ESci-Earth Characteristics

• What makes the earth special?

  • Location: Habitable Zone
  • Planet Mass: Atmospheric mass and plate tectonics
  • Atmospheric Composition: reflectivity and climate balance
  • Have requirements for life
  • Circular Orbits
• Characteristics of the planet Earth to support life

  • The Proximity to the Sun
  • Have near-circular orbits
  • Earth's Magnetic Fields
  • Life-Supporting Rotation
  • The axis tilt is just right to have moderate seasons
  • Size: Atmospheric mass and plate tectonics
  • Earth's structure: Solidity of the Earth
  • It has Liquid Water
  • Has a breathable atmosphere
• Habitable Zone


  The region around a star where the requisite conditions for the existence of life can be met
• The planet is in the "Habitable Zone"
• Anphelion


  Point farthest from the sun in the path of an orbiting celestial body
• Parihelion


  Point nearest to the sun
• Near-circular orbits have no huge ellipses
• Earth's Magnetic Fields


  • The planet can maintain the atmosphere through its magnetic field
  • The sun blasts the Earth with a stream of charged particles called the solar wind and the magnetic field deflects the solar wind
  • Heat from its interior causes the core to convect and mix as the planet rotates on its axis
  • The combination of the hot spinning metal produces the magnetic field
• Mars has lost its magnetic field due to the solar winds
• Life-Supporting Rotation


  • The spinning of the earth on its axis causes the Sun to move across the sky
  • The speed of the rotation is relatively quick so that days and nights are not too long
• Axis tilt


  • The tilt of the Earth's axis causes changes in the season
  • The tilt also causes the summer days to be longer than nights and the opposite for the winter as there is less light to heat the ground
  • Planets should have moderate seasons or biospheric
  • Without the tilt, the planet would be colder (warmer weather could not move poleward)
  • The tilt should not be radical to avoid extreme seasons
• Uranus has a 98 degrees tilt, meaning it essentially spins on its side
• Jupiter is tilted by 3 degrees
• The tilt of the planet earth is 23.4 degrees
• Size: Atmospheric mass and plate tectonics


  • If a planet is too big, it holds onto too much of the light gases and turns into a giant gas planet like Jupiter
  • If a planet is too small, it doesn't have enough gravity to hold onto a life-sustaining atmosphere
• • Diameter of the earth: 12,756 km (7, 926 miles)
  • Circumference or distance around the earth is 40,075 km (24, 901 miles)
• Earth's structure


  • The composition of the planet consists of solid and liquid portions and the atmosphere or gaseous portion
  • Earth is made up of rocks
• Liquid Water


  • The planet has water which is the most necessary chemical for life
  • Water allows easy movement of molecules to/from reactions
  • Allows the creation of complex molecules
  • Can participate in reactions as a source of oxygen or hydrogen
• Breathable atmosphere


  • The atmosphere holds carbon dioxide and other gases that keep the planet warm and protect it from the sun's radiation
  • A blanket for gas traps
  • Redistributes heat
  • Supplies oxygen and CO2
  • It is thick enough to prevent poisonous radiation rays from getting through it
  • Earth's atmosphere is about 100 miles thick
  • Keeps the surface warm
  • Protects it from radiation and meteorites
• Venus's atmosphere is 100 times thicker than Earth and made up of greenhouse gases making the surface too hot for life
• Mars's atmosphere is about 1/100th that of Earth's and too small for significant insulation or shielding
• What is the diameter of the Earth?

  12,756 km (7, 926 miles)
• The Earth has an ozone layer that protects the surface from ultraviolet radiation.