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Chapter 1 Origins OF THE Universe AND Solar System
Science Technology and Society (STS)
ICCT Colleges Foundation
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CHAPTER 1 : THE ORIGIN AND STRUCTURE OF THE EARTH
Objectives: 1 state the different hypotheses explaining the origin of the universe 2 describe the different hypotheses explaining the origin of the solar system 3 explain the current advancements/ discoveries on the solar system 4 recognize the uniqueness of the earth, being the only planet in the solar system with properties necessary to support life 5 describe the four subsystem of the earth 6 identify and describe the layers of the earth
Lesson 1: UNIVERSE AND SOLAR SYSTEM
Structure, Composition, and Age
The universe as we currently know it comprises all space and time, and all matter and energy in it.
It is made of 4% baryonic matter (<ordinary= matter consisting of protons, electrons, and neutrons: atoms, planets, stars, galaxies, nebulae, and other bodies), 24% cold dark matter (matter that has gravity but does not emit light), and 71% dark energy (a source of anti-gravity)
Dark matter can explain what may be holding galaxies together for the reason that the low total mass is insufficient for gravity alone to do so while dark energy can explain the observed accelerating expansion of the universe.
Hydrogen, helium, and lithium are the three most abundant elements.
Stars - the building block of galaxies-are born out of clouds of gas and dust in galaxies. Instabilities within the clouds eventually results into gravitational collapse, rotation, heating up, and transformation into a proto star-the hot core of a future star as thermonuclear reactions set in.
Stellar interiors are like furnaces where elements are synthesized or combined/fused together. Most stars such as the Sun belong to the so-called <main sequence stars.= In the cores of such stars, hydrogen atoms are fused through thermonuclear reactions to make helium atoms. Massive main sequence stars burn up their hydrogen faster than smaller stars. Stars like our Sun burn up hydrogen in about 10 billion years.
Birth, evolution, death, and rebirth of stars
The remaining dust and gas may end up as they are or as planets, asteroids, or other bodies in the accompanying planetary system.
A galaxy is a cluster of billions of stars and clusters of galaxies form superclusters. In between the clusters is practicallyan empty space. This organization of matter in the
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universe suggests that it is indeed clumpy at a certain scale. But at a large scale, it appears homogeneous and isotropic.
- Based on recent data, the universe is 13 billion years old. The diameter of the universe is possibly infinite but should be at least 91 billion light-years (1 light-year = 9 × 10 12 km). Its density is 4 x 10-31 g/cm 3.
Expanding Universe
- In 1929, Edwin Hubble announced his significant discovery of the <redshift= and its interpretation that galaxies are moving away from each other, hence as evidence for an expanding universe, just as predicted by Einstein’s Theory of General Relativity.
- He observed that spectral lines of starlight made to pass through a prism are shifted toward the red part of the electromagnetic spectrum, i., toward the band of lower frequency; thus, the inference that the star or galaxy must be moving away from us.
Red shift as evidence for an expanding universe. The positions of the absorptions lines for helium for light coming from the Sun are shifted towards the red end as compared with those for a distant star. This evidence for expansion contradicted the previously held view of a static and unchanging universe.
Origin of the Universe
Universe is an all space-time, matter and energy including the solar system, all stars and galaxies and content of intergalactic space, regarded as a whole.
Non-scientific Thought
Ancient Egyptians believed in many gods and myths which narrate that the world arose from an infinite sea at the first rising of the sun.
The Kuba people of Central Africa tell the story of a creator god Mbombo (or Bumba) who, alone in a dark and water-covered Earth, felt an intense stomach pain and then vomited the stars, sun, and moon.
In India, there is the narrative that gods sacrificed Purusha, the primal man whose head, feet, eyes, and mind became the sky, earth, sun, and moon respectively.
The monotheistic religions of Judaism, Christianity, and Islam claim that a supreme being created the universe, including man and other living organisms.
Scientific Thought
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Just a part of the vast universe is our solar system. It is located somewhere in Milky Way Galaxy. It consists of the sun being at the center, minor and major planets and other celestial bodies like satellites, comets, asteroids and meteoroids.
