Earth, Sun, and Moon

1
Earth, Sun, and Moon
2
Physical Properties of Earth

• Diameter (pole to pole) 12,714 km
• Diameter (equator) 12,756 km
• Circumference (poles) 40,008 km
• Circumference (equator) 40,075 km
• Mass 5.98 x 1027 g
• Density 5.52 g/cm3
• Average distance to sun 149,600,000 km
• Period of Rotation 23 hr 56 min
• Period of Revolution 365 days 6 hr 9 min

3
Motions of the Earth

• Rotation
• Turning or spinning on its axis
• Revolution
• Earth revolving around the sun in an elliptical
  orbit
• Precession
• Slight movement over a period of 26,000 years of
  Earths axis

4
Rotation

• 2 ways of measuring
• 1) Solar Day time from one noon to the next
• 2) Sidereal Day- time it takes Earth to complete
  one full rotation (360 degrees) with respect to
  another star other than our sun
• Time required for a star to reappear at the
  identical position in the sky where it was
  observed the day before
• 23 hours 56 minutes

5
Revolution

• Earth revolves around the sun in an elliptical
  orbit at an average speed of 107,000
  kilometers/hour
• Average distance from the sun is 150 million
  kilometers
• Perihelion- Earth is closest to the sun 147
  million kilometers away (January)
• Aphelion- Earth is farthest from the sun about
  152 million kilometers away (July)

6
(No Transcript)
7
Precession

• Earth wobbles on its 23.5o axis and North pole
  points to different stars in 26,000 year period
• Now points towards Polaris
• In 14,000 will point to Vega
• By 28,000 will point to Polaris again
• Has a slight affect on seasons

8
Seasons

• The northern hemisphere experiences summer when
  Earth is farthest from the sun.
• It experiences winter when Earth is closest to
  the sun.
• The seasons are a result of the Earths tilt on
  its axis.
• Remember Earths axis is at a 23.5o tilt.

9
(No Transcript)
10
Equinox

• Equinox is the time when the sun is directly on
  Earths equator.
• Number of daytime hours Number of nighttime
  hours
• Northern and Southern Hemispheres are not tilted
  toward the sun.
• Spring Equinox Around March 20, 21
• Fall Equinox September 22, 23

11
Solstice

• The point when the sun reaches its greatest
  distance north or south of the equator.
• Summer Solstice June 21, 22
• Long days, shorter nights
• Winter Solstice December 21, 22
• Short days, longer nights
• http//esminfo.prenhall.com/science/geoanimations/
  animations/01_EarthSun_E2.html

12
Earth-Sun Motion

• Earth, Sun, and solar system speeds in the
  direction of the bright star Vega at 20
  Kilometers per second
• Also- Sun revolves around the galaxy
• Galaxies themselves are also in motion
• We are approaching Andromeda

13
Earths Moon (Luna)

• Earths only natural satellite (objects that are
  in Earths orbit)
• Density is 3.3X greater than mantle rocks of
  Earth
• Gravitational attraction is 1/6 of that on Earth-
  150lb on Earth 25 lb on the moon

14
Earths Moon

• The moon rotates on its axis, and revolves around
  the earth.
• Moons rotations 1 rotation every 27.3 days
• Moons revolution 1 rev. every 27.3 days
• Because the revolution and rotation times are the
  same, we always see the same side of the moon.
• The moon shines because of light being reflected
  from the sun.
• Moon phases are the changing appearances of the
  moon as seen from Earth.

15
Phases of the Moon

• New Moon the lighted half of the moon is facing
  the sun and dark side faces the earth.
• Occurs when the moon is between Earth and the
  sun.
• Waxing Shortly after the new moon, more and
  more of the moons lighted side becomes visible
  (about 24 hours after new moon)
• Waxing occurs until we see the full moon

16
Waning Phases

• Happens after the full moon, when the moons
  lighted side becomes smaller.
• Waning gibbous occurs after the full moon.
• Then third quarter phase occurs
• Next comes waning crescent
• Finally the waning phase ends with a new moon.

17
(No Transcript)
18
New Moon
19
Waxing Crescent(Anything small than a quarter)
20
First Quarter
21
Waxing Gibbous(More than one-quarter is visible)
22
Full Moon
23
Names for the Full Moon

• January Wolf or Hunger moon. During this month
  the wolves once roamed the countryside, thus
  suggesting the name wolf moon. In cold and
  temperate climates of the Northern Hemisphere, it
  was difficult to find food during January, thus
  the name hunger moon.
• February Snow Moon. In certain parts of the
  world, snow is usually the deepest in this month,
  thus the name snow moon.
• March Sap or Worm Moon. Because sap rises in
  March, this full moon is called the sap moon. The
  ground softens during this month, and worms begin
  to burrow out of the ground, thus the name worm
  moon.
• April Pink Moon. Many flowers turn pink and
  bloom in April, thus the name pink moon.
• May Flower Moon. Because many flowers bloom in
  May, after the April downpours, May's moon is
  called the flower moon.
• June Strawberry or Rose Moon. Because
  strawberries bloom in June, this month's moon is
  the strawberry moon. Also, the French call this
  moon la lune rose, which translates into English
  as "the rose moon."  

