cooling of the planet, clouds and earth’s oceans formed. At that time the sun was about 30% weaker than today…why didn’t the earth freeze over? The apparent reason: so much CO2 so there was a very strong greenhouse effect.

Answer 10

In the first two billion years of the planet’s evolution, the atmosphere acquired a small amount of oxygen, probably by the splitting of water (H20) molecules by solar radiation. The evidence of this oxygen is suggested by minor rust in some early rocks. The oxygen also led to the establishment of an ozone layer that reduced UV radiation at the surface. With the rise of photosynthetic bacteria (cyanobacteria) and early plants, oxygen levels began to rise rapidly as did indications of rust in rocks Between 2.5 billion years ago to about 500 bya, 02rose to near current levels. While O2 was increasing, CO2 decreased due to several reasons: (1) In photosynthesis CO2 is used to produce organic matter, some of which is lost to the system (e.g., drops to the bottom of the ocean or is buried) (2) chemical weathering, which removes CO2. At first this happened without life, but the process was sped up tremendously by living organisms. Marine organisms would incorporate carbonate into their shells, which would fall to the ocean bottom when they died--- thus, removing them from the system for a long time. The bottom line…CO2 was being removed from the system. MORE CHANGES Sulfur compounds were taken out of the atmosphere as acid rain and were deposited on the ground as sulfates. N2 gas increased slowly but progressively since it was relatively inert. Current composition of the atmosphere was established approximately a billion years ago. A PROBLEM With lower CO2levels the earth became more susceptible to ice ages when solar radiation decreases due to orbital variations. It appears that around 750-550 million years ago the earth cooled down and became nearly entirely glaciated.

Answer 11

Volcanoes were still putting CO2 into the atmosphere. Weathering was greatly reduced…since little liquid water. So CO2 increased until the greenhouse effect was so large the earth warmed up. Once warming started it would have happened very rapidly.

Answer 12

The climate has not been constant, with warm periods interrupted by ice ages. Much of the variability forced by changing solar radiation due to periodic changes in the earth’s orbital characteristics and tilt (Milankovitch cycles) and major volcanic eruptions (putting out massive CO2 that caused warming.

Answer 13

The hydrosphere is the total amount of water found on Earth. This includes water in various forms---- whether in ice, vapor, or liquid, found on or below the surface of the Earth and in gas in atmosphere. Water covers 70% of the entire surface of Earth, and most of it is ocean water. Only 3 % of Earth's water is fresh: two-thirds are in the form of ice, and the remaining one-third is present in streams, lakes, and groundwater. The oceans are important sinks for CO2 through direct exchange with the atmosphere and indirectly through the weathering rocks. Heat is absorbed and redistributed on the surface of the Earth through ocean circulation. Water has been associated with the existence of life. When water or traces of water are found in other planets, the possibility of life is always speculated. It is critical component of most organisms that drying up would mean dying. The Importance of Water 1. Water could be in liquid form, not just solid and gas. 2. Water has a neutral pH. 3. Water is high specific heat. 4. Water is a good conductor of heat and energy. 5. Water is a universal solvent. Water circulates everywhere on Earth. This circulation is made possible by the interaction of energy and matter that allows the transformation of water from one phase to another, allowing it to circulate and travel to different regions of Earth. Because of the water cycle, different life processes are maintained. All waters found on Earth are natural but not everything is considered safe for drinking. In fact, less than 35 of the world's waters are considered potable. The waters on Earth are divided into two groups: Surface water and groundwater. Surface water, as the name implies, is water found on Earth's surface. Surface water and groundwater differ in the types and amount of minerals found in them. Surface water may be either marine water and freshwater. Marine water has higher salt content and is found in large bodies while freshwater is those have lower salt content. Groundwater is water beneath Earth's surface where there are spaces on the soil or fractures in rocks. The aquifer is the underground layer of water-bearing rocks and it acts as a reservoir for groundwater and may contain large amounts of minerals such as magnesium, calcium, etc.

