Chapter 2 - Planetary Systems - Our solar system

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  • Created by: Georgina
  • Created on: 14-04-13 08:16
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  • Astronomy - Chapter 2 - Planetary Systems - Our Solar System
    • Trans-Neptunian Objects
      • Asteroids
        • Small solid bodies (less than a few hundred kilometres in size but larger than 10 m)
        • Asteroids orbit in the Asteroid or Main Belt between Mars and Jupiter
        • Some asteroids are Vesta (brightest)and Pallas
      • TNOs are objects that orbit the Sun beyond Neptune
    • Planets
      • Dwarf Planets
        • There are 3 dwarf planets that
          • Ceres, Pluto and Eris
      • Venus
        • Venus has a very dense atmosphere
          • Carbon dioxide 97%, Nitrogen 3% and clouds of sulphuric acid
        • 2% of the Sun's light reaches the surface of Venus and the rest is reflected back as much lower energy of infrared wavelengths
        • Venus absorbs most of this reflected heat. This is caused by the high level if carbon dioxide in the atmosphere
        • Carbon dioxide in the atmosphere dissolves into the oceans in vast quantities. Carbonate rocks have formed as a result, ‘locking up’ much of the carbon dioxide in the ground and keeping the atmospheric carbon dioxide at a very low level
        • On Earth water is one of the key factors helping to control the greenhouse effect.
        • The loss of water on Venus prevented this 'locking up' process and the planet was doomed to extreme global warming
        • Outgassing (the release of gases from volcanoes) caused the carbon dioxide and sulphur dioxide levels in the atmosphere on Venus to rise
        • The ‘locking up’ process had virtually stopped on the planet and so these gases added to the levels of heat energy retained by the atmosphere. This is the major reason, together with the fact that Venus is closer to the Sun than the Earth, that Venus has such a high surface temperature.
      • There are 4 rocky terrestrial planets
        • Mercury, Venus, Earth and Mars
      • There are 4 gas giants
        • Jupiter, Saturn, Uranus and Neptune
    • Solar System
      • EARTH
        • Earth has an elliptical orbit around the Sun and so do all the planets but slightly inclined to the ecliptic
      • In our Solar System there are 8 planets and 3 dwarf planets
      • To define an object as a planet they have to have 3 things
        • It has to have an orbit around the Sun
        • It has to be large enough to be spherical
        • It has to have 'cleared it's orbit' of other objects
      • As you move further away from the Sun the temperature drops
    • Key Terms
      • Perihelion
      • Aphelion
      • Greatest
      • Elongation
      • Conjunction
      • Opposition
      • Transit
      • Occultation
    • Centaurs
      • Centaurs are similar to asteroids and comets
      • Named after the half man half horse mythological  creatures
      • They generally orbit the Sun between the orbits of Jupiter and Neptune
      • Some are Chiron, Hidalgo and Asbolus
    • Zodiac Band
      • The Zodiac is the name of the virtual belt in which the planets, Sun, and Moon appear to move about the sky
      • Because the orbits of the planets are not on a perfect plane, the Zodiac band is 16° wide - 8° on either side of the ecliptic
    • Manned Exploration
      • Astronauts face many problems when going out into space
      • Space Adaptation Syndrome - with no 'up' or 'down' astronauts may become disorientated and suffer from headaches, poor concenrationand vomiting
        • Astronauts face many problems when going out into space
      • Some suffer from brittle bones, muscle fatigue and reduced red blood cell count
        • Communication delays
        • Radiation risk - exposed without Earth's 'shield' solar flares are seen as life-threatening
        • psychological problems - living and working with the same people in small spaces can cause irritability, fatigue and low motivation
      • Characteristics of the Planets
        • Mercury: heavily cratered and contains hihlands and lava-filled basins (many parts of it appear to be the same as the moon)
        • Venus: Backward spinning, and has pressure 90x greater than Earth and it also has temperature of 470 C
        • Mars: known as the 'red planet' and has iron-rich rocks and seasonal icecaps and a water-carved canyon called Valles Marineris (450 km) it also has the highest volcano in the solar system - Olympus Mons
          • It also has violent dust storms that range the surface
        • Jupiter: rotates on it's axis in only 10 hours, producing an equatorial bulge and causing dynamic wind systems that split the atmosphere into series of red-brown belts and yellow-white zones
        • Saturn: Similar to Jupiter but reveals less of its structure in  its atmosphere and shows no evidence of long term features like Jupiters GRS
          • Saturns most notable featues is its rings
        • Neptune and Uranus: often regarded as twins (both cold gas giants and similar size and compositionsof hydrogen, helium, methane and ammonia)
      • Ring Systems
        • All 4 gas giants possess ring system above their equator
        • Each ring contains billions of individual particles of ice, rock and dust
        • Jupiter has very dusty dark rings compared to Saturn which are icy and highly relfective

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