1º ESO

1. UNIT 3 & 4: THE
UNIVERSE, THE
SOLAR SYSTEM AND
THE EARTH

2. WHAT IS THE UNIVERSE LIKE?
 The Universe is all the matter, energy and space
that exists.
 The Universe is made up of galaxies which
contains stars and planetary systems.
 Galaxies are a vast of collection of stars, dust and
gases, held together by the gravitational attraction.
Our galaxy is the Milky Way.
 Stars are massive spherical bodies of gases. They
emit heat and light.
 Planets are spherical bodies which orbit some
stars. They do not emit light. Our planetary system
is the Solar System.(8 planets and the Sun)
 Natural satellites orbit some planets. The Earth’s
satellite is the Moon.
 Asteroids are rocky objetcs with irregular shape.

3. Galaxy The Milky Way Asteroid

4.  Galaxies appear in groups called galaxy clusters.
The Milky Way belongs to the Local Group galaxy
cluster.
The Milky Way over Utah.

5.  Different theories to explain the Universe:
 Geocentric theory: 2nd Century BC. Ptolomy
proposed that the Earth was the centre of the Universe.
 Heliocentric theory: In 1542 Copernicus proposed
that the Sun was at the centre of the Universe.
 In 1570 Lippershey invented the telescope, and
Galileo proved that the planets revolve around the
Sun.
Geocentric
Heliocentric

6. ACTIVITIES
1. Imagine an alien friend from another galaxy
wants to write to you. Write your galactic
addres.
2. Make a drawing of the heliocentric and
geocentric theories, label their components and
the person who proposed it.
3. Find ten words. M P L A N E T S
I G R L A A S A
L U A T S R P T
K N E L T T A E
Y S E N A H C L
W O H B R X E L
A T M S U N Y I
Y M O O N L G T
K E S W C P A E

7. HOW BIG IS THE UNIVERSE?
 The Big Bang theory says that the universe was once
in an extremely hot and dense state that expanded
rapidly 13.700 millions years ago.
 The Earth seems huge, but it’s small compared to the
Sun.
 The Sun is 1.300.000 times greater than the Earth.

8. WHAT MAKES UP THE SOLAR
SYSTEM?
 The Solar System was formed five thousand million years
ago from the gas and dust of a nebula.
 Our Solar System is made up of the Sun, eight planets
with their satellites, dwarf planets and small solar
system bodies.
 The Sun consists mainly of two gases: hydrogen and
helium.
 Planets revolve around the Sun in elliptical orbits.
Mercury, Venus, Earth and Mars are made up of rock.
Jupiter, Saturn, Uranus and Neptune are made up of
gases.
 Dwarf planets are smaller than planets and they orbit
the Sun. Pluto.
 Small solar system bodies are other celestial bodies which
orbit the Sun. They include asteroids, comets and
satellites.

10. WHICH ARE THE INNER PLANETS?
 The inner planets are the four planets closest to
the Sun: Mercury, Venus, the Earth and Mars.
 They are terrestrial or rocky planets. The crust
and mantle are made of rock. The core is
metallic.
 The Earth is the only planet that has life on it.
 In 2004, the robots Spirit and Opportunity
landed on Mars.

11.  The geosphere is the solid sphere of our planet.
 It’s divided into three layers:
The crust: is the surface of the Earth. It’s
between 5 and 70 km thick. It can be
continental crust and oceanic crust.
The mantle: is the thickest layer of hot rock.
Two parts: upper mantle and lower mantle.
The core: is the hottest layer. It’s made up of
iron and nickel. Two parts: Outer core and
inner core.
THE GEOSPHERE

12. LAYERS OF THE EARTH

13. PHASES OF THE MOON
 The Moon shows 4 different phases:
 New Moon: We cannot see the Moon.
 First Quarter: We can see the right side
illuminated.
 Full Moon: We see the whole Moon illuminated.
 Last Quarter: We can see the left side illuminated.

14. ECLIPSES
 An eclipse occurs when a celestial body hides
another temporarily. It can be partially or
completely.
 Lunar eclipse: It occurs when Earth blocks the
Sun's rays from the Moon.
 Solar eclipse: It occurs at New Moon when the
Moon passes between Earth and Sun.

15. Lunar eclipse

17. THE TIDES
 The tides are periodic
movements of the level of the
seas due to the attraction of
the Moon and the Sun.
 When the water level rises is
called high tide.
 When the water level goes
down is called low tide.

18. ACTIVITIES
1. What do we call the side of the Moon we cannot see?
2. Which has more influence on tides, the Moon or the
Sun?
3. Define:
a) Eclipse
b) Tide

19. ACTIVITIES
1. Make a drawing of the Earth’s spheres and label
them in English and Spanish.