THE MOON

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THE MOON
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Definitions

• Year time that a planet takes to go around the
  sun once.
• Revolution motion of a body orbiting another
  body in space
• Prograde rotation counterclockwise spin of a
  planet or moon as seen from above the planets
  North Pole (rotates in the same directions as the
  suns rotation), EARTH

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• Retrograde rotation the clockwise spin of a
  planet or moon as seen from above the planets
  North Pole. Venus, Uranus
• Greenhouse effect carbon dioxide traps thermal
  energy from sunlight, causes surface temperatures
  to increase
• Gas Giants planets that have deep, massive
  atmospheres rather than hard rocky surfaces like
  those of the inner planets

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• Satellites natural or artificial bodies that
  revolve around larger bodies such as planets.
  All planets, except MERCURY and VENUS have
  satellites.
• Phases change in the sunlit area of one
  celestial body as seen from another celestial
  body.
• Eclipse an event in which the shadow of one
  celestial body falls on another

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Measuring Distance in Space

• Astronomical Unit the average distance between
  the Earth and the Sun
• Using the speed of light light travels at about
  300,000 km/s in space
• In 1 second, light travels 300,000 km.
• In 1 minute, light travels nearly 18,000,000 km
  LIGHT MINUTE
• 1 AU 8.3 light minutes

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Astronomical Unit the average distance between
the Earth and the Sun
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Solar System Divided into two main parts

• Inner solar system contains four planets that are
  closest to the sun (Mercury, Venus, Earth and
  Mars)
• More closely spaced
• Terrestrial planets
• Dense and rocky

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Inner Planets
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• Outer system contains 4 planets farthest from the
  sun. (Jupiter, Saturn, Uranus, Neptune)
• Composed mostly of gas
• GAS GIANTS
• Pluto is now considered a satellite of Neptune
  Its not composed of gas is small, dense and
  rocky

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The Outer Planets
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Why did the Earth have such good fortune?

• Its just at the right distance from the Sun
• Warm enough to keep most of its water from
  freezing
• Cool enough to keep its water from boiling away
• Liquid water is a vital part all living things
  depend on

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The surface of bodies that have no atmosphere
preserve a record of almost all of the
impacts that the bodies have had.
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LUNAR ORIGIN

• 3 possible explanations for the moons
  formation
• Moon was a separate body captured by Earths
  gravity
• Moon formed at the same time and from the same
  materials as the Earth
• The newly formed Earth was spinning so fast that
  a piece flew off and became the moon

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• When a moon rock was brought back, scientist
  found that the composition of moon was similar to
  that of the Earths mantle.
• CURRENT THEORY large, Mars-sized object
  collided with Earth while Earth was still
  forming. Collision was so violent that part of
  the Earths mantle was blasted into orbit around
  Earth to form the moon.

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Origin of the moon
IMPACT
EJECTION
FORMATION
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Basic Moon Stats

• 384,000 Km away
• 3476 km in diameter (1/4 of Earth)
• Density 3.3 g/cc
• Mass is 1/80 of Earth
• Gravity is 1/6 of Earth

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Basic Moon Stats

• Temp varies from -175 C to 100 C!!!
• Age is similar to Earth
• No Atmosphere or water
• Revolves once every 27.3 days
• Rotates once every 27.3 days
• Blue Moon 2 full moons in one month (1)

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Exploration of the Moon

• Apollo Moon Landing Project
• Neil Armstrong walked on moon in 1969
• Ended in 1972
• Humans havent been back since

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• Perigee-moon is closest to Earth
• Apogee-moon is furthest from Earth

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• Perigee Apogee
• 356410 km 406700 km
• 5 Variation in distance from Earth!

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PHASES OF THE MOON

• The different phases are due to its changing
  position
• WAXING sunlit fraction that we see is getting
  BIGGER (lit on the RIGHT)
• WANING sunlit fraction that we see is getting
  SMALLER (lit on the LEFT)

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PHASES OF THE MOON
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PHASES OF THE MOON

• Total amount of sunlight that the moon gets
  remains the same Half the moon is always in
  sunlight
• Because the moons period of rotation is the same
  as its period of revolution on Earth you always
  see the same side of the moon

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PHASES OF THE MOON
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Does the Moon Rotate?

• We always see the same side of the Moon its
  rotation and revolution are equal
• Synchronous Rotation

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The Moon and The Tides
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Neap Tide

• Neap Tide-A weaker than average tide due to the
  conflicting gravitational forces of the sun and
  moon

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Spring Tide

• Spring Tide-A stronger than average tide due to
  the gravitational forces of the sun and moon
  working together (3)

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ECLIPSES

• When the shadow of one celestial body falls on
  another, an eclipse occurs.

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SOLAR ECLIPSE

• SOLAR ECLIPSE happens when the moon comes
  between Earth and the sun and the SHADOW OF THE
  MOON FALLS ON PART OF THE EARTH
• Only occurs during NEW MOON PHASE

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SOLAR ECLIPSE - we see some portion of the Sun's
disk covered or 'eclipsed' by the Moon.
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Solar Eclipse
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Solar Eclipse

• During a total solar eclipse, the disk of the
  moon completely covers the disk of the sun.

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Total Solar Eclipse
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LUNAR ECLIPSE

• Happens when earth comes between the sun and the
  moon and THE SHADOW OF EARTH FALLS ON THE MOON
• Only occurs during FULL MOON PHASE
• Because the moons orbit is elliptical, the
  distance between the moon and the Earth changes

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Lunar Eclipse
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• The shadow of the Earth falls on the moon
• Which gives the moon a reddish tint

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Lunar Eclipse
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Annular Eclipse type of solar eclipse

• During an annular eclipse, the disk of the moon
  does not completely cover the sun
• During a total solar eclipse the disk of the moon
  does completely cover the sun only the corona
  is visible

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annular eclipse
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Total Solar Eclipse
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Orbit of the Moon

• The moons orbit around Earth is tilted about 5º
  relative to the orbit of Earth.
• This is why there arent solar and lunar eclipses
  every month

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Tilt of the Moons Orbit

• Tilt is enough to place the moon out of Earths
  shadow for most full moons and Earth out of the
  moons shadow for most new moons.