Earth Science: Exploring the Solar System and Physical Environment
UGRC 144
Science and Technology in Our
Lives/Geohazards
Session 2 – THE EARTH
Lecturer: Dr. Patrick Asamoah Sakyi
Department of Earth Science, UG
Contact Information: pasakyi@ug.edu.gh
Session Overview
•
The Earth is a huge sphere covered with
water, rock and soil, and is surrounded by air.
•
Earth is part of the Solar System. It is one of
eight planets that travel through space around
the sun.
•
The solar system consists of a star called the
SUN and all bodies that orbit the Sun.
2
Session Outline
The key topics to be covered in the session are as
follows:
•
The Solar System
•
The Earth’s Physical Environment
•
The structure of the earth’s interior and its
relationships to earthquakes.
3
Reading List
•
Read Chapter 1 of Environmental Geology 4
th
Edition – by Carla W Montgomery (1995)
•
Read Unit 1, Section 2 of UGRC 140 II Geohazards –
Institute of Continuing and Distance Education
4
The SOLAR SYSTEM
Topic One
5
The Solar System
•
The Earth
is a huge sphere
covered with water, rock and soil,
and is surrounded by air. Earth is
part of the Solar System. It is one
of eight planets that travel through
space around the sun.
•
The solar system consists of a star
called the SUN and all bodies that
orbit the Sun (Fig. 1.1).
•
The sun is one of billions of stars
that make up a galaxy called the
Milky Way, which is also one of
billions of galaxies that make up
the Universe
6
Figure 1.1: The Solar System
The Earth
(cont’d)
■
The earth ranks fifth in size among the planets and is
about 150 million km from the sun. It is the only planet
with an atmosphere that can support plant and animal
life.
■
In space, Earth has three main movements. It
rotates
or spins on its axis and this
rotation causes day and
night.
■
It revolves round or orbits the
sun.
■
The
Earth also moves through the Milky Way with the
rest of the solar system. The orbit of the earth round
the sun covers a distance of 958,000,000 km.
■
The
earth has one satellite, the moon, of diameter
3476 km.
7
The Earth's Physical Environment
Topic Two
8
The Earth’s Physical Environment
•
The earth is a dynamic planet, which has been
changing throughout geologic time. It consists of a
solid sphere surrounded by surface fluids and a
magnetic force field.
•
The Earth’s physical environment is traditionally
divided into three major parts,
–
the Atmosphere,
–
Hydrosphere
–
Solid Earth’s Surface (Land). temperature.
9
The Earth’s Physical Environment
•
The atmosphere is a thin gaseous-layer made
up of air, which surrounds the earth, extending
up to 1,600 km above the surface. Air is made
up of nitrogen, oxygen, argon and other gases.
•
Variations in the behaviour of the atmosphere
produce weather events and climate patterns.
The atmosphere influences the
10
Earth’s Physical Environment
(cont’d)
•
All bodies of water and ice, as
well as water vapour in the
atmosphere make up the earth’s
hydrosphere (Fig, 1.2).
•
The dominant feature of the
hydrosphere is the Oceans.
Oceans blanket nearly 71
percent of Earth’s surface and
account for more than 97
percent of Earth’s water.
•
The hydrosphere also includes
the fresh water found
underground, in streams, lakes,
and glaciers.
11
Figure 1.2: Composition of the hydrosphere
The Earth’s Physical Environment
(cont’d)
•
The largest bodies of land are
called continents.
•
Continents are scattered
masses on a planet that is
largely covered by water, but
they are the most prominent of
earth’s features.
•
Most mountain chains form
along the margins of the
continents
•
Rocks comprising mountains
provide striking visual evidence
of enormous compressional
forces that have deformed
large sections of the crust (Fig.
1.3).
12
Figure 1.3: Folded Rocks in a Mountain Belt
The Earth’s Physical Environment
(cont’d)
•
Other landforms and geologic features that exist on
the earth’s landmasses include deserts, rivers,
plateaus and volcanoes
•
Also forming an integral part of earth, is the
biosphere, which is totality of all plants and animal
life on our planet.
13
The Earth’s Interior
Topic Three
14
The Earth’s Interior
•
E
a
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e
.
15
The Earth’s Interior Layers Defined by
Composition
•
C
r
u
s
t
–
Thin, rocky outer layer of the earth
–
It varies in thickness
–
Roughly 7 km in oceanic regions
–
Continental crust averages 8–40 km, but
exceeds 70 km in mountainous regions
16
The Earth’s Interior Layers Defined by
Composition
•
C
o
n
t
i
n
e
n
t
a
l
c
r
u
s
t
–
Upper continental crust composed of
lighter, granitic rocks,
–
Lower continental crust is more similar to
basalt,
–
Average density is about 2.7 g/cm
3
–
It is up to 4 billion years old
17
The Earth’s Interior Layers Defined by
Composition
•
O
c
e
a
n
i
c
c
r
u
s
t
–
It is basaltic composition,
–
Density about 3.0 g/cm
3
–
Younger (180 million years or less) than
the continental crust
18
The Earth’s Interior Layers Defined by
Composition
•
M
a
n
t
l
e
–
It is b
elow the crust to a depth of 2900 kilometers
–
Composition of the uppermost mantle is the
igneous rock peridotite.
