UNIT 1: EARTH AND THE SOLAR SYSTEM.

UNIT 1: EARTH AND THE SOLAR SYSTEM. 1) A BRIEF HISTORY Theories of the Universe In the second century BC, the astronomer Ptolemy proposed that the Earth was the centre of the Universe, and that the Sun, Moon and planets orbited the Earth. This was known as the Geocentric theory, or the Ptolemaic System. However, in 1542, Nicolas Copernicus proposed that the Sun was at the centre of the Universe. When Galilieo Galilei invented the telescope in 1610, he could prove the Heliocentric theory (or Copernican System): the planets and stars revolve around the Sun. Answer the questions about the text. a) For how many centuries was the Geocentric theory used in astronomy? b) What did this theory suggest? c) What was Copernicus theory? d) Who invented the telescope? 1

2) OUR SOLAR SYSTEM What is the solar system? Our solar system consists of: - One central star, the Sun. - Eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and - Neptune. - More than 140 moons. - Millions of rocky asteroids. - Billions of icy comets. Other objects in the solar system COMETS AND ASTEROIDS STAR INFO CARD Name: THE SUN. Age: About 4.5 billion years. Location: At the centre of our solar system. Average distance from Earth: 149,600,000 km. Diameter: 1,390,000 kilometres. Mass: 1.99 x 1030 kg. Distinguishing features: The Sun, an ordinary star, contains more than 99.8% of the total mass of our solar system. PLANET INFO CARD Name: MERCURY. Avg. Distance from The Sun: 58,340,000 km. Diameter: 4880 Kilometres. Mass: 3.30 x1023 kg. Orbital period around the Sun: 0.24 Earth years (88 Earth days). Number of moons: 0. Distinguishing features: Temperature variations on Mercury are the most extreme in the solar system ranking from 170º C to 430º C. 2

PLANET INFO CARD Name: VENUS. Avg. Distance from The Sun: 108,200,000 km. Diameter: 12,100 km. Mass: 4.869 x 1024 kg. Orbital period around the Sun: 0.616 Earth years (225 Earth days). Number of moons: 0. Distinguishing features: Thick clouds containing sulfuric acid hide the rocky surface. PLANET INFO CARD Name: EARTH. Avg. Distance from The Sun: 149,600,000 km. Diameter: 12,760 km. Mass: 5.972 x 1024 kg. Orbital period around the Sun: 1 year (365 days) Number of moons: 1. Distinguishing features: Earth is the only planet to have liquid water on its surface. PLANET INFO CARD Name: MARS. Avg. Distance from The Sun: 227,900,000 km. Diameter: 6794 km. Mass: 6.4219 x 1023 kg. Orbital period around the Sun: 1.88 Earth years (687 Earth days). Number of moons: Mars has two moons: Deimos and Phobos. Distinguishing features: Known as the Red Planet, Mars has a very thin atmosphere. PLANET INFO CARD Name: JUPITER. Avg. Distance from The Sun: 778,300,000 km. Diameter: 143,000 km. Mass: 1.900 x 1027 kg. Orbital period around the Sun: 11.86 Earth years (4330 Earth days). Number of moons: Júpiter has more than 60 moons. The most important moon is Ganymede. Distinguishing features: Ganymede is the largest moon in our solar system (larger than even the planet Mercury). 3

PLANET INFO CARD Name: SATURN. Avg. Distance from The Sun: 1,429,000,000 km Diameter: 120,500 km. Mass: 5.69 x 1026 kg. Orbital period around the Sun: 29.46 Earth years (10,750 Earth days). Number of moons: Saturn has more than 50 moons. Distinguishing features: Saturn s most distinctive feature is the thousand of rings that orbit the planet. PLANET INFO CARD Name: URANUS. Avg. Distance from The Sun: 2,871,000,000 km Diameter: 51,120 km. Mass: 8.683 x 1025 kg. Orbital period around the Sun: 84 Earth years (30,660 Earth days). Number of moons: Uranus has more than 20 moons. Distinguishing features: The blue-green colour of the planet is due to methane in the atmosphere. PLANET INFO CARD Name: NEPTUNE. Avg. Distance from The Sun: 4,504,000,000 km Diameter: 49,530 km. Mass: 1.0247 x 1026 kg. Orbital period around the Sun: 164.8 Earth years (60,150 Earth days). Number of moons: Neptune has more than 10 moons.its the largest moon, Triton, is almost as large as Earth s moon. Distinguishing features: Neptune is smaller in diameter than Uranus, but larger in mass. 4

