The Earth in the Univers e The Earth in the Universe Geology
The origin of the Universe The position of the Earth in the Universe Distances in the Universe Galaxies The Milky Way Stars: The Sun The Solar System The movements of the planets Planets in the Solar System The Earth s revolution The Earth s rotation The importance of the Earth s movements for living things The Sun, Earth and Moon Oxford University Press España, S. A. Geology 2
The origin of the Universe Oxford University Press España, S. A. Geology 3
The Universe or Cosmos is defined as everything that exists. Oxford University Press España, S. A. Geology 4
The position of the Earth in the Universe Oxford University Press España, S. A. Geology 5
Geocentric model Heliocentric model Saturn Saturn Jupiter Jupiter Moon Mars Sun Venus Mercury Moon Mars Earth Venus Mercury Earth Sun The Earth is spherical and is the centre of the Universe. The Sun, the Moon and the planets revolve in concentric circles around the Earth. The stars are fixed on a dome that also revolves around the Earth The Sun does not move and is in the centre of the Universe. All the planets revolve around the Sun in concentric circles. The Earth rotates on its axis and the Moon revolves around the Earth. The stars are fixed on a dome that does not move. Oxford University Press España, S. A. Geology 6
Distances in the Universe Oxford University Press España, S. A. Geology 7
Light year A light year is equivalent to the distance travelled by light in one year. Light travels at a speed of 300000 km per second. 1 year x 365 days x 24 hours x 3 600 segundos x 300 000 km/s = 9.5 billion km Parsec A parsec (pc) is equivalent to 3.26 light years. La unidad astronómica An astronomical unit (AU) is the distance between the Earth and the Sun. 1 UA = 150 million km Oxford University Press España, S. A. Geology 8
Galaxies Oxford University Press España, S. A. Geology 9
Galaxies are huge group of stars, nebulae and interstellar dust and gas held together by the force of gravity. eliptical spiral barred spiral irregular Nebulae are huge clouds of gas. They are formed by concentrations of hydrogen and helium as well as interstellar dust. Oxford University Press España, S. A. Geology 10
The Milky Way Oxford University Press España, S. A. Geology 11
The Milky Way is a spiral galaxy, located in a galaxy cluster called the Local Group. disk nucleus halo Oxford University Press España, S. A. Geology 12
Stars: The Sun Oxford University Press España, S. A. Geology 13
Stars are large spheres of gas spheres made mostly of hydrogen and helium. Stars release energy in the form of light and heat. Type Temperature (ºC) Colour Example O >30000 Violet-blue Naos B 10 000-30 000 Blue Rigel A 7500-10 000 White Vega F 6000-7500 White-yellow Protion G 5000-6000 Yellow Sun K 3500-5000 Orange Arcturus M 2000-3000 Red Betelgeuse photosphere core The Sun is a medium-sized yellow star with a surface temperature of 5500 ºC. Oxford University Press España, S. A. Geology 14
The Solar System Oxford University Press España, S. A. Geology 15
The Solar System consists of the Sun and the celestial bodies that orbit it. Pluto (dwarf planet) path of Halley s comet Composition: Planets Venus Earth Sun Mercury Mars Dwarf planets Satellites Saturn asteroid belt Jupiter Asteroid belt Uranus Neptune Comets Oxford University Press España, S. A. Geology 16
The movements of the planets Oxford University Press España, S. A. Geology 17
Revolution (year) Neptune Mercury Sun Pluto (dwarf planet) Venus Earth Venus 177⁰ Mercury 0.1⁰ Mars 25⁰ Earth 23.5⁰ Jupiter 3⁰ Rotation (day) Saturn 27⁰ Uranus 98⁰ Pluto (dwarf planet) 120⁰ Neptune 30⁰ Oxford University Press España, S. A. Geology 18
Planets in the Solar System Oxford University Press España, S. A. Geology 19
Inner planets The inner planets are small, have very little or no atmosphere and have a rocky surface. Outer planets The outer planets are very large and have a gaseous atmosphere. They are surrounded by rings and their surface is in a gaseous or liquid state. Oxford University Press España, S. A. Geology 20
The Earth s revolution Oxford University Press España, S. A. Geology 21
The Earth moves around the sun in an elliptical orbit. It takes the Earth 365 days, 5 hours and 49 minutes to complete one revolution. perpendicular to the ecliptic plane 23.5⁰ rotation axis revolution winter summer Sun summer winter smaller angle = bigger area bigger angle = smaller area ecliptic plane Oxford University Press España, S. A. Geology 22
The Earth s rotation Oxford University Press España, S. A. Geology 23
The Earth takes 23 hours and 56 minutes to complete one rotation on its axis. Rotation causes day and night. Oxford University Press España, S. A. Geology 24
The importance of the Earth s movements for living things Oxford University Press España, S. A. Geology 25
Many trees lose their leaves in autumn, when they detect a decrease in the hours of daylight. Trees then sprout new leaves in spring, with the increase in the hours of daylight. Flowering and forming of fruits also depend on temperatures and hours of daylight and darkness. Not all plants flower and form fruit in the same season. The mating and breeding seasons of many animals start when the days get shorter and temperatures lower. Some birds migrate at certain times of the year Oxford University Press España, S. A. Geology 26
The Sun, Earth and Moon Oxford University Press España, S. A. Geology 27
Moon Earth 5.15⁰ ecliptic plane Phases of the Moon first quarter solar eclipse Eclipses lunar eclipse Tides spring tides full moon new moon last quarter neap tides Oxford University Press España, S. A. Geology 28