Summary of Lecture 2

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Summary of Lecture 2

• Physical characteristics of a planet
• Mass, Size, Volume, Density
• Compared the characteristics of the planets
• mass, size, density, gravity, rotation on axes
• Revolution of planets around the Sun
• Tycho Brache, Johannes Kepler
• Keplers Laws

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Keplers Laws

• Each Planet moves about the Sun in an orbit that
  is an ellipse, with the Sun at one focus of the
  ellipse.
• The planets sweep out equal areas in equal times
  (they move faster when they are closer to the
  Sun)
• P 2 a3

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Summary of Lecture 2

• Description of the planets
• Terrestrial planets atmospheres and water (now
  and in the past)
• Terrestrial planets interiors
• Rocky shell, mantle, core (liquid and solid)
• Terrestrial Planets magnetic fields
• how do we study the interiors of the planets?

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The Earths magnetic field
A bubble around the Earth that protects it from
the solar wind. The atmosphere alone is not
enough protection.
Without magnetic field the solar wind will
collide with the atmosphere, mixes with its upper
levels and change it. (like in Venus?)
electrically charged gas (plasma) that streams
off the Sun at a million miles /hr