Answer 14

The biosphere is the subsystem that comprises all living things, including those which have not yet been identified. In fact, there are more life-forms unknown to humans than those that have been identified. Life exists in all the subsystems of Earth- on land, in water, and in air. It is the regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms. * Biosphere is a closed system that makes up all the living components of Earth. * The pyramid is constructed according to the rate at which food material(in the form of energy) passes through the food chain - It covers all ecosystems - from the soil to the rainforest, from the mangroves to coral reefs, and from the plankton-rich ocean surface t the deep sea. - For the majority of life on Earth, the base of the food chain comprises photosynthetic organisms. During photosynthesis, CO2 is sequestered from the atmosphere, while oxygen is released as a by-product. The biosphere is a CO2 sink, and therefore, an important part of the carbon cycle. -Sunlight is necessary for life. THE ORIGIN OF THE BIOSPHERE Life on Earth is presumed to have begun around 3.9 million years ago from a single primitive living creature. How it started and evolved up to this time. Therefore, many theories emerged that attempt to explain the origin of life on Earth. 1. The theory of primordial soup. Scientists have held on to the theory of primordial soup. Scientists have held on to the theory of the primordial soup, which explains how life began on Earth. It states that life began from nonliving matter such as simple organic compounds. It was believed that the primitive Earth contained chemicals such as methane, water, ammonia, and hydrogen gas that accumulate in a soup at certain areas viable for transformation. Over time, the first known creatures to have inhabited Earth were the single-celled microorganisms, bacteria, and archaeans. 2. Deep-sea vent theory. This theory presupposes that life began to on the surface of Earth but deep down in the sea in areas known as marine hydrothermal vents. Hydrothermal Vents release boiling hot fluids mixed with toxic chemicals and heavy metals. Hydrogen sulfide is the main compound spewed out from cracks or fissures on the ocean floor. Certain bacteria or primitive microbes grow around the vents. The bacteria absorb hydrogen sulfide that streams from the vents to create simple sugars from their food in a process known as chemosynthesis. In 1990, the discovery of nanotubes ( organisms smaller than bacteria that contain DNA and live rocks) and the subsequent discovery of an entirely new ecosystem that exists in the deep-sea vent support this theory which was proposed by Thomas Gold (1920-2004) in his paper entitled 'The Deep Hot Biosphere (1992). 3. Panspermia. This hypothesis proposes that life on Earth actually began somewhere in the universe. Life - forms could have been carried by meteorites, asteroids, or comets as they made a cosmic impact on Earth. The biosphere is a closed system that makes up all the living components of Earth. In this system an organism can consume another organism to allow energy to circulate to the ecosystem (see Figure 2.8.1 ). Life exists in all the subsystems of Earth--- on land ( geosphere ), in water ( hydrosphere ), and in air ( atmosphere ). A key component to Earth's systems, the biosphere interacts and exchanges matter and energy with the other systems. It helps drive the biogeochemical cycling of carbon, nitrogen, phosphorous, sulfur, and other elements. Through an ecological point of view, the biosphere encompasses Earth's ecosystem and performs all manner of biological functions such as respiration and photosynthesis.

Answer 15

Scientists divide the Earth into three layers based on composition (chemical sections) * Crust – the thinnest layer of the Earth (5- 20km thick) made entirely of light elements like silicon * Mantle – makes up 68% of the earth’s mass, (2900km thick) made of rocks of medium density * Core – the innermost layer, has a radius of 3400km and composed of the densest elements such as nickel and iron

Answer 16

* The crust makes up less than 1% of the Earth’s mass. * There are two types of crust: – Continental crust, and oceanic crust. *Is the outermost solid part of the earth, normally about 8-40 kms thick. *It is brittle in nature. *The thickness of the crust under the oceanic and continental areas are different. Oceanic crust is thinner (about 5kms) as compared to the continental crust (about 30kms). * Continental crust is about 30- 35 km thick. * It is also made up of lightweight and low density materials. * Oceanic crust is much thinner – it’s only about 5 km thick! * It is also made up of heavier and denser materials. Major constituent elements: *Silica (Si) and Aluminium (Al) and thus, it is often termed as SIAL (Sometimes SIAL is used to refer Lithosphere, which is the region comprising the crust and uppermost solid mantle, also).

