Earth Science Chapter 1: Introduction to Earth Science Edward J. Tarbuck & Frederick K. Lutgens
Earth Science v Encompasses all sciences that seek to understand: Earth Earth's neighbors in space v Earth Science includes Geology - literally the study of Earth Geochemistry, Geophysics, Geobiology, Paleontology, etc Oceanography a study of the ocean
Earth Science v Earth Science includes: Meteorology - the study of the atmosphere and the processes that produce weather Astronomy - the study of the universe Many of these areas integrate other sciences like chemistry, physics, biology, as well as various branches of Earth Science.
Formation of Earth v Origin of Earth Most researchers believe that Earth and the other planets formed at essentially the same time and from the same material. Nebular hypothesis Solar system evolved from an enormous rotating cloud called the solar nebula Nebula was composed mostly of hydrogen and helium, with smaller amounts of heavier elements.
Formation of Earth v Origin of Earth Nebular hypothesis continued About 5 billion years ago the nebula began to contract Assumes a flat, disk shape with the protosun (pre- Sun) at the center Inner planets begin to form from metallic and rocky clumps Mercury, Venus, Earth & Mars Larger outer planets began forming from lighter materials and gases combined farther away from the center with a high percentage of ices Jupiter, Saturn, Uranus, & Neptune
Formation of Earth v Origin of Earth Nebular hypothesis continued High temps and weak fields of gravity characterized the inner planets could not hold onto lighter gases. Hydrogen and Helium whisked away toward the heavier planets by solar wind. Earth, Mars & Venus were able to retain some heavier gases including water vapor and carbon dioxide. Outer planets contain mostly H and He, but also high percentages of water, CO 2, ammonia, and methane in addition to rock and metal cores.
The Nebular hypothesis
Formation of Earth v Layers Form on Earth As Earth formed, the decay of radioactive elements and heat from high-velocity impacts caused the temperature to increase Iron and nickel began to sink toward the center Lighter rocky components floated outward, toward the surface Gaseous material escaped from Earth s interior to produce the primitive atmosphere
1.2 - A View of Earth v Earth s Major Spheres v Hydrosphere Ocean the most prominent feature of the hydrosphere Nearly 71% of Earth's surface About 97% of Earth's water Also includes fresh water found in streams, lakes, and glaciers, as well as that found underground
Earth's Spheres" v Atmosphere A life-sustaining, thin, tenuous blanket of air Over half of the mass lies below 5.6 kilometers (3.5 miles) Provides air we breathe, protects us from the sun s intense heat and radiation. The energy exchanges between space, the atmosphere, and Earth s surface produce weather and climate.
Earth's Spheres" v Geosphere Based on compositional differences, it consists of the crust, mantle, and core Divisions of the outer portion are based on how materials behave Lithosphere - rigid outer layer Divisions of Earth s surface - continents and ocean basins
Earth s layered structure
v Biosphere Earth's Spheres" Includes all life Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere v Interactions Our environment is characterized by the continuous interactions of air and rock, rock and water, and water and air.
v Plate Tectonics A View of Earth Two forces affecting Earth s surface: Destructive weathering and erosion working to wear away high points and flatten out the surface. Constructive mountain building & volcanism build up the surface and depend on Earth s internal heat for energy In the early 20 th Century a revolution began with the idea that the continents had moved!
A View of Earth v Plate Tectonics A new theory emerges Plate Tectonics! Provided geologists with a model to explain how earthquakes and volcanic eruptions occur and how continents move The lithosphere is broken up into several sections called plates that move slowly and continually driven by unequal distribution of internal heat. The movement of plates generates earthquakes, volcanic activity, and deforms large masses of land into mountains.
1.3 Representing Earth s Surface v Determining Location Latitude and Longitude are lines on a map used to determine location Latitude distance North or South of the equator. Longitude distance east or west of the prime meridian Divided the Earth into Hemispheres North, South, East and West.
Representing Earth s Surface v Maps and Mapping A map is flat, the Earth is round No matter what kind of map is made, some portion of the surface will always look too small, too big, or out of place. Mapmakers have found ways to limit the distortion of shape, size, distance, and direction. There are many different types of maps, such as the Mercator projection map (used by sailors), Robinson Projection, Conic Projection, & Gnomic Projection
Topographic Maps v Shape of the land Represents 3-D surface in 2-D Show elevation, water bodies, roads, government and public buildings, political boundaries, and place names. Important for geologists, hikers, campers and anyone else interested in the lay of the land Contour lines indicate elevation, every position along a line is the same elevation Contour interval difference in elevation between 2 adjacent lines.