ORIGIN OF THE SOLAR SYSTEM
There are major theories that explain the origin of the solar system. 1. Nebular Hypothesis Theory. - In the 1700s Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace independently thought of a rotating gaseous cloud that cools and contracts in the middle to form the sun and the rest into a disc that become the planets. This nebular theory failed to account for the distribution of angular momentum in the solar system. - According to this theory, the sun and other celestial bodies orbiting around it where formed from a nebula- a spinning cloud of gases. These clouds are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. 2. Accretion Theory. - Accretion is the gradual increase in the size of an object by the buildup of matter due to gravity. - The accretion theory says that a protosun passing through a cloud of interstellar materials pulled this material along causing it to swirl around the protosun. As the protosun evolved into the sun, the material it accreted gradually formed the planets and other revolving bodies.
- Tidal Theory.
- According to this theory, the time when the sun about to form (protosun), a large body passing around it may have drawn some gaseous materials from it.
- The mass of gaseous materials drawn did not completely escape gravitational pull of the protosun. It continued to spin around it, eventually becoming more dense and gradually formed into planetesimals. These planetisimals give rise to the planets and their satellites.
Recent advancement/information on the Solar System
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Space exploration by means of manned and unmanned spacecrafts give us information about the solar system and beyond. Achieving spaceflight enabled humans to begin to explore the solar system and the rest of the universe, to understand the many objects and phenomena that are better observed from a space perspective, and to use for human benefit the resources and attributes of the space environment.
Exploration of Mars Since the 1960s, the Soviet Union and the U. have been sending unmanned probes to the planet Mars with the primary purpose of testing the planet's habitability. The early efforts in the exploration of Mars involved flybys through which spectacular photographs of the Martian surface were taken. The first successful landing and operation on the surface of Mars occurred in 1975 under the Viking program of NASA. Recently, NASA, using high resolution imagery of the surface of Mars, presented evidence of seasonal flow liquid water (in the form of brine - salty water) on the surface of Mars. Rosetta's Comet Rosetta is a space probe built by the European Space Agency and launched on 2 March 2004. One of its mission is to rendezvous with and attempt to land a probe (Philae) on a comet in the Kuiper Belt. One of the purpose of the mission is to better understand comets and the early solar systems. Philae landed successfully on comet (67P/Churyumov 3 Gerasimenko) on 12 November 2014. Analysis of the water (ice) from the comet suggest that its isotopic composition is different from water from Earth.
Pluto Flyby On 14 July 2015, NASA's New Horizon spacecraft provided mankind the first close-up view of the dwarf planet Pluto. Images captured from the flyby revealed a complex terrain - ice mountains and vast crater free plains. The presence of crater free plains suggests recent (last 100 millions of years) of geologic activity.
Lesson 1: EARTH AND EARTH SYSTEM
Study questions: 1. What are the major theories pertaining to the nature of expanding galaxy? Explain each. 2. Why do some scientists believe that the universe is expanding? 3. What are the major theories about the origin of the solar system? Explain each. 4. How is space exploration benefits mankind?
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LITHOSPHERE (GEOSPHERE)
- The lithosphere includes the rocks of the crust and mantle, the metallic liquid outer core, and the solid metallic inner core.
- Briefly discuss the Plate Tectonics as an important process shaping the surface of the Earth. The primary driving mechanism is the Earth's internal heat, such as that in mantle convection.
HYDROSPHERE Planet Earth has been called the "Blue Planet" due to the abundant water on its surface Over 70 percent of the surface area of the earth is covered by water. All the earth’s water, solid or in liquid form, those that are contained in glaciers, rocks, soil and the air, comprise the earth’s hydrosphere.
SOURCES OF WATER Ocean. A big portion of earth’s water is found in ocean. The oceans cover more than 70 percent of the Earth's surface and contain 97 percent of the Earth's water. If the ocean's total salt content were dried, it would cover the continents to a depth of 5 feet. Together with the atmosphere, oceans regulate global temperatures, shape weather and
climate patterns, and cycle elements through the biosphere.
Ocean Structure and Composition Like the atmosphere, the oceans are not uniformly mixed but are structured in layers with distinct properties. Pressure increases with depth as the weight of the overlying air and water increase. Atmospheric pressure at sea level is 14 pounds per square inch , and pressure increases by an additional atmosphere for every 10 meters of descent under water.