Answer 17

* The mantle is about 2900 km thick. * It is made up of dense materials, which are rich in iron. * The mantle is semifluid; the molten rock flows very slowly, which lets the solid plates move on top. * The discontinuity between the crust and mantle is called as the Mohorovicic Discontinuity or Moho discontinuity. * Nearly 84% of the earth’s volume and 67 - 68% of the earth’s mass is occupied by the mantle. * The major constituent elements of the mantle are Silicon and Magnesium and hence it is also termed as SIMA The Lithosphere: * The uppermost solid part of the mantle and the entire crust constitute the Lithosphere. * The lithosphere is cool, solid and rigid. * It is divided into many smaller pieces called tectonic plates. The Asthenosphere: * is a highly viscous, mechanically weak and ductile, deforming region of the upper mantle which lies just below the lithosphere * is semi-fluid, molten rock * allows the tectonic plates to move on top The Asthenosphere This motion is essential to our Earth‘s appearance. The asthenosphere is the main source of magma and it is the layer over which the lithospheric plates/ continental plates move (plate tectonics). *The discontinuity between the upper mantle and the lower mantle is known as Repetti Discontinuity. *The portion of the mantle which is just below the lithosphere and asthenosphere, but above the core is called as Mesosphere.

Answer 18

*It is the innermost layer surrounding the earth’s center. *The core is separated from the mantle by Guttenberg’s Discontinuity. *It is composed mainly of iron (Fe) and nickel (Ni) and hence it is also called as NIFE. *The core is the densest layer of the earth with its density ranges between 9.5-14.5g/cm3. Outer Core * The outer core is composed of dense liquid metallic elements. * Mainly nickel and iron. Inner Core * The inner core is composed of solid nickel and iron. * This is due to the immense pressure found at the center of the Earth *The discontinuity between the upper core and the lower core is called as Lehmann Discontinuity. *Barysphere is sometimes used to refer the core of the earth or sometimes the whole interior

Answer 19

* N - most abundant gas, does not react readily with other substances. * O - reacts chemically as fires burn, iron rusts, and plants and animals respire. * CO2 - which by some models formed as much as 80 percent of Earth’s early atmosphere, is a trace gas in the modern atmosphere, with a concentration of only 0.035 %

Answer 20

* “Tropos” means turning or changing * layer of air closest to Earth & considered the densest among the layers because of the weight of all other layers * virtually all of the water vapor & clouds exist in this layer * Temperature goes from warm to cold as you increase in altitude. * This is where all weather occurs. * The tropopause is the boundary between the troposphere and the stratosphere above.

Answer 21

* “Strato” means layer or level * Contains the Ozone layer (serves as shield against the sun’s UV radiation) * From 10km to 50km above sea level. * Planes often fly here. * Temperature goes up as you rise in altitude due to the ozone absorbing the suns heat. * This boundary between rising and falling temperature is the stratopause, the ceiling of the stratosphere.

Answer 22

* “Meso” means middle & is the middle layer of the atmosphere. * Protects the earth from planetary debris (e.g. meteoroids) * Temperature goes down as altitude goes up. * The ceiling of the mesosphere is the mesopause. * Considered the coldest region

Answer 23

* “Thermo” means heat. * considered the hottest layer because it absorbs highly energetic heat from the sun * Temperatures reach up to 1,800 degrees Celsius or 3,272 degrees Fahrenheit. * 80km above sea level and has no definite end. * As you increase in altitude, temperature goes up. * Here the atmosphere absorbs high-energy X-rays and ultraviolet radiation from the Sun.

Answer 24

* from the lower part of the thermosphere * Called ionosphere because suns energy heats molecules to become ions. * Temperature goes up as you increase in altitude. * Known for causing aurora borealis. * Most collision of oxygen and nitrogen particles are electrically charged by the solar wind. * Energy released during collisions causes the colorful glow around the poles called auroras. NORTHERN LIGHTS/aurora borealis– witnessed in northern regions like Arctic & Northern Canada Aurora australis – seen in the Southern regions like Antarctica and Southern Australia

Answer 25

* The uppermost layer of the atmosphere * Layer of very diffuse gas that overlies the thermosphere and thins upward into the vacuum of space * Not considered as another layer but it separates Earth’s atmosphere from interplanetary space. * Second layer of the thermosphere. * Satellites orbit Earth in this layer.

