Science T2

• Sun


  A star of medium size, looks bigger and brighter than all other stars because it is closer to Earth
• Without the sun there would be no life on Earth
• Sun


  A burning ball of gases made up of hydrogen and helium
• Nuclear reaction in the sun

  Hydrogen atoms constantly react to form helium, producing vast amounts of energy from light and heat
• Structure of the sun

  • Core is the hottest part where hydrogen changes to helium, heat and light move from core to outer surface and are released into space
• Solar system


  The sun and the objects in the region of space around it
• Objects in the solar system

  • Planets
  • Moons
  • Asteroids
  • Ice
  • Dust
  • Dwarf planets
• Criteria for a planet

  • Travels around the sun
  • Able to keep its orbital path clear of other objects
  • Almost spherical in shape
• Eight planets


  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• Inner rocky planets


  Mercury, Venus, Earth, Mars - made of rock
• Outer gas giants


  Jupiter, Saturn, Uranus, Neptune - made of gases and liquids, larger than terrestrial planets, furthest from sun
• Dwarf planet


  A planet that is not able to clear other objects in its path
• Dwarf planets


  • Pluto
  • Ceres
  • Eris
  • Makemake
• Mercury


  • Closest planet to sun, very hot on day side, freezing on night side due to thin atmosphere
• Venus


  • Thick atmosphere of carbon dioxide traps sun's heat, raising temperatures to 471°C
• Earth


  • Thick atmosphere with oxygen, abundant water, temperatures range from -40 to 40°C, only planet able to support life
• Mars


  • Cold desert-like surface, similar temperatures to Earth but colder on average, thin atmosphere prevents liquid water
• Jupiter


  • Biggest planet, very cold at -148°C due to distance from sun, thick atmosphere of hydrogen and helium, giant storms
• Saturn


  • Thick atmosphere of hydrogen and helium, average temperature of -178°C, distinctive rings made of ice and solid particles
• Uranus


  • Only planet that spins on its side, very cold at -216°C, atmosphere of hydrogen, helium, water, methane, ammonia
• Neptune


  • Furthest planet from sun, takes 165 years to orbit, extremely cold and dark at -218°C, similar atmosphere to Uranus
• Moon


  A body that revolves around a planet, reflects light from the sun
• Moons of planets


  • Mercury and Venus have no moons
  • Earth has 1 moon
  • Mars has 2 moons
  • Gas giants have over 60 moons each
• Asteroid


  A rock found in space, mostly orbiting between Mars and Jupiter in the Asteroid Belt
• Asteroids


  • Made of similar material to terrestrial planets but too small to be called planets, have an iron core like Earth
• Meteoroid


  A solid object in space smaller than an asteroid, most come from the Asteroid Belt
• Meteoroid entering Earth's atmosphere

  1. Starts to burn up, creating a shooting star

  2. Sometimes crashes into ground as a meteorite
• Comet


  A body made of frozen gases and rock that comes from beyond the furthest planet, has a head, coma, and tail
• Comet approaching the sun

  Ice melts, releasing gases and dust to create the coma and tail
• Solar system


  • Looks like a flat disc, with the sun at the centre and all objects orbiting around it in the same direction
• Gravity


  The natural force that attracts objects to each other, the more mass an object has the stronger its gravitational pull
• The sun has the most mass and therefore the strongest gravitational pull, which is why planets and other objects orbit around it
• Kuiper Belt


  A ring of ice and rocky objects beyond the orbit of Neptune
• Oort Cloud


  Thought to be even further away than the Kuiper Belt, a spherical cloud of dust and gas surrounding the solar system
• Comets that enter the solar system are believed to come from the Kuiper Belt and Oort Cloud
• Earth


  • Third planet from the sun, only planet known to support life
• Temperature on Earth


  Distance from the sun is the most important factor, Earth is the perfect distance to sustain life
• Sunlight reaching Earth


  Provides energy that makes life possible, powers photosynthesis in plants, heats parts of Earth to create wind and rain
• Water on Earth


  Exists in liquid, gas, and solid states, constantly cycles through the water cycle
• Oxygen


  Makes up 21% of Earth's atmosphere, essential for life, produced by photosynthesis in plants