Origin of the Universe
• Great explosion (BIG
BANG)
• 10.000 / 18.000 years
ago

Composition of the Universe
• Chemical elements • Energy in the
in the Universe Universe
• Gases : Hydrogen, • Light Energy
Helium • Heat energy
• Other elements: • Nuclear Energy
Oxygen, Silicon, • Magnetism
metals
• Electricity
• Compounds:Water,
Carbon dioxide

Composition of the Universe
• The Universe is made
up of galaxies

Our galaxy : Milky Way
• Our galaxy, Milky
Way, is a spiral galaxy

Star systems
• Star systems are • Solar system is made
made up of: up of:
• Central star • The Sun
• Stars grouped in • Ursa Major (The
constellations Plough); Ursa Minor,
• Planets and satellites Orion, Zodiac .
• Asteroids or • Eight planets
metreorites

Stars and constellations
• Stars are huge balls of • The Sun
gas that give out light
and heat energy
• The stars are fixed in the
sky
• The stars are bright (the
closer, the brighter)
• Stars colour
– Blue stars are colder than
red stars.
– Yellow stars (Sun) have
medium heat

Constellations
• Constellations are
groups of stars with
special patterns

8 planets in the Solar system
• Planets haven’t light and
energy, they reflect light
from the Sun
• Heliocentric theory:
Planets go around the
Sun.
Copernicus, XVI century
• Geocentric theory ,wrong:
the Sun and planets go
around the Earth

Relative size of the Sun and planets

Distances in the Universe
• The Universe is very very big (infinite)
• Telescope. Galileo XVII century.
• Actual telescope : Hubble telescope
• Light year : Distance that the light travels in one year
with the speed 300.000 Km/s

Movements of the Earth and Moon
• Rotation movement • The Moon is the satellite
– Around its axis of the Earth
– 24 hours • Rotation movement
– Consequence : day and – Around its axis
night
– 28 days
• Revolution movement • Revolution movement
– Around the Sun
– Around the Earth
– 365 + ¼ days:
– 28 days
– Consequence :
– Consequence : Phases of
– Year / Leap year the Moon

Phases of the Moon
• The Moon doesn’t give out
light, but reflects the Sun’s
light
• Rotation and revolution
movement of the Moon have
the same period : 28 days.
• So, we always see the same
face of the Moon in different
phases:
– New Moon
– Waxing Moon (First Quarter)
– Full Moon
– Waning Moon (Last Quarter)

Gravity pull force
• Gravity is the force of attraction of heavenly bodies in the Universe
• Everything in the Universe is attracted, by the force of gravity, to
everything else.
• The Earth and Moon are attracted by gravity.
• Gravity’s Moon causes tides on the Earth
• Tides =Mareas. High tide marea alta. Low tide marea baja
• Gravity of the Earth causes revolution movement of the Moon
around the Earth.
• Gravity depends on the size of heavenly bodies (big planets have
high gravity)
• Gravity depends on the distance between heavenly bodies
(The Earth and Neptune are very far, so there is a weak attraction
between them)

Seasons of the year
• Cause : The axis of the Earth is tilted
• Consequence :The seasons of the year.
– When the Northern hemisphere tilts towards the Sun, it gets
more light and heat
– And is summer in the Northern hemisphere

Seasons of the year
• Cause :The Earth’s axis of rotation is tilted with respect
to the Sun’s radiation.
• Consequence: The seasons of the year.
– The tilted Hemisphere to the Sun receives more light and heat .
– So, it will be summer in this Hemisphere

Eclipses
• Lunar eclipse
– The Earth is between the
Sun and the Moon
– Total and partial eclipse
• Solar eclipse
– The Moon is between the
Sun and the Earth
– Total and partial eclipse