Planets

• The Solar System


  A vast cosmic neighborhood consisting of stars (like the Sun), planets, dwarf planets, asteroids, comets, and moons
• The Solar System


  • Its edge is estimated to be 9 billion miles from the Sun, surrounded by the giant, spherical Oort Cloud (marking its far outer reaches)
• Inner planets

  • Mercury
  • Venus
  • Earth
  • Mars
• Inner/Terrestrial planets


  Have rocky surfaces
• Outer planets


  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• Outer/Jovian planets or Jupiter-like planets


  Have enormous sizes and are mostly made of gases despite their solid cores
• Gas giants


  • Jupiter
  • Saturn
• Ice giants


  • Uranus
  • Neptune
• Asteroid belt


  Separates the inner planets to the outer planets
• Dwarf planets


  Like Pluto (once a planet in the solar system) in the outer regions
• Pluto reclassified as a dwarf planet by the International Astronomical Union (IAU)


  2006
• Pluto


  • A cold, rocky world with thin atmosphere
  • Has several moons, including Charon, its largest one
• Mercury


  The closest planet to the Sun and the smallest in the solar system (only a little larger than the Earth's moon)
• Mercury's orbit


  Zips around the sun in only 88 days
• Mercury


  • Experiences dramatic changes in its day and night temperatures
  • Reaches a scorching 840 F (450 C) during the day (hot enough to melt lead) while temperatures drop to -290 F (-180 C) during night time
  • Has a very thin atmosphere (cannot hold onto heat) primarily composed of oxygen, sodium, hydrogen, helium, and potassium
  • Unable to deflect incoming meteors, thus, its surface is pockmarked with craters
  • Its north pole was found with water ice and frozen organic compounds
• Mercury is the messenger of the Roman gods
• Mercury has a diameter of 3,031 miles (4,878 km)
• Mercury has 0 moons
• Venus


  The second planet from the sun and the hottest in the solar system
• Venus


  • Has a thick atmosphere that is extremely toxic and composed of carbon dioxide and sulfuric acid clouds (an extreme example of the greenhouse effect since it traps heat) causing extreme temperatures
  • The average temperature is 900 F (465 C)
  • The pressure at the surface would crush and kill you at 92 bar
  • Spins slowly from the east to west, the opposite direction of most of the planets (retrograde rotation)
  • Sometimes referred to as Earth's twin (similar size; radar images beneath its atmosphere reveal numerous mountains and volcanoes)
• Venus is the Roman goddess of love and beauty
• Venus has a diameter of 7,521 miles (12,104 km)
• Venus has 0 moons
• Earth


  The third planet from the Sun and the fifth largest in the solar system
• Earth

  • A water world with two-thirds of the planet covered by water
  • Its atmosphere is rich in nitrogen and oxygen
  • The only world known to harbor life
  • Rotates on its axis at 1,532 feet per second (467 meters per second), slightly more than 1,000 mph (16,000 kph), at the equator (spins quickly at the equator)
  • Zips around the Sun at more than 18 miles per second (29 km per second) (travels at high speeds around the Sun)
• Earth's name comes from the German word "Die Erde", meaning "the ground"
• Earth has a diameter of 7,926 miles (12,760 km)
• Earth has 1 moon (the Moon)
• Mars


  The fourth planet from the Sun and is a cold, desert-like planet covered in iron oxide dust that gives the planet its signature red hue
• Mars


  • Shares similarities with Earth (rocky, has mountains, valleys, canyons, and storm systems ranging from localized tornado-like dust devils to planet-engulfing dust storms)
  • Studies suggest that at one point billions of years ago, the planet was a much warmer, wetter world (rivers and oceans existed)
  • Though its atmosphere is too thin for liquid water to exist, remnants of that wetter planet still exist today
  • Sheets of water lie beneath the Mars' surface and at both poles are ice caps made in part of frozen water and possible underground lakes
  • Ancient Mars is believed to have conditions that support life like bacteria and other microbes
  • One of the most explored planets in the solar system in hope that signs of past life and the possibility of current lifeforms may exist
• Mars is the Roman god of war
• Mars has a diameter of 4,217 miles (6,787 km)
• Mars has 2 moons (Phobos and Deimos)
• JUPITER

  • The fifth planet from the Sun
  • The largest planet in the solar system
  • More than twice as massive as all the other planets combined
  • Has swirling clouds that are colorful due to different types of trace gases including ammonia ice, ammonium hydrosulfide crystals, water ice, and water vapor
  • Famous for its Great Red Spot, a giant, long-lasting storm more than 10,000 miles wide
  • The Great Red Spot raged more than 400 mph for the last 150 years
  • Has a strong magnetic field with many moons including the largest one in the solar system, Ganymede
• Name of Jupiter

  The ruler of the Roman gods
• Jupiter has a diameter of 86,881 miles (139,822 km)
• Jupiter has 95 moons
• SATURN


  • The sixth planet from the Sun
  • Famous for its large and distinct ring system
  • When first studied by Galileo Galilei in the early 1600s, it was thought to be an object with three parts (planet and two large moons) not knowing that it was a planet with rings until he drew it
  • 40 years later, Christiaan Huygens proposed that they were rings
  • The rings are made of ice and rock though scientists are not yet sure how they formed
  • The planet is mostly hydrogen and helium and it has numerous moons
  • Has an average density less than water
• Name of Saturn


  The Roman god of agriculture
• Saturn has a diameter of 74,900 miles (120,500 km)