Answer 26

These impacts can be single events, temporary changes, or ongoing change Single event example: meteorite impact that causes massive global extinction Ongoing, steady process (example: Erosion)

Answer 27

* Biogeochemical cycle- compound is changed and moved throughout the Earth’s spheres * Carbon is commonly called the “building block of life” * Carbon is not just a solid- it forms gases such as CO2 and Methane Carbon Into the Atmosphere * Living things breathe it out * Carbon based things (i.e. trees) burn * Diffuses out of oceans * Volcanoes erupt– Number 1 source of CO2 into the atmosphere Carbon From the Atmosphere * Oceans dissolve 40% of CO2 in the atmosphere from fossil fuels * Wave action dissolves CO2 into ocean * Photosynthesis- plants breathe it in, and breathe out oxygen (phytoplankton do this in ocean water) Other ways CO2 is shared… * Carbon stored in plants is passed on to another organism when eaten (food chain) * Organisms die and decomposition puts carbon into the ground creating fossil fuels (oil, coal, etc.)

Answer 28

* Water and carbon Cycles are like wheels * Energy Cycle is like a balance – Energy that comes in must equal the energy that comes out * about 40% is reflected back into space without being changed * the remaining energy is used within the Earth system * as it moves through the system, it is changed. With every change, a little is lost to the system. Sources of Earth’s Energy 1. Solar energy- 99.895 % * Comes from nuclear fusion reactions in the sun * Drives wind, ocean currents, waves * Source of energy that causes rocks to weather forming soil 2. Geothermal energy- 0.013 % * Comes from the Earth as radioactive materials decompose * Drives the movement of the continents, powers geysers, earthquakes, and volcanoes 3. Tidal energy- 0.002 % * The result of the pull of the moon on the Earth’s oceans * Slows down Earth’s rotation and causes the oceans to bulge

Answer 29

* Albedo is the percentage of energy that is reflected back into space without being changed * Earth’s average albedo: 30% * Forest has low albedo: 5-10% * Desert has high albedo: 50% * Fresh snow: 80-90% * Humans can alter the albedo of an area, which affects the Earth’s energy budget * We can burn fossil fuels which puts CO2 in the air, or plant trees, which takes CO2 out of the air * Damming a river lengthens the amount of time it takes water to go through the water cycle

Answer 30

- describe the natural forces that influence the shape and structure of the planet -has two categories: EXOGENOUS (external) processes & ENDOGENOUS (internal) processes

Answer 31

1. WEATHERING – the disintegration of rocks, soils, & minerals together with other materials through contact with Earth’s subsystems Physical weathering – breakdown of rocks by mechanical forces concentrated along rock fractures Chemical weathering – process by which rocks break down by chemical reactions 2. EROSION – process by which Earth’s surface is worn away by wind, water, or ice - takes place when there is rainfall, surface runoff, flowing river, seawater intrusion, flooding, freezing, thawing, hurricane, wind, etc. 3. MASS WASTING – movement of material on a downslope terrain due to gravity - usually happens in slopes, is dangerous, and may occur in areas that can trigger mass movement a. Debris flow b. Mud flow c. Slumps - move down from higher elevations without help of water - slowly moving of combined soil & water down the mountain - slow downslope movement of loosely consolidated rock & soil layers 4. SEDIMENTATION – accumulation of materials such as soil, rock fragments, and soil particles settling at the bottom -usually occurs in stream and sea erosion

Answer 32

1. MAGMATISM – happens when magma is generated & develops into igneous (magmatic) rocks can take place either under the surface or on the surface of Earth to become part of the crust 2. VOLCANISM/ PLUTONISM – process that usually happens after the magma is formed Magma tries to escape from the source through openings such as volcanoes or existing cracks on the ground 3. METAMORPHISM – process of changing the materials that make up a rock 2 types: Contact metamorphism (change because of heat) & regional metamorphism (happens in a larger area) TYPES OF STRESS INFLUENCING ROCK BEHAVIOR 1. SHEARING – some portions of a plate may break away in diff. directions 2. COMRESSION – rocks push or squeeze against one another where the stress produced is directed toward the center 3. TENSION – rocks are pulled apart 4. CONFINING – crust becomes compact, making it look smaller

