8. The Universe and the Earth. BIOLOGY AND GEOLOGY. ANAYA 1ST ESO. Ana Rupérez Romero

Transcription

1 8. The Universe and the Earth BIOLOGY AND GEOLOGY. ANAYA 1ST ESO. Ana Rupérez Romero

2 Ancient civilizations Mythology Earth motionless and flat Sky was a dome with the stars. Greeks Earth is spherical body Earth floats in space like other celestial bodies

3 Geocentric model Ptolemy in 2nd century AD Earth round and at the center of the universe Other celestial bodies revolved around Sphere with fixed stars Planets known: Earth, Venus, Mars, Jupiter and Saturn

4 Heliocentric model Aristarchus and Copernicus The Sun is at the center of the universe The other planets revolve (orbit) around the Sun. The Moon orbits the Earth. The Stars are on a fixed Sphere.

5 Current idea of universe The sun is not at the center of the Universe, only at the center of the Solar System. The orbits of the planets are not circles, but elipses. The stars are not in a fixed sphere but in a Galaxy. The universe is all MATER, ENERGY AND TIME The Universe is expanding: galaxies are separating Occupies an enormous space The BIG BANG was the first explosion.

6 Some definitions: Universe: All matter energy and time that exist. It occupies an enormous space ( million light years) Galaxies: collections or stars and nébulas. Nebulas: clouds of dust and gas. They are the places where stars are born and they can also come from explosions of stars. Stars: are enormous spheres of matter that emit energy (with nuclear reactions transforming hydrogen into hellium) Solar systems: formed ussually by one star, planets, moons, asteroids, comets, dwarf planets. Big Bang: is the name for the first explosión that created the universo. Galaxies are moving away from each other. The universe is getting bigger and expanding. It happened around million years ago.

7 Video Relative sizes

8 Distances in the universe 1 Astronomic Unit: AU is km. 150 million km Speed of light: km/s 1 year has: 60*60*24*365= seconds s x km/s is the distance that light covers in 1 year Light year: km, 9,5 billion km Closest star to the Earth: Alpha Centauri (4,3 light years>> 41,32billion km)

9 Our solar system Located in the Milky Way ( billion stars) The Milky Way belongs to the Local Group (20 galaxies) The Local Group is in the Virgo Supercluster. Celestial bodies in the Solar System: The Sun Planets (8) Satellites Dwarf planets Asteroids Comets

10 The Sun video

11 The sun Medium sized star. Located in one of the spiral arms of the Milky Way Movements: rotation around its axis and with the Galaxy. Sends energy in forms of heat and light. Also sends solar wind (with particles) video of solar wind. Sun age: 5000 million years Sun will die in 4500 million years

12 Types of stars

13 Planets Spherical celestial bodies that orbit a star. Reflect sunlight (they can t produce their own light) They travel in elliptical orbits around the sun All the orbits are located in the same plane: the ecliptic plane ROCKY or INNER: Mercury, Venus, Earth and Mars Small, made of rock, weak atmosphere. GAS or OUTER: Jupiter, Saturn, Uranus, Neptune. Big, small solid nucleus, large and thick atmosphere, many satellites and rings.

14 Planets of the solar system Rocky or inner planets: Rocky surface Dense materials Atmospheres tenuous (tenues) Smaller in size Mercury, Venus, Earth and Mars Gaseous or outer planets Further Low density substances in gaseous state Atmospheres very thick covering a tiny solid nuclei Size very large and a slower speed

15 Satellites Spherical (or not) bodies that orbit a planet. Rocky planets have none, one or two satellites. Venus and Mercury: none Earth: one (the Moon). Mars:two (Phobos and Deimos) Gas planets have many satellites. Jupiter: more tan 60. Galilean Satellites are 4: Callisto, Europa, Io and Ganimedes.

16 More definitions Dwarf planets: spherical bodies (Pluto and Ceres) that orbit a star but their orbits are not free of other objects. Asteroids: Irregular rocky bodies that orbit around the Sun (in the Asteroid Belt or Kuiper belt). The trajectory can change.

17 Comets: small bodies made up of rock and ice. Come from the Kuiper belt. Very elliptical orbits. The fragments can become meteorites. Meteor shower or shootting stars

18 Watch the following videos about our solar system: Our solar system The origin of the solar system: x?videoid=55507&categoryid=2813

19 Solar System: Formation of Solar System: video 1(Stephen Hawkins), video 2

20 Formation of the solar system 1. The nebula begins to condense and revolve. 2. The rotation caused the nebula to take the shape of a flat disc: the protoplanery disc (most matter at the center) 3. The matter at the center concentrates more and more>> pressure and temperatura make nuclear reactions>>> the Sun is formed. 4. The rest of the materials were send outside the center and revolved around the Sun at different distances>> Planetesimals were formed (the heaviest one close to the Sun will form rocky planets and the lighter ones will form the gas planets.) 5. Planetesimals attract the materials in their orbits and formed larger and larger planetesimals that eventually became planets.

