UNIT 3 & 4: THEUNIVERSE, THESOLAR SYSTEM ANDTHE EARTH
WHAT IS THE UNIVERSE LIKE? The Universe is all the matter, energy and spacethat exists. The Universe is made up of galaxies whichcontains stars and planetary systems. Galaxies are a vast of collection of stars, dust andgases, held together by the gravitational attraction.Our galaxy is the Milky Way. Stars are massive spherical bodies of gases. Theyemit heat and light. Planets are spherical bodies which orbit somestars. They do not emit light. Our planetary systemis the Solar System.(8 planets and the Sun) Natural satellites orbit some planets. The Earth’ssatellite is the Moon. Asteroids are rocky objetcs with irregular shape.
Galaxies appear in groups called galaxy clusters.The Milky Way belongs to the Local Group galaxycluster.The Milky Way over Utah.
Different theories to explain the Universe: Geocentric theory: 2nd Century BC. Ptolomyproposed that the Earth was the centre of the Universe. Heliocentric theory: In 1542 Copernicus proposedthat the Sun was at the centre of the Universe. In 1570 Lippershey invented the telescope, andGalileo proved that the planets revolve around theSun.GeocentricHeliocentric
ACTIVITIES1. Imagine an alien friend from another galaxywants to write to you. Write your galacticaddres.2. Make a drawing of the heliocentric andgeocentric theories, label their components andthe person who proposed it.3. Find ten words. M P L A N E T SI G R L A A S AL U A T S R P TK N E L T T A EY S E N A H C LW O H B R X E LA T M S U N Y IY M O O N L G TK E S W C P A E
HOW BIG IS THE UNIVERSE? The Big Bang theory says that the universe was oncein an extremely hot and dense state that expandedrapidly 13.700 millions years ago. The Earth seems huge, but it’s small compared to theSun. The Sun is 1.300.000 times greater than the Earth.
WHAT MAKES UP THE SOLARSYSTEM? The Solar System was formed five thousand million yearsago from the gas and dust of a nebula. Our Solar System is made up of the Sun, eight planetswith their satellites, dwarf planets and small solarsystem bodies. The Sun consists mainly of two gases: hydrogen andhelium. 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 ofgases. Dwarf planets are smaller than planets and they orbitthe Sun. Pluto. Small solar system bodies are other celestial bodies whichorbit the Sun. They include asteroids, comets andsatellites.
WHICH ARE THE INNER PLANETS? The inner planets are the four planets closest tothe Sun: Mercury, Venus, the Earth and Mars. They are terrestrial or rocky planets. The crustand mantle are made of rock. The core ismetallic. The Earth is the only planet that has life on it. In 2004, the robots Spirit and Opportunitylanded on Mars.
The geosphere is the solid sphere of our planet. It’s divided into three layers:The crust: is the surface of the Earth. It’sbetween 5 and 70 km thick. It can becontinental 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 ofiron and nickel. Two parts: Outer core andinner core.THE GEOSPHERE
PHASES OF THE MOON The Moon shows 4 different phases: New Moon: We cannot see the Moon. First Quarter: We can see the right sideilluminated. Full Moon: We see the whole Moon illuminated. Last Quarter: We can see the left side illuminated.
ECLIPSES An eclipse occurs when a celestial body hidesanother temporarily. It can be partially orcompletely. Lunar eclipse: It occurs when Earth blocks theSuns rays from the Moon. Solar eclipse: It occurs at New Moon when theMoon passes between Earth and Sun.
THE TIDES The tides are periodicmovements of the level of theseas due to the attraction ofthe Moon and the Sun. When the water level rises iscalled high tide. When the water level goesdown is called low tide.
ACTIVITIES1. What do we call the side of the Moon we cannot see?2. Which has more influence on tides, the Moon or theSun?3. Define:a) Eclipseb) Tide
ACTIVITIES1. Make a drawing of the Earth’s spheres and labelthem in English and Spanish.