–
Some of the lava that reaches the Earth’s surface
comes from asthenosphere within.
19
The Earth’s Interior Layers Defined by
Physical properties
•
U
p
p
e
r
M
a
n
t
l
e
•
L
i
t
h
o
s
p
h
e
r
e
–
Is made up of the crust and uppermost mantle (about
100 km thick)
–
Cool, rigid, solid
•
A
s
t
h
e
n
o
s
p
h
e
r
e
–
Upper mantle
–
Lies beneath the lithosphere to a depth of about 660
kilometers,
–
It is soft, hot and weak layer that is easily deformed
20
The Earth’s Interior Layers Defined by
Physical properties
•
C
o
r
e
–
The core is below the mantle,
–
It is sphere with a radius of 3486
kilometers,
–
It is composed of an iron-nickel alloy,
–
Average density of nearly 11 g/cm
3
21
The Earth’s Interior Layers Defined by
Physical properties
•
I
n
n
e
r
C
o
r
e
–
Sphere with a radius of 1216 km
–
It behaves like a solid
•
O
u
t
e
r
C
o
r
e
–
Liquid layer
–
2270 km thick
–
Convective flow of metallic iron within
generates Earth’s magnetic field
22
Earth’s Layered Structure
23
The Theory of Plate Tectonics
•
The theory of plate tectonics, describes the
mobile earth, and holds that the outer, rigid layer
of Earth consists of about a dozen major segments
called Plates.
•
Plates form the Earth’s rigid outer shell called the
lithosphere. The lithosphere overlies a zone of
weaker and hotter material known as the
Asthenosphere, and the former moves over the
latter.
24
The Theory of Plate Tectonics
25
The Theory of Plate Tectonics
26
Summary
•
In this session we discussed the earth in space as one of the planets within
the solar systems. We observed that the earth’s physical environment is
traditionally divided into three major parts, the atmosphere, hydrosphere and
solid earth’s surface (land).
•
Materials within the interior of the earth are segregated and concentrated
according to density. The major units of the solid earth are; a solid inner core,
surrounded by a liquid outer core, a solid mantle and a thin solid crust.
•
The lithosphere is a 100 m thick outer layer of the earth composed of
relatively cool, rigid rocks, situated above the asthenosphere- a hot, weak
zone below.
•
Gravity and magnetism are the two major force fields that influence the
earth. The scientific theory, which describes the mobile earth, is the theory of
plate tectonics. According to this theory, most earthquakes, volcanisms and
mountain building occur along plate boundary.
27
END
28
Delve into the realm of Earth science with Dr. Patrick Asamoah Sakyi to explore topics like the Solar System, Earth's physical environment, and the structure of the Earth's interior. Gain insights into our planet's place in the universe and its dynamic nature throughout geological time.
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Presentation Transcript
Lecturer: Dr. Patrick Asamoah Sakyi Department of Earth Science, UG Contact Information: pasakyi@ug.edu.gh College of Education School of Continuing and Distance Education 2014/2015 2016/2017
Session Overview The Earth is a huge sphere covered with water, rock and soil, and is surrounded by air. Earth is part of the Solar System. It is one of eight planets that travel through space around the sun. The solar system consists of a star called the SUN and all bodies that orbit the Sun. 2
Session Outline The key topics to be covered in the session are as follows: The Solar System The Earth s Physical Environment The structure of the earth s interior and its relationships to earthquakes. 3
Reading List Read Chapter 1 of Environmental Geology 4th Edition by Carla W Montgomery (1995) Read Unit 1, Section 2 of UGRC 140 II Geohazards Institute of Continuing and Distance Education 4
Topic One The SOLAR SYSTEM 5
The Solar System The Earth is a huge sphere covered with water, rock and soil, and is surrounded by air. Earth is part of the Solar System. It is one of eight planets that travel through space around the sun. The solar system consists of a star called the SUN and all bodies that orbit the Sun (Fig. 1.1). The sun is one of billions of stars that make up a galaxy called the Milky Way, which is also one of billions of galaxies that make up the Universe Figure 1.1: The Solar System 6
The Earth (contd) The earth ranks fifth in size among the planets and is about 150 million km from the sun. It is the only planet with an atmosphere that can support plant and animal life. In space, Earth has three main movements. It rotates or spins on its axis and this rotation causes day and night. It revolves round or orbits the sun. The Earth also moves through the Milky Way with the rest of the solar system. The orbit of the earth round the sun covers a distance of 958,000,000 km. The earth has one satellite, the moon, of diameter 3476 km. 7
Topic Two The Earth's Physical Environment 8
The Earths Physical Environment The earth is a dynamic planet, which has been changing throughout geologic time. It consists of a solid sphere surrounded by surface fluids and a magnetic force field. The Earth s physical environment is traditionally divided into three major parts, the Atmosphere, Hydrosphere Solid Earth s Surface (Land). temperature. 9
