ELSC 01 - Origin and Structure of the Earth PDF

Origin and Structure of the Earth Earth and Life Science Formation of the Universe The Big Bang theory states that roughly 13.8 billion years ago, all the matter in the universe can be found in a single contact point. The contact point, called a Singularity, then exploded wh...

Origin and Structure of the Earth Earth and Life Science Formation of the Universe The Big Bang theory states that roughly 13.8 billion years ago, all the matter in the universe can be found in a single contact point. The contact point, called a Singularity, then exploded which caused the expansion of the Universe. It is believed that the expansion of the Universe continues up to this day. Formation of the Universe The Steady State theory states that the Universe is expanding, and new matter is created to fill the empty spaces caused by the explosion. Formation of the Universe The Plasma Universe theory states that the universe has no beginning and no foreseeable end. The electric and magnetic forces of plasma is what organized the matter in the Universe into star systems and other large observed structures. However, the observations come from laboratory experiments rather than direct observations. Formation of the Sun and the Solar System Formation of the Sun About 4.5 billion years ago, waves of energy traveling through space pressed clouds of hydrogen and helium closer together, and gravity caused them to collapse in on themselves and then start to spin, the first steps of how the solar system formed. Formation of the Sun The spin caused the cloud to flatten into a disk like a pancake. In the center, the material clumped together to form a protostar that would eventually become the sun. Formation of the Sun The young protostar was a ball of hydrogen and helium not yet powered by fusion. Over tens of millions of years, the temperature and pressure of the material inside increased, jumpstarting the fusion of hydrogen that drives the sun today. Formation of the Solar System Accretion happened in the disk that surrounded the Sun, which formed the planets and other celestial bodies. Accretion is defined as the process of growth or increase, typically by the gradual accumulation of additional layers or matter. Formation of the Solar System Smaller particles collided with each other and formed larger particles, eventually reaching the size of a planetesimal, which is several kilometers in size. These planetesimal have their own gravitational pull, causing more collision, and growing even larger. Formation of the Solar System For planetesimals near the Sun, water evaporated, and gases were swept outside and only heavier materials solidified. These formed the terrestrial planets. Terrestrial planets are made up of rocks and metals, and their surface is either solid or liquid. Examples of terrestrial planets are; Mercury, Venus, Earth, and Mars. Formation of the Solar System Farther away from the Sun, the temperature was cooler. The number of rocks, metals, and hydrogen, which also became their core, allowed larger bodies to form, these led to the creation of the Jovian planets. Gas giants don’t have hard surfaces, they instead have swirling gases above a solid core. Examples of gas giants are; Jupiter, Saturn, Uranus, and Neptune. Subsystems of the Earth The Atmosphere Originating from the Greek words “atmo”, which means vapor, steam, or smoke, and “sphaira” which means ball. The atmosphere is a layer of gas and suspended solids extending from the Earth's surface up many thousands of miles, becoming increasingly thinner with distance but always held by the Earth's gravitational pull. The atmosphere is divided into several layers according to altitude. These are… The Atmosphere Exosphere is where the atmosphere merges with the outer space. Thermosphere is where auroras appear. Mesosphere is where meteors and other objects entering the Earth’s atmosphere start to burn. Stratosphere is where jets and airplanes fly. Troposphere is where clouds and most weather conditions can be found. The Biosphere Originating from the Greek words “bios”, which means life, and “sphaira” which means ball. It is made up of parts of the Earth where life exists. The Hydrosphere Originating from the Greek words “hydro”, which means water, and “sphaira” which means ball. It is made up of all the water in the planet; whether it is on the surface, underground, or on air. It could also be liquid, solid, or gas. The frozen part of the hydrosphere has its own name, cryosphere. Which originates from the Greek words “cryo”, which means ice, and “sphaira” which means ball. The Geosphere Originating from the Greek words “geo”, which means earth, and “sphaira” which means ball. It is made up of the solid portions of the Earth, which includes the crust and all the other layers of the Earth’s interior. The Geosphere Crust is the outermost and thinnest layer of the geosphere. Continental and oceanic crusts are its two types. The Geosphere Oxygen is the most abundant element in the Earth’s crust. The Geosphere The Mohorovicic discontinuity or simply “Moho” separates the crust from the mantle. Discontinuity is a word used to describe a surface at which seismic waves change velocity. The Geosphere It was first identified in 1909 by Andrija Mohorovicic, a Croatian geophysicist. The Geosphere The mantle is the layer of semi-solid rock in between the crust and core, it has an estimated size of 2900 km. The Geosphere The mantle has three parts; the outer mantle, transition zone, and lower mantle. The transition zone is another kind of discontinuity. The Geosphere Convection current happens in the mantle, which is responsible for the movement of tectonic plates. The Geosphere The Earth’s core is a sphere made up of iron-nickel alloy, found at the center of the Earth. The Earth’s core has two parts: the outer core and inner core. The Geosphere The outer core is mostly made up of molten iron, nickel, and silicon. It has an estimated size of 2200 km. The flow in the outer core is responsible for the Earth’s magnetic force. The Geosphere The inner core is made-up of solid iron- nickel alloy. It has an estimated size of 1220 km.