Answer 33

Alfred L. Wegener * Geologist Alfred Wegener noticed similar rocks & fossil remains were found on continents which seemed to fit together * He called this “super” continent called Pangaea * In 1912 Wegener published the first version & died defending his theory

Answer 34

Why didn’t people believe in continental drift? * People couldn’t imagine how the earth could be millions of years old * People couldn’t imagine a force great enough to move the continents * He could not find the force that was causing the continents to drift. BUT by the 1960’s evidence would prove continental drift is somehow TRUE and…. the story continues…

Answer 35

Harry Hess - 1960s – new ocean basins form from volcanism – ocean floor forms IN BETWEEN pieces that have split – The Sea floor spreading theory states that new ocean crust is being created at mid-ocean ridges (which are large mountain chains underwater) and destroyed at deep-sea trenches.

Answer 36

Convection Currents occur within the mantle of the earth when hot magma rises and cool magma sinks. - Arthur Holmes (British geologist) suggested the idea of thermal convection as the driving force for the movement of continental This is a model of sea floor spreading at a divergent boundary called a mid ocean ridge.

Answer 37

The Earth’s crust and upper mantle (Lithosphere) are broken into sections called plates A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust. Plates move around on top of the mantle like rafts

Answer 38

The theory that pieces of Earth’s lithosphere are in constant motion, driven by convection currents in the mantle. * Plates move slowly in different directions ❑Cause different geologic events (like earthquake, volcano, etc.) Convection Currents in the mantle move the plates as the core heats the slowly-flowing asthenosphere (the elastic/plastic-like part of the mantle). FAULT – Breaks in Earth’s crust where rocks have slipped past each other.

Answer 39

A plate boundary where two plates move away from each other Rock gets THIN in the middle as it is pulled apart. This STRESS is called tension. A Normal Fault (fault is a break in Earth’s crust) Rock drops down as it breaks * A geologic feature or event… May form RIFT VALLEYS on continents SEA-FLOOR SPREADING in the ocean Happens on land & under H2O Features of Divergent Boundaries * Mid-ocean ridges * rift valleys * fissure volcanoes

Answer 40

A plate boundary where two plates move towards each other. Boundaries between two plates that are colliding * Places where plates crash (or crunch) together or subduct (one sinks under) What happens when the rock is squeezed from the Stress of Compression? * A REVERSE FAULT * Rock is forced upward as it is squeezed.

Answer 41

Ocean plate colliding with a less dense continental plate Subduction Zone: The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary. VOLCANOES occur at subduction zones Example: Andes Mountains, South America

Answer 42

* Ocean plate colliding with another ocean plate * The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH Example: Aleutian Islands, Alaska

Answer 43

* A continental plate colliding with another continental plate * Have Collision Zones: –A place where folded and thrust faulted mountains form. * May form Mountain Ranges. These are Folded Mountains, like the Himalayas or the Rockies.

Answer 44

A plate boundary where two plates move past each other in opposite direction. * Rock is pushed in two opposite directions (or sideways, but no rock is lost) * This stress is called SHEARING * May cause Earthquakes when the rock snaps from the pressure. * A famous fault @ a Transform Boundary is the San Andreas Fault in California. What happens when the rock is sheared (or “cut”) from the Stress of Shearing? * A STRIKE-SLIP FAULT * Rocks on each side of the fault slip past each other as they break.

Answer 45

In 1956, Abraham Ortelius (1527- 1598) observed and presupposed that the shapes of the continents on both sides of the Atlantic Ocean seem to connect to each other. It was as if Africa was torn away from Asia and Europe. With the absence of valid measurements and proofs, the only speculation he could provide was that earthquakes and flooding may have made the separation possible. As early as 1929, Arthur Holmes (1890- 1965), a British geologist, suggested the idea of thermal convection as the driving force for the movement of the continents. The concept of thermal convection, as Holmes put it, is based on the fact that as a substance is heated, its density decreases and rises to the surface until it is cooled and then sinks again. the repeating process of heating and cooling may produce a current that is strong enough to make the continents move. Holmes further suggested that thermal convection works like a " conveyor belt " where the pressure that goes up could break apart a continent. The broken pieces can be carried by the same currents to opposite directions. In the later years, the concept of thermal convection was changed to mantle convection currents to specify that the heat is actually radiating from the mantle.