24
Names for the Full Moon Continued

• July Buck Moon. Male deer, or bucks, grow their
  first antlers during this month, thus the name
  buck moon.
• August Sturgeon Moon. Because it is sturgeon
  season in certain parts of the world in August,
  its moon is called the sturgeon moon
• September Harvest or Corn Moon. Native Americans
  began to harvest their crops during this month
  every year. (If this full moon occurs late in
  August it is called the harvest moon.). If the
  full moon occurs earlier in September, it is
  called the corn moon because the corn crop is
  ready for picking at that time.
• October Hunter's Moon. The hunting season begins
  in October, thus the name hunter's moon.
• November Beaver Moon. Beaver traps were once set
  in this month to catch enough beaver to make warm
  clothing for the upcoming winter.
• December Cold Moon. The approach of cold weather
  in the Northern Hemisphere gives this month's
  full moon its name. Compton's Interactive
  Encyclopedia

25
Waning Gibbous
26
Third (Last) Quarter
27
Waning Crescent
28
New Moon(Cycle starts over again!!!)
29
Eclipses

• Shadow effects
• When the moon moves in a line directly between
  Earth and the Sun it casts a shadow on Earth-
  Solar Eclipse
• When the moon moves within Earths shadow- Lunar
  Eclipse
• The revolution of the moon causes eclipses
• What does the moon revolve around?

30
Solar Eclipses

• Umbra Darkest portion of the moons shadow
  (Total Eclipse)
• Penumbra Surrounds the umbra and is lighter
  shadow on Earths surface (Partial Eclipse)

31

• Caution Regardless of where you are standing,
  never look directly at a solar eclipse. The
  light will permanently damage your eyes.

32
(No Transcript)
33
(No Transcript)
34
Lunar Eclipse

• Happens when the shadow of Earth falls on the
  moon.

35

• Moon moves into Earths penumbra.
• Continues to move, enters the umbra, and you see
  a curved shadow on the moons surface.

36
Partial Lunar EclipseOnly a portion of the moon
moves into Earths umbra
37
Total Lunar Eclipse(January 2000)
38
Structure of the Moon

• Dont believe everything you read.
• Discovery of life on the Moon was announced to
  the American public by the New York Sun in 1835.
  This fanciful illustration is supposed to have
  shown what astronomers were seeing with new and
  more powerful telescopes.

39
(No Transcript)
40
Structures of the Moon

• Maria are dark-colored, relatively flat regions
  on the moon.
• Formed when ancient lava flows from the moons
  interior filled large basins on the moons
  surface.
• Some are 3 to 4 Billion years old and are the
  youngest rocks on the moon
• Highlands- densely pitted light-colored areas
• Regolith- soil-like layer composted of igneous
  rock, glass beads, and fine lunar dust

41
Maria
Maria
42
Craters

• Most obvious features on the moon
• Depression formed by meteorites, asteroids, and
  comets, which struck the moon.
• Cracks have formed in the moon, during impacts
• Many more than Earth because the moon has no
  atmosphere to burn up debris and no destruction
  by tectonic forces

43
South Pole of the Moon
44
Surface seen by Apollo 11 on its decent to the
moon
45
Apollo 11
46
(No Transcript)
47
Moon Interior
Core
Mantle
Crust
48
Moons Interior

• Earthquakes allow scientists to map the moons
  interior.
• Seismographs were left by Apollo astronauts
• Crust
• 60 km thick on the side facing Earth
• 150 km thick on the far side
• Mantle solid mantle, maybe 1000 km thick
• Core May be a solid iron-rich core

49
False Color MosaicTaken by Galileo in 1992
Red Lunar Highland Blue Orange ancient lava
flows Blue regions contain more titanium than
orange Purple regions that formed during large
volcanic eruptions
50
Moon dust under microscope
Mostly titanium and iron oxides
51
Origins of the Moon

• Three popular theories, prior to the Apollo
  missions
• Moon was captured by Earths gravity
• Moon condensed from loose material surrounding
  Earth during the formation of the solar system.
• Blob of molten material was ejected from Earth
  while Earth was still in its early stage.

52
Impact Theory
53
Impact Theory

• Moon formed around 4.6 billion years ago when a
  Mars-sized object collided with Earth
• Melted part of Earths Mantle and the impacting
  object. Material ejected into space
• Debris started orbiting the Earth, some debris
  fell back to Earth
• Material formed a ring of hot dust and gas around
  Earth
• In about 100 years, the particles in the ring
  joined together forming the moon

54
(No Transcript)
55
Future Moon Missions

• Will there be future missions to the moon?
• Will there be colonies on the moon?
• How can we sustain life on the moon?
• Please take a few moments to think about these
  questions.