Origin of the Universe

• Great explosion (BIG BANG)

• 10.000 / 18.000 years ago

Composition of the Universe

• Chemical elements in the Universe

• Gases : Hydrogen, Helium• Other elements: Oxygen, Silicon,

metals• Compounds:Water, Carbon

dioxide

• Energy in the Universe• Light Energy• Heat energy• Nuclear Energy• Magnetism• Electricity

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 made up of:• Central star• Stars grouped in constellations• Planets and satellites• Asteroids or metreorites

• Solar system is made up of:• The Sun• Ursa Major (The Plough); Ursa Minor,

Orion, Zodiac .• Eight planets

Stars and constellations

• Stars are huge balls of 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

• The Sun

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

– Around its axis– 24 hours– Consequence : day and night

• Revolution movement– Around the Sun– 365 + ¼ days: – Consequence :– Year / Leap year

• The Moon is the satellite of the Earth• Rotation movement

– Around its axis– 28 days

• Revolution movement– Around the Earth– 28 days– Consequence : Phases of 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