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Notes on Earth in Space

Chapter 1-1

pages  4-13

 

The Earth in Space:
  • 3rd planet from the sun
  • The axis is an imaginary line on which the Earth rotates (spins) in space.
  • The Earth's movement in space is what causes day and night and the seasons
  • Earth moves in an elliptical orbit (oval-shaped)

Day and Night:

  • The rotation of the earth on its axis causes day and night
  • The period of rotation is about 24 hours = 1 day
  • The length of day and night changes because earth's axis is not straight up and down, it is tilted at an angle of 23.5 °

A Year on Earth:

  • Earth revolves in an orbit around the sun.
  • The period of revolution is about 365.26 days = 1 year
  • After 4 years the .26 of a day each year causes an extra day to be added to the month of February, you will have 29 days that year (Leap Year)
     

Seasons on Earth:

  • The seasons are causes by the tilt of Earth's axis and the revolution of the Earth around the sun
  • The part of Earth having summer is not closer to the sun; it is tilted toward the sun.
  • When the northern hemisphere is tilted toward the sun, it is experiencing summer, while the southern hemisphere will be tilted away and experiencing winter.

 

  • Summer Solstice:
    o Northern hemisphere is tilted toward the sun
    o Beginning of summer
    o longest day of the year;
    o Sun is at the highest point in the sky
    o June 20th or 21st

 

  • Winter Solstice:
    o Northern hemisphere is tilted away from the sun
    o Beginning of winter
    o shortest day of the year;
    o Sun is at the lowest point in the sky
    o December 21st or 22nd

 

  • Equinoxes:
    o neither the north pole or south pole is tilted toward the sun.
    o Equal length of day and night
  • Vernal Equinox:
    o Beginning of spring
    o March 20th or 21st
  • Autumnal Equinox:
    o Beginning of fall
    o September 22nd or 23rd

The Magnetosphere: The Earth acts like a giant magnet in space

  • Inner core of Earth made of the metals iron and nickel
  • This acts like a magnetic bar that stretches from pole to pole
  • This creates a force field that stretches into the space around the Earth
  • The solar winds blow this magnetic field around, often changing its shape
    ¨Van Allen Radiation Belts: are the two doughnut shaped regions of the magnetosphere that trap charged particles
    ¨ Sometimes these charged particles crash into each other causing beautiful bands of light to form; these are called auroras
    ¨ Aurora Borealis is the band of light in North pole -
         ·visible in the Northern Hemisphere
    ¨Aurora Australis is the band of light in the South pole -
         ·Visible in the Southern Hemisphere