The Earths Physical Environment The atmosphere is a thin gaseous-layer made up of air, which surrounds the earth, extending up to 1,600 km above the surface. Air is made up of nitrogen, oxygen, argon and other gases. Variations in the behaviour of the atmosphere produce weather events and climate patterns. The atmosphere influences the 10
Earths Physical Environment (contd) All bodies of water and ice, as well as water vapour in the atmosphere make up the earth s hydrosphere (Fig, 1.2). The dominant feature of the hydrosphere is the Oceans. Oceans blanket nearly 71 percent of Earth s surface and account for more than 97 percent of Earth s water. The hydrosphere also includes the fresh water found underground, in streams, lakes, and glaciers. Figure 1.2: Composition of the hydrosphere 11
The Earths Physical Environment (cont d) The largest bodies of land are called continents. Continents are scattered masses on a planet that is largely covered by water, but they are the most prominent of earth s features. Most mountain chains form along the margins of the continents Figure 1.3: Folded Rocks in a Mountain Belt Rocks comprising mountains provide striking visual evidence of enormous compressional forces that have deformed large sections of the crust (Fig. 1.3). 12
The Earths Physical Environment (cont d) Other landforms and geologic features that exist on the earth s landmasses include deserts, rivers, plateaus and volcanoes Also forming an integral part of earth, is the biosphere, which is totality of all plants and animal life on our planet. 13
Topic Three The Earth s Interior 14
The Earths Interior Earth s interior consists of three major zones defined by their chemical composition the crust, mantle, and core. 15
The Earths Interior Layers Defined by Composition Crust Thin, rocky outer layer of the earth It varies in thickness Roughly 7 km in oceanic regions Continental crust averages 8 40 km, but exceeds 70 km in mountainous regions 16
The Earths Interior Layers Defined by Composition Continental crust Upper continental crust composed of lighter, granitic rocks, Lower continental crust is more similar to basalt, Average density is about 2.7 g/cm3 It is up to 4 billion years old 17
The Earths Interior Layers Defined by Composition Oceanic crust It is basaltic composition, Density about 3.0 g/cm3 Younger (180 million years or less) than the continental crust 18
The Earths Interior Layers Defined by Composition Mantle It is below the crust to a depth of 2900 kilometers Composition of the uppermost mantle is the igneous rock peridotite. Some of the lava that reaches the Earth s surface comes from asthenosphere within. 19
The Earths Interior Layers Defined by Physical properties Upper Mantle Lithosphere Is made up of the crust and uppermost mantle (about 100 km thick) Cool, rigid, solid Asthenosphere Upper mantle Lies beneath the lithosphere to a depth of about 660 kilometers, It is soft, hot and weak layer that is easily deformed 20
The Earths Interior Layers Defined by Physical properties Core The core is below the mantle, It is sphere with a radius of 3486 kilometers, It is composed of an iron-nickel alloy, Average density of nearly 11 g/cm3 21
The Earths Interior Layers Defined by Physical properties Inner Core Sphere with a radius of 1216 km It behaves like a solid Outer Core Liquid layer 2270 km thick Convective flow of metallic iron within generates Earth s magnetic field 22
The Theory of Plate Tectonics The theory of plate tectonics, describes the mobile earth, and holds that the outer, rigid layer of Earth consists of about a dozen major segments called Plates. Plates form the Earth s rigid outer shell called the lithosphere. The lithosphere overlies a zone of weaker and hotter material known as the Asthenosphere, and the former moves over the latter. 24
Summary In this session we discussed the earth in space as one of the planets within the solar systems. We observed that the earth s physical environment is traditionally divided into three major parts, the atmosphere, hydrosphere and solid earth s surface (land). Materials within the interior of the earth are segregated and concentrated according to density. The major units of the solid earth are; a solid inner core, surrounded by a liquid outer core, a solid mantle and a thin solid crust. The lithosphere is a 100 m thick outer layer of the earth composed of relatively cool, rigid rocks, situated above the asthenosphere- a hot, weak zone below. Gravity and magnetism are the two major force fields that influence the earth. The scientific theory, which describes the mobile earth, is the theory of plate tectonics. According to this theory, most earthquakes, volcanisms and mountain building occur along plate boundary.27
END 28
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