PLANET INFO CARD Name: PLUTO. Avg. Distance from The Sun: 5,914,000,000 km Diameter: 2340 km. Mass: 1.27 x 1022 kg. Orbital period around the Sun: 247.7 Earth years (90,410 Earth days). Number of moons: Pluto has three moons. Distinguishing features: Pluto was the smallest planet until August 2006, when the International Astronomical Union reclassified it as a dwarf planet. MOON INFO CARD Name: THE MOON. Age: About the same age as Earth. Avg. Distance from The Earth: 384,400 km. Diameter: 3476 km. Mass: 7.35 x 1022 kg. Orbital period around the Sun: 27 Earth days. Distinguishing features: The Moon has no atmosphere or magnetic field. A new mnemonic used to remember the planets in order is, MY VERY EDUCATED MOTHER JUST SERVED US NACHOS My Very Educated Mother Just Served Us Nachos Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune 5

Find the names of the eight planets hidden in this puzzle. V M E R C U R Y E C O N O G R J N A S T T U L U U R A N U S A P S T T I L O N I E N U T S E N T H T R A E K I E D S N M A R S R Find the words on the left in the puzzle and then match them to their definitions on the right. R B I O T H E D M I L K Y W A Y G G O S T A R S G B M O O N T U G A L A X Y H N U N I V E R S E A G P L A N E T Big Bang Earth Galaxy Milky Way Moon Planet Star Sun Universe Our star A lighted body An unlighted body Our world Our satellite Our planet The beginning A conjunct of stars Our galaxy Match each word to each definition. light year dwarf planets asteroids rotational axis orbit galaxy 1. They are smaller than planets and they orbit the Sun. 2. They are rocky objects which are irregular in shape. 3. It is the invisible line on which celestial objects spin or rotate. 4. It is the distance light travels in one year. 6

5. It is the curved path which a celestial object follows in its revolution around another celestial object. 6. It is a vast collection of stars, dust and gases, held together by gravitational attraction. Complete this chart. Planet Type Distance from the Sun (AU) Period of rotation Period of revolution Average surface temperature Mercury rocky 58,65 days Venus 0.72 224.6 days Earth 23 h 56 365.25 mins days Jupiter gaseo -150º C us Neptune 30,06-210º C Number of satellite s 0 1 Use your chart to complete these questions. Which planet 1. has the most satellites? 2. has the shortest period of rotation? 3. has the longest period of revolution? 4. is the greatest distance from the sun? 5. is the hottest? 6. rotates faster, Venus or Neptune? 7. Which planets are closer to the Sun, the rocky planets or the gaseous planets? 7

Now answer these questions. 1. Which galaxy does our Solar System belong to? 2. Which is the nearest star to our Solar System? 3. Which celestial bodies are made up of ice, dust and gas, and have bright tails? 4. What is the distance from the Earth to the Sun? 5. How fast does light travel in one second? Jigsaw chart. Work in pairs. Take turns to read and classify these sentences. Write each number in the correct category. 1. They are spherical bodies which orbit the Sun. 2. They are vast collection of stars, dust and gases. 3. They are imaginary patterns of bright stars. GALAXIES 4. There are eight of them. CONSTELLATIONS 5. They contain thousands of millions of stars. 6. Ours is called The Milky Way. 7. They are massive spherical bodies of gases. STARS 8. They all move in elliptical orbits. 9. They emit light and heat. 10. Officially, there are eighty-eight PLANETS 11. They form when clouds of gases are pulled together by gravitational forces. 12. Their position changes with the seasons because of the movements of the Earth. 2 Circle the correct answer. 1. The universe is all the (a) space (b) energy (c) matter, space and energy that exists. 2. A nebula is (a) a cluster of stars (b) a cloud of gas and dust (c) a vast empty space. 8