Topographic Maps v Scale A map represents a certain amount of area on earth s surface. A certain distance on the map = a certain distance at the surface. 1:24,000 1 unit on map = 24,000 units on surface.
Topographic Maps v Geologic Maps Shows the type and age of the rocks that are exposed, or crop out, at the surface. Rock formations are assigned colors and sometimes a pattern.
Satellites & Information v Technology Technology Satellites and computers send and receive data, converted to images and accurate maps. Remote Sensing process of collecting data about Earth from a distance. Data is used to study rivers, pollution, oceans, fires, natural resources, etc
Satellites & Information v Technology Technology GPS Global Positioning Systems can provide maps in our cars to help us reach destinations. Consists of an instrument that receives signals to compute the user s lat and lon as well as speed, direction, and elevation. Used by ships and airplanes for navigation. Used by scientists to track wildlife, study earthquakes, measure erosion, etc
1.4 - Earth System Science v Earth is a dynamic body with many separate but highly interacting parts or spheres v Earth system science studies Earth as a system composed of numerous parts, or subsystems v System - any size group of interacting parts that form a complex whole
Earth System Science v System Closed systems are self-contained (e.g. an automobile cooling system) Open systems - both energy and matter flow into and out of the system (e.g. a river system)
Earth System Science v Earth as a System The Earth System is powered by energy from two sources: The Sun drives external processes that occur in the atmosphere, hydrosphere and at the surface Earth s Interior heat generated by the decay of radioactive elements, powers internal processes that produce volcanoes, earthquakes and mountains. Parts are linked together so a change in one area can produce changes in any or all of the other parts.
The hydrologic cycle
Earth System Science v Earth as a System Humans are a part of the Earth System. Our actions produce changes in all of the other parts of the Earth System. v People & The Environment Environment refers to everything that surrounds and influences an organism. Nonliving factors water, air, soil, rock, temperature, humidity, and sunlight, etc Living (biological) factors
People and the Environment v Environment Physical environment encompasses water, air, soil, and rock Term environmental is usually reserved for those aspects that focus on the relationships between people and the natural environment
People and the Environment v Resources Important focus of Earth Science Include water and soil, metallic and nonmetallic minerals, and energy forms the foundation of modern civilization Renewable resources can be replenished over relatively short time spans. Nonrenewable resources are so slow to form that it takes millions of years for significant deposits to form Limited quantities
People and the Environment v Population Population of the planet is growing rapidly Rate of mineral and energy usage has climbed more rapidly than the overall growth of population v Environmental problems Local, regional, and global
Growth of world population
People and the Environment v Environmental problems Human-induced and accentuated Urban air pollution Acid rain Ozone depletion Global warming
People and the Environment v Environmental problems Natural hazards continued Earthquakes Landslides Floods Hurricanes World population pressures An understanding of Earth is essential for locating and recovering resources, dealing with the human impact on the environment and minimizing the effects of natural hazards
People and the Environment v Knowledge about the earth and how it works is necessary for our survival and well being. v It is the only suitable habitat we have, and its resources are limited!
1.5 What is Scientific Inquiry? v Science assumes the natural world is Consistent Predictable v Goal of science To discover patterns in nature To use the knowledge to predict
Scientific Inquiry v An idea can become a Hypothesis (tentative or untested explanation) Theory (tested and confirmed hypothesis) Paradigm (a theory that explains a large number of interrelated aspects of the natural world) v Scientific method Gather facts through observation and measurement Formulate hypotheses and theories
Scientific Inquiry v Scientific knowledge is gained through (1) Following systematic steps Collecting facts Developing a hypothesis Conduct experiments Reexamine the hypothesis and accept, modify, or reject (2) Theories that withstand examination (3) Totally unexpected occurrences
Scientific Inquiry v Science is not a great many things, but in the end they all return to this: Science is the acceptance of what works and the rejection of what does not. Jacob Bronowski (mathematician) Thus, science is ever-changing!
End of Chapter 1