The Earth in the Univers e
Geology
The Earth in the Universe
The Earth in the Universe
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• The origin of the Universe
• The position of the Earth in the Universe
• Distances in the Universe
• Galaxies
• The Milky Way
• Stars: The Sun
• The Solar System
• The movements of the planets
• Planets in the Solar System
• The Earth’s revolution
• The Earth’s rotation
• The importance of the Earth’s movements for living things
• The Sun, Earth and Moon
The Earth in the Universe
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The origin of the Universe
The Earth in the Universe
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The Universe or Cosmos is defined as everything that exists.
The Earth in the Universe
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The position of the Earth in the Universe
The Earth in the Universe
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Geocentric model Heliocentric model
• The Earth is spherical and is the centre of the Universe.
• The Sun, the Moon and the planets revolve in concentric circles around the Earth.
• The stars are fixed on a dome that also revolves around the Earth
• The Sun does not move and is in the centre of the Universe.
• All the planets revolve around the Sun in concentric circles.
• The Earth rotates on its axis and the Moon revolves around the Earth.
• The stars are fixed on a dome that does not move.
Sun
Mercury
Venus Earth Moon
Mars
Jupiter
Saturn
Sun
Venus
Earth
Moon
Mars
Jupiter
Saturn
Mercury
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Distances in the Universe
The Earth in the Universe
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Light year
A light year is equivalent to the distance travelled by light in one year. Light travels at a speed of 300000 km per second.
1 year x 365 days x 24 hours x 3 600 segundos x 300 000 km/s = 9.5 billion km
Parsec
A parsec (pc) is equivalent to 3.26 light years.
La unidad astronómica
An astronomical unit (AU) is the distance between the Earth and the Sun.
1 UA = 150 million km
The Earth in the Universe
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Galaxies
The Earth in the Universe
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Galaxies are huge group of stars, nebulae and interstellar dust and gas held together by the force of gravity.
Nebulae are huge clouds of gas. They are formed by concentrations of hydrogen and helium as well as interstellar dust.
eliptical spiral barred spiral irregular
The Earth in the Universe
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The Milky Way
The Earth in the Universe
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The Milky Way is a spiral galaxy, located in a galaxy cluster called the Local Group.
nucleus disk halo
The Earth in the Universe
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Stars: The Sun
The Earth in the Universe
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Stars are large spheres of gas spheres made mostly of hydrogen and helium. Stars release energy in the form of light and heat.
The Sun is a medium-sized yellow star with a surface temperature of 5500 ºC.
photosphere
core
Type Temperature (ºC) Colour Example
O >30 000 Violet-blue Naos
B 10 000- 30 000 Blue Rigel
A 7 500- 10 000 White Vega
F 6 000- 7 500 White-yellow Protion
G 5 000- 6 000 Yellow Sun
K 3 500- 5 000 Orange Arcturus
M 2 000- 3 000 Red Betelgeuse
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The Solar System
The Earth in the Universe
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The Solar System consists of the Sun and the celestial bodies that orbit it.
Composition:
• Planets • Dwarf planets • Satellites • Asteroid belt • Comets
Pluto (dwarf planet)
Saturn
Uranus Neptune
Jupiter
Mars
Earth
Venus Sun
Mercury
path of Halley’s comet
asteroid belt
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The movements of the planets
The Earth in the Universe
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Revolution (year)
Rotation (day)
Pluto (dwarf planet)
Earth Venus
Sun
Neptune
Mercury
Earth 23.5⁰
Venus 177⁰
Mercury 0.1⁰
Pluto (dwarf planet) 120⁰ Saturn
27⁰
Uranus 98⁰
Neptune 30⁰
Jupiter 3⁰
Mars 25⁰
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Planets in the Solar System
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Inner planets
The inner planets are small, have very little or no atmosphere and have a rocky surface.
Outer planets
The outer planets are very large and have a gaseous atmosphere. They are surrounded by rings and their surface is in a gaseous or liquid state.
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The Earth’s revolution
The Earth in the Universe
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The Earth moves around the sun in an elliptical orbit. It takes the Earth 365 days, 5 hours and 49 minutes to complete one revolution.
perpendicular to the ecliptic plane 23.5⁰
rotation axis
ecliptic plane
revolution
winter
summer Sun summer
winter
smaller angle = bigger area
bigger angle = smaller area
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The Earth’s rotation
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The Earth takes 23 hours and 56 minutes to complete one rotation on its axis. Rotation causes day and night.
The Earth in the Universe
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The importance of the Earth’s movements for living things
The Earth in the Universe
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Many trees lose their leaves in autumn, when they detect a decrease in the hours of daylight.
Trees then sprout new leaves in spring, with the increase in the hours of daylight.
Flowering and forming of fruits also depend on temperatures and hours of daylight and darkness. Not all plants flower and form fruit in the same season.
The mating and breeding seasons of many animals start when the days get shorter and temperatures lower.
Some birds migrate at certain times of the year
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The Sun, Earth and Moon
The Earth in the Universe
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Phases of the Moon
first quarter
last quarter
Eclipses
solar eclipse lunar eclipse
Tides
full moon new moon
Earth
Moon
ecliptic plane
5.15⁰
spring tides
neap tides
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