3. Nebulas surround (a) all the planets (b) the stars (c) the natural satellites 4. Astronomers use (a) Astronomical Units (b) International Units (c) Universal Units 5. Satellites orbit (a) the stars (b) the Sun (c) planets and dwarf planets 6. Mercury and Venus have (a) one satellite each (b) no satellites (c) more than ten satellites each 7. Asteroids can form (a) belts (c) constellations (c) systems 8. The position of the constellations changes with (a) the seasons (b) the way we imagine them (c) the colour of the night sky 9. The orbit of comets is (a) very irregular (b) more or less irregular (c) very elliptical 10. An astronomical unit (AU) is the distance from the Earth to (a) the Moon (b) the Milky Way (c) the Sun Talk about astronomical distances with a partner. How far away is from? It is km / light-years away. Astronomic distances from the Earth Object Distance space station 300 km weather satellite 36,000 km the Moon 384,000 km the Sun 150,000,000 km Pluto 6,000,000,000 km Alpha Centauri 4 light-years 9

3) HOW DOES THE EARTH MOVE? The Earth moves in two different ways: Rotation: The Earth rotates on a slightly tilted axis, always in the same direction. This rotation causes the sequence of day and night. It is day on the half of the Earth facing the sun. It is night on the half facing away from the Sun. Revolution: The Earth s revolution around the Sun is an ellipse. It takes 365 ¼ days to complete the revolution. This is one year. What causes the seasons on Earth? Two factors combine to cause the seasons: 1st. The revolution of the Earth around the Sun. 2nd. The Earth s axis is tilted at an angle of about 23.5º. The tiltt of the axis causes differences in temperature and in the duration of day and night. 10

The Sun s rays strike the Earth in different ways depending on the seasons. - Summer: Solar rays strike perpendicular to the Earth s. - Winter: Solar rays strike the Earth at a steeper angle and produce less heat. The tilt of the axis makes the seasons occur at different times of the year in the Northern and Southern Hemispheres. Spring. The days get longer and the nights get shorter until 21 st June the longest day (summer solstice). Summer. The days get shorter and the nights get longer. On 22 nd September day and night are the same length (autumn equinox). Autumn. The days get shorter and the nights ger longer until 22 nd December the shortest day (winter solstice). Winter. The days get longer and the nights ger shorter. On 21 st March, day and night are the same length (spring equinox). 11

Look at the pictures and observe the differences between Northern and Southern hemisphere. Picture 1 Picture 2 Answer the questions. 1. What is rotation? 2. How long does it take to the Earth to make one complete rotation? 3. How long does it take the Earth to orbit the Sun? 4. What season is it in the Northern hemisphere when the North Pole is tilted towards the Sun? 5. When are days and nights the same length? Fill in the blanks. -night -day -24 The Earth takes hours to rotate on itself. This movement causes us to have and. 12

4) ECLIPSES SOLAR ECLIPSE If the Moon passes between the Sun and the Earth, and blocks off the sunlight, a solar eclipse occurs. LUNAR ECLIPSE If the Moon passes behind the Earth, so the Earth prevents sunlight from reaching the Moon, a lunar eclipse occurs. Use these prepositions in the following phrases: From Behind Between During a solar eclipse, the moon is the Earth and the Sun.. the Earth, the Sun is the moon. Use these prepositions in the following phrases: From Behind In front of. During a lunar eclipse the Earth is... the moon and the Sun..the moon, Earth is the Sun. 13

Circle the correct sentence: 1º The universe a) is static b) is expanding c) is contracting d) doesn t move 2º We live in a galaxy called. a) Universe b) Milky Way c) The solar system d) Earth 3º The second planet of the system solar is a) Mercury b) Venus c) Mars d) Saturn 4º The biggest planet of the solar system is a) Venus b) Earth c) Jupiter d) Uranus 5º In the north hemisphere it s a) Spring b) Summer c) Autumn d) Winter 6º And in the south hemisphere it s a) Spring b) Summer c) Autumn d) Winter 9º In a solar eclipse a) The sun is between the earth and the moon. b) The moon is between the sun and the earth. c) Venus is between the earth and the sun. d) The Earth is between the Sun and the Moon. 14

10º In a lunar eclipse a) The Sun is between the Earth and the Moon. b) The Moon is between the Sun and the Earth. c) Venus is between the Earth and the Sun. d) The Earth is between the Sun and the Moon. 15