1. Sun-Earth-Moon Relationships
Journey into Space
Journey Museum, July 18-20, 2012
Modified from
Rick Varner, AESP
Goddard Space Flight Center
Greenbelt, MD

2. Aristarchus of Samos Early Scientists’ Work Acropolis
The Greeks were perhaps the first to study our satellite scientifically. Using Earth's shadow on the moon during lunar eclipses as a guide, the third-century B.C. astronomer Aristarchus estimated it lay 60 Earth radii away. (It was a remarkable guess: in fact, the distance varies between 55 and 63 Earth radii, or 220,000 and 250,000 miles.)
The moon receives its light from the sun.
2) The earth is positioned as a point in the center of the sphere in which the moon moves
3) We see half of the moon

3. How Far Away is the Moon? ~ 384,000 km Too Far Away For a Ruler!
Average Distance: Metric: 384,400 km English: 238,855 miles
Perigee: Metric: 363,300 km English: 225,700 miles
Apogee: Metric: 405,500 km English: 252,000 miles
Moon Equatorial Circumference: Metric: 10,916 km English: 6,783 miles
Earth Equatorial Circumference: Metric: 40,075 km English: 24,901 miles
Average Distance 384,400 km (~240,000 mi)

4. Let’s use a distance that we already know to develop our model!
~13,000 km
Mathematics
Earth 12,756 km diameter (6,378.14km radius) Moon 3,475 km Diameter ( km radius)
384,000 km =
30 (29.54)
13,000 km
Earth’s diameter = 12,756 km (rounded 13,000 km)
Moon’s diameter = 3,475 km (slightly more than ¼ the of Earth)

5. The Model
The Moon is approximately one fourth the diameter of the Earth. 1” and ¼” craft beads can be used to simulate the Earth & Moon.
Clipped to a yard stick 30” apart creates a mobile model that can used for both distance and eclipse simulations.
Since this is a rounded measurement, the actual distance is from bead surface to bead surface.

6. Earth to Moon Scale Modeling Variations: Age/Developmentally Appropriate Audiences
Pre-existing Models: Replogle Small Lunar Globe
12” Earth Globe
Athletic Balls: Basket Ball & Tennis/Baseball Ball
Painting, Drawing, Clay, Play-Dough, etc…
Balloons: Blue Round - Earth
White Round - Moon, Red Balloon?
Mathematical Models: using only numerical
measurements

7. Diameter Approximate Scale Models
~24 cm
6.9 cm
The “Moon ABCs Fact Sheet” lists the Earth's diameter as 12,756 km and the Moon's diameter as 3,476 km
Therefore, the Moon's diameter is 27.25% of Earth's diameter. An official basketball has a diameter of 24 cm. This can serve as a model for Earth. A tennis ball has a diameter of 6.9 cm which is close to 27.25% of the basketball. (The tennis ball is actually 28.8% the size of the basketball.)
Earth 12,756 km diameter (6,378.14km radius) Moon 3,475 km Diameter ( km radius)
Earth Moon
12,756 km ,476 km

8. The Phases of the Moon

9. Protect eyes from direct viewing of the sun.
Moon Phase Modeling
Ping Pong Ball
Hot Glue
Long Golf Tee
Glue the ping pong ball to the golf tee with the company logo covered by the top of the golf tee.
If the moon is visible, hold the ball at arm’s length below the moon and compare.
Rotate counterclockwise to simulate lunar phases
Protect eyes from direct viewing of the sun.

10. Ping Pong Ball
Lunar Model

11. http://aa.usno.navy.mil/data/docs/RS_OneDay.php 3 4 2 5 1 6 8 7 1 2 3
6/11/12
6:42am
50%
Plate Activity 3
6/8/12
4:48am
77%
6/16/12
10:49am 8% 4 2
The Sun is VERY far away!
6 a.m.
6/19/12
11:03am
9 a.m.
3 a.m.
6/4/12
12:52am
12 p.m. Noon
12 a.m Midnight 5 1
3 p.m.
9 p.m.
6/2/12
11:49pm
95%
6/20/12
2:04pm 1%
6 p.m. 6 8 7 1 2 3 4 5 6 7 8

12. Antonio Cidadao: http://www. usno. navy

13. The Model
Eclipses

14. Use the sidewalk or a flat surface to align the shadows.
Look at the shadows on the background, then look at the beads.
Sun • Moon • Earth = Solar Eclipse
Sun • Earth • Moon = Lunar Eclipse

15. August 11, 1999 Solar Eclipse viewed from Mir

16. May 20, 2012
Terra Spacecraft

17. December 20, 2010
Lunar Eclipse

18. Connecting the Lunar Phases to the Solar & Lunar Eclipse

19. Sky & Telescope Article on 2010 Eclipses:

21. http://www.mreclipse.com/Special/SEprimer.html Aug 21, 2017
Next total solar eclipse…visible in the U.S. from SC to OR