Science 6

• Nebular theory


  The sun and planets are formed from a rotating disk of dust and gases
• Nebula


  A cloud of gas and dust in space that will form heavenly bodies over a very long time
• Types of planets

  • Terrestrial planets
  • Jovian planets
• Terrestrial planets

  Also called the inner planets
• Inner planets

  • Mercury
  • Venus
  • Earth
  • Mars
• Mercury


  • Nearest planet to the sun
  • Has many craters due to no atmosphere
  • Has no moons
  • One rotation is 58 days 15 hours 30 minutes
  • One revolution is 88 days
  • Fastest planet
• Venus


  • Second planet from the sun
  • Brightest object in the sky besides the sun
  • Commonly referred to as the morning and evening star
  • Twin planet of Earth
  • Hottest planet due to thick CO2 atmosphere and greenhouse effect
  • Clouds are mostly sulfuric acid
  • Rains are acid rain
  • Surface has volcanoes and mountains
  • First planet studied with space in 1962
  • No moons
  • Gravity as strong as Earth
  • One rotation is 116 days 18 hours
  • One revolution is 225 days
  • Rotates only twice per year
• Earth


  • Third planet from the sun
  • Only living planet
  • Rich in liquid water
  • Has an atmosphere that supports and protects life
  • Atmosphere burns most meteors before reaching surface
  • Has one large moon
  • One rotation is 23 hours 56 minutes
  • One revolution is 365.25 days
• Mars


  • Known as the red planet
  • Surface appears red/yellow due to iron oxide
  • Atmosphere is 18% and mostly CO2
  • Has water in atmosphere but not enough to form clouds
  • One rotation is 24 hours 37 minutes
  • One revolution is 687 days
  • Has the largest volcano in the solar system, Olympus Mons
  • Gravity is 2/5 as strong as Earth
  • Has two irregularly shaped moons, Phobos and Deimos
• Mercury, Venus, Earth, and Mars are called terrestrial planets because they have rocky surfaces and metal cores
• Asteroid belt


  Group of asteroids found between the orbits of Mars and Jupiter, separating the terrestrial and Jovian planets
• Outer planets (Jovian or gas giants)


  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• Jupiter


  • Largest gaseous planet
  • More than 11 times the size of Earth
  • Generates strong gravitational force
  • Atmosphere is hydrogen, helium, methane, ammonia, and water vapor
  • Has a faint dust ring
  • Has at least 63 moons, including the 4 Galilean moons of Ganymede, Callisto, Europa, and Io
  • Ganymede is the largest moon in the solar system
  • Io has active volcanoes
  • Callisto is mostly rock and ice
  • Has a large counterclockwise rotating storm called the Great Red Spot
  • One rotation is 9 hours 56 minutes
  • One revolution is 12 years
• Saturn


  • Second largest planet
  • Lowest density
  • 9.5 times larger than Earth
  • One rotation is 10 hours 39 minutes
  • One revolution is 29 years
  • Atmosphere is hydrogen, helium, methane, and water vapor
  • Has at least 31 moons, the largest being Titan
• Uranus


  • Third largest planet
  • Has a system of 11 thin dark rings
  • Atmosphere is hydrogen, helium, and methane which gives it a bluish-green color
  • Radiates the same amount of solar energy it receives
  • Axis of rotation is tilted 84 degrees, resulting in its north pole facing the sun for half of its 84-year revolution
  • One rotation is 17 hours 14 minutes
  • One revolution is 84 years
  • Gravity is a little stronger than Earth
  • Has at least 21 moons, the largest being Titania
• Neptune


  • Fourth largest planet
  • Has an elliptical orbit
  • Atmosphere is mostly methane, giving it a bluish-green color
  • Has a dark storm called the Great Dark Spot
  • Has the fastest winds in the solar system
  • Has at least 11 moons, the largest being Triton
  • One rotation is 16 hours 6 minutes
  • One revolution is 165 years
• Planets in order from closest to farthest from the sun

  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• Dwarf planets


  Smaller planets that do not meet the full criteria to be considered a planet, such as Pluto and Ceres
• Pluto


  • Was previously considered the 9th planet until 2006, when it was reclassified as a dwarf planet due to the discovery of the Kuiper Belt beyond its orbit
• Ceres


  • Largest asteroid, orbiting between Mars and Jupiter
  • Has enough self-gravity to be round, qualifying it as a dwarf planet
• A person who studies heavenly bodies is called an astronomer
• Earthquake


  Sudden movement or vibration of the earth's rocky outer layer
• Earthquake


  • Caused when rock masses suddenly shift in position
  • Energy stored in the rock masses is transmitted onto the surface in the form of seismic earthquake waves
• Crustal plates


  • Outer shell of the earth
  • Surface along which crust moves is called a fault line
• Seismometer


  • Instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions and explosions
  • Usually combined with a timing device and a recording device to form a seismograph
• Magnitude


  Quantitative measure of an earthquake's strength in terms of energy released
• Intensity


  • Qualitative measure of an earthquake's severity in terms of damages caused at a particular location
  • Generally higher near the epicenter
• Focus


  Actual location where fault movement begins, below the earth's surface
• Epicenter


  Point at the land surface directly above the focus
• Types of natural earthquakes

  • Tectonic earthquakes
  • Volcanic earthquakes
• Tectonic earthquakes


  Produced by sudden movement along faults and plate boundaries
• Volcanic earthquakes


  Produced by the movement of magma beneath the volcanoes
• Tectonic earthquakes


  Cause collapse of different structures
• Volcanic earthquakes


  Cause explosions
• Volcanic earthquake


  • Caused by movement of magma beneath the surface of the earth
  • Pressure changes where the rock around the magma has experienced stress
  • Stress can cause the rock to break or move
• Scientists cannot predict earthquakes, but can point out where fault lines are to know where earthquakes are likely to occur
• The largest earthquake ever recorded was in Chile in 1960, measuring 9.6 on the Richter scale
• The largest earthquake in the US was a 9.2 magnitude in Alaska in 1964
• Earthquakes can cause tsunamis
• Movement of tectonic plates forms large mountain ranges like the Himalayas and the Andes