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22 Crab nebula 5 th July The story of a supernova. Crab nebula is the first supernova that has been witnessed in the whole world (China, America, native Anasazi..). During the explosion it could be seen even at daytime and later stayed visible for 22 months Crab nebula is 6300 light-years away from us. Therefore, the real explosion was in 5246 before Christ although its light didn t arrive to us until later. Explosion Supernova 5246 BC Observed 1054 AC Year 0

23 Some constellations of the Milky Way Constellation: group of stars forming a recognizable pattern (drawing) that is named after the form of the figure (mythological figure). The sky is divided into 88 regions called constellations. Stars in a constellation are not closed together, they look together because apparently have the same brightness. Orion

24 Finding the North: Pollaris Ursus Major or Big Dipper is one of the constellations that can be seen the whole year because they are close to Polaris. They are named circumpolar. Other circumpolar constellations are: Casiopea, Perseus, Draco or Cepheus Stars in a costellation are at different distances from us.

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27 Meanings of the names of the planets and curiosities more curiosities planets like the moon PLANET CURIOSITY Mercury God Messenger of Roman gods. Faster. Smaller planet, no atmosphere, no moons, 88 days revolution, 59 days rotation. 430ºC at day, -170 degrees at night Venus Godess of love and beauty. Clouds of carbón dioxide. White and dense atmosphere. Surface very hot. Lava. It rains sulphuric acid. Morning star. Evening star. Second brightest object after the moon. Similar size to Earth. High greenhouse effect. It rotates in the other direction. Impact of something turned it upside down Earth Life. Water 3 states (solid, liquid, gas). Temperature of 15 degrees of average. Axis tilted 23,5 degrees>> seasons Mars God of war. Red planet. Smaller than Earth. No internal activity. Olympus (22km). Rests of wáter. Ice caps. Pathfinder explore>> bacterias. Future colony, Two moons: Phobos, Deimos Jupiter King of Gods. Bigger. Storm 200 years. Faster rotation (10hours) Magnetosphere. Aurora. 4 main moons: Europa, Callisto, io, Ganymedes. Discovered by Galileo with telescope (1610) Atmosphere with stripes. Hydrogen and hellium. Weight higher than all the other planets together Saturn Second big planet. Titan. Rings of ice and gas.1km thick. More tan 60 satellites. Titan has atmosphere. Very light, it would float. Is the farthest planet you can see without telescope. Uranus Neptune God of air. Spins like from a side, like a Rolling ball. Blue. Several moons. Rings very thin God of oceans and wáter. Blue. Farthest planet. Similar to Uranus in size

28 Our planet: the Earth The movements of the Earth The Earth moves in two different ways: Rotation. Revolution. ch?v=lkwym-m8o0c

29 Rotation The Earth rotates (spins) on its own axis. Its axis is an imaginary line between the North Pole and the South Pole. The axis is tilted 23.5º with respect to the perpendicular line to the ecliptic plane

30 The consequences of rotation The rotation of the Earth every 24 hours causes day and night. It is day time on the side of Earth where the sun shines. On the other side of Earth is night. 0DaV8N8

31 The consequences of rotation Rotation sense is counterclockwise. Sunrise or dawn: when the sun first appears in the morning>> EAST Sunset or twilight: the sun disappears in the evening>> WEST

32 Revolution The Earth revolves around the Sun. The Earth takes 365 days, 6 hours and 9 minutes to complete the revolution = a sideral year.

33 The consequences of revolution: the seasons Two factors cause the seasons: The revolution of the Earth around the Sun The tilt of the Earth s axis of rotation respects to the Plane of the Ecliptic. Video on seasons solstices and equinoxes X3Y5bzNDiU

34 Solstices equinoxes and seasons

35 Solstices and equinoxes Solstices: Maximum difference between day and night. Equinoxes: Day and night have the same length. Sun is at the highest or lower point. December, 21/22 is the shortest day June, 21/22 is the largest day Sun hits perpendicular to the equator. March, 20/21 September 22,23

36 The seasons in the Northern Hemisphere During the summer in the northern hemisphere, the temperature is higher because there are more hours of daylight and because the Sun rays hit the Earth surface at an angle of 90º. During the winter, Sun rays are more tilted and that s why is colder. In the South Hemisphere is the opposite.

37 During the seasons, temperature changes depending on angle at which the Sun s rays hit the Earth.

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39 Our satellite: the Moon Movements of the moon: Rotation of the moon: It takes 27.3 Earth days to rotate on its axis. Revolution of the moon: Moon orbits the Earth every 27.3 Earth days. Libration (see the gif on this page. The libration is that Little movement) Same side of Moon always facing the Earth. (there is a far side of the moon we never see) Video on Moon phases Origin and formation of the moon

40 Phases of the moon Moon calendar New moon First quarter (crescent moon) Last quarter or Third quarter (decreasing moon) The 4 phases repeat every 29 days (7 days each main phase) Full moon

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42 Eclipses Eclipses: Solar eclipse; the Moon is alligned with the Earth and the Sun. Lunar eclipse: the Earth is between the Sun and the Moon.

43 Tides Tides: Periodical rise and fall of the sea level. They are caused by the gravitational force of the Moon and, to a lesser extent, the Sun on the water masses of the Earth. Images of high/low tides High tides: the sea level rises Low tides: when the sea level moves down. Tide changes every 6 hours. There are 2 high tides and 2 low tides every 24 hours

44 Spring tides (mareas vivas) and neap tides (mareas muertas)

45 Tides Neap tides (mareas muertas)>> First and last quarters. Little difference between high and low tides sea levels. Spring tides (mareas vivas) >> Full moon and new moon Big difference between high and low tides sea levels.