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Layers of the ocean
The Epipelagic , or sunlight, zone (so called because most visible light in the oceans is found here) comprises the first 200 meters below the surface, and is warm and mixed by winds and wave action. At a depth of about 200 meters, the Continental Shelf (the submerged border of the continents) begins to slope more sharply downward, marking the start of the Mesopelagic , or twilight zone. Here water temperature falls rapidly with depth to less than 5°C at 1,000 meters. This sharp transition, which is called the thermocline, inhibits vertical mixing between denser, colder water at depths and warmer water nearer the surface. About 18 percent of the total volume of the oceans is within this zone. Below 1,000 meters, in the Bathypelagic, or midnight, zone, water is almost uniformly cold, approximately 4°C. No sunlight penetrates to this level, and pressure at the bottom of the zone (around 4,000 meters depth) is about 5,880 pounds per square inch. Little life exists at the Abyssopelagic (abyssal) zone , which reaches to the ocean floor at a depth of about 6,000 meters. Together, these cold, deep layers contain about 80 percent of the total volume of the ocean. The deepest layer of the ocean is the Hadal Zone or Trench Zone. The deepest trench on earth is Mariana Trench, also called Marianas Trench , lies in the floor of the western North Pacific Ocean.
INLAND WATERS
Household, commercial and agricultural water supply mainly come from inland bodies of water. Two major inland waters are described below.
- Rivers A volume of a fresh flowing water across the surface of the land usually to the sea. Rivers flow in channels.
- Lakes A reservoir of relatively still water that is surrounded by land. It is formed from the accumulation of large amounts of water in natural or artificial depressions on the surface of the land. Other inland waters include ponds, spring, stream, wetlands, floodplains and reservoirs.
GROUNDWATER It is the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers. It results from the accumulation of water penetrating through small openings called pores in the rocks or soil. This process is known as percolation. Groundwater supplies drinking water, used for irrigation to grow crops and an important component in many industrial processes.
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INNER PART OF THE EARTH
The planet Earth is made up of different layers: the very thin, brittle crust, the mantle, and the core; the mantle and core are each divided into two parts. Although the core and mantle are about equal in thickness, the core actually forms only 15 percent of the Earth's volume, whereas the mantle occupies 84 percent. The crust makes up the remaining 1 percent.
Crust The crust is the outermost part of the earth and is very thin compared to the other layers. It is a part where the living organisms dwell in. It forms a very thin continuous layer that extends underneath the ocean and continents.
2 KINDS of CRUST
- Continental crust is mostly composed of different types of granites. Geologists often refer to the rocks of the continental crust as <sial= which stands for silicate and aluminum, the most abundant minerals in continental crust. Cratons are the oldest and most stable part of the continental lithosphere and are found deep in the interior of most continents.
- Oceanic crust is mostly composed of different types of basalts. Rocks of the oceanic crust are referred to as <sima= which stands for silicate and magnesium, the most abundant minerals in oceanic crust.
The Mohorovicic Discontinuity, or "Moho," is the boundary between the crust and the
mantle. The red line in the diagram shows its location.
In geology the word "discontinuity" is used for a surface at which seismic waves change
velocity. One of these surfaces exists at an average depth of 8 kilometers beneath the
ocean basin and at an average depth of about 32 kilometers beneath the continents. At
this discontinuity, seismic waves accelerate. This surface is known as the Mohorovicic
Discontinuity or often simply referred to as the "Moho."
The Moho: Image of Earth's internal structure by USGS - Mohorovicic Discontinuity (red line) added by Geology
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The Mantle It is the mostly-solid bulk of Earth’s interior. The mantle lies between Earth’s dense, super heated core and its thin outer layer, the crust. It is made up of silicates, magnesium oxide, iron, aluminum, calcium, sodium, and potassium. The mantle is divided into two layers: the upper mantle and the lower mantle.
Mantle Plumes A mantle plume is an upwelling of superheated rock from the mantle. Mantle plumes are the likely cause of <hot spots,= volcanic regions not created by plate tectonics.
The Core It is the dense center and hottest part of earth. The core is made almost entirely of iron and nickel. The Gutenberg discontinuity is the boundary between the core and the mantle. The core is made of two layers: a) Outer Core - borders the mantle. Bullen discontinuity is the hottest part of the core. b) Inner Core- is a hot, dense ball of iron. The temperature of the inner core is far above the melting point of iron.
Bullen discontinuity is the boundary separating these two layers.
Earth’s Magnetic Field Earth’s magnetic field protects the planet from the charged particles of the solar wind. Without the shield of the magnetic field, the solar wind would strip Earth’s atmosphere of the ozone layer that protects life from harmful ultraviolet radiation.
Links for Learning:
Big Ideas 3: Earth’s Systems Interact
(youtube/watch?v=BnpF0ndXk-8)
Structure of the Earth
(youtube/watch?v=4AxZ-6MOznY)
Chapter 1 Origins OF THE Universe AND Solar System
Course: Science Technology and Society (STS)
University: ICCT Colleges Foundation
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