The Moon

1
The Moon

• It may sound goofy, but the Man-in-the-Moons a
  Newfie
• Stompin Tom Connors

2
The Moons Influence (?)
3
Lunar Mythology

• Crime rates, birth rates, lunacy and accidents
• Visit http//skepdic.com/fullmoon.html
• The big moon explained
• The travelling moon

4
Earth and Moon

5

• Eclipses

6
Consequences of Eclipses

• Predictability and Columbuss use!

7
More Mundane MattersThe Distance and Size of
the Moon

• If we knew how far away the moon is, we could
  calculate how big it really is!
• or
• If we knew how big the moon really is, we could
  calculate how far away it is!

8
A Low Precision Method

• Rely on assumptions about shadow sizes
• If the Earths shadow swallows up the moon, is
  the Earth bigger than the moon?
• Can we use and quantify this?

9
Big Shadows
10
But Consider
11
Conclusion?

• The Earth is several times as big across as the
  Moon.

12
Instead, Consider Binocular Vision!

• Watch the experiment run in class.
• Can this help in astronomy?

13
YES! We Use Parallax Measurements

• Alternative word triangulation. (Consider the
  word triangle. )
• Think of a surveyor.

14
Objects in the Sky

• Q1 How do you work out the height of clouds? Or
  the ceiling of Theatre D?
• Q2 Consider the noisy helicopter

15
Essential Ingredients

• Both observations must made at the same time!
  (unless the target is known not to move)
• We need two widely-spaced locations, with a known
  separation.
• We need a reference frame for measuring the
  angles. (Easy on small scales, but remember that
  the Earth is curved!)

16
Where Do We See the Moon with respect to the
Background Stars?
17
The Moon at 1100 PM on Oct 29as seen from
Kingston (left) and Santiago, Chile (right)
18
For the Moon?

• Could the ancients have done this?
• - some practical problems

19
Modern Distance Determinations

• Go there, and keep track of speed and time.
  (Apollo astronauts, space probes)
• Bounce radar or visible light off the surface,
  and see how long it takes to go there and back.
  Very precise!

20
Lunar Laser Reflectors
21
Limitations!

• These work only inside the Solar System! There
  is no practical travel or use of radar beyond.
• (Why not?)