The Earth in the Universe - IES Las Encinas · The Earth in the Universe © Oxford University Press...

The Earth in the Univers e

Geology

The Earth in the Universe


© Oxford University Press España, S. A. Geology 2

• 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 origin of the Universe



The Universe or Cosmos is defined as everything that exists.



The position of the Earth in the Universe



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



Distances in the Universe



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



Galaxies



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 Milky Way



The Milky Way is a spiral galaxy, located in a galaxy cluster called the Local Group.

nucleus disk halo



Stars: The Sun



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



The Solar System



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



The movements of the planets



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



Planets in the Solar System



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.



The Earth’s revolution



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



The Earth’s rotation



The Earth takes 23 hours and 56 minutes to complete one rotation on its axis. Rotation causes day and night.



The importance of the Earth’s movements for living things



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



The Sun, Earth and Moon



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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