SOLSYS.XLS - THE SCALE MODEL SOLAR SYSTEM SPREADSHEET
1998 – The Clark Foundation
The file SOLSYS.XLS is a spreadsheet that allows the user to calculate the scale sizes, distances from
the Sun, and velocities of the planets of our Solar System.
This spreadsheet will work on both Macintosh and PC computers using Microsoft Excel 4.0 or later.
UNITS of Measurement
Because sizes and distances in the model can change dramatically depending on how large or small a
model Earth you use, sizes and distances are calculated and displayed in a variety of units, both English
and metric. For example, if you make the scale model Earth very small, it will be easier to understand
distances in your model Solar System in meters. If you make your model Earth large, then kilometers or
miles are more useful measurements of scale distances.
THE REAL SOLAR SYSTEM
Rows 6-16, columns A through I, display the true diameters of the Sun, Moon, and Planets in kilometers
(B6-B16), miles (C6-C16), and Earth diameters (D6-D16).
Rows 7-16, columns E, F, and G, give the true average distances of the planets from the Sun in millions
of kilometers (“km^6”, cells E7-E16), millions of miles (“miles^6”, cells F7-F16), and Astronomical Units
(“A.U.”, cells G7-G16). One A.U. is the average distance between Earth and the Sun.
The periods of orbit (the time to complete one orbit) of the planets and Earth's Moon (around Earth) is
displayed in both years (cells H7-H16) and days (cells I7-I16).
CREATE A MODEL SOLAR SYSTEM
To use the spreadsheet, enter the diameter of the scale model Earth you want (in millimeters) into cell
M1. The spreadsheet will then calculate and display the following:
SCALE
The absolute scale of your new model Solar System is shown in cell M9. For example, entering “50” in
cell M1 (setting the size of your model Earth to 50 millimeters – about 2 inches) produces a scale of
1:255,120,000. This means that the sizes and distances in your model Solar System are about two
hundred fifty-five million times smaller than reality.
Cell L10 displays the equivalents for converting 1 millimeter of scale distance in your model into
kilometers of actual distance. Cell L11 displays the corresponding conversion between scale model
inches and actual miles.
SCALE DIAMETERS
After the size of the scale model Earth has been entered in cell M1 the spreadsheet calculates and
displays the scale diameters of the Sun and planets in millimeters (cells B21-B31), inches (cells
C21-C31), and feet (cells D21-D31).
SCALE DISTANCES
Scale distances between the Sun and each planet are displayed in meters (cells E22-E31), kilometers
(cells F22-F31), and miles (cells G22-G31).
The average scale distance between the Moon and Earth is displayed in cells L33-L36 in centimeters (cell
L33), inches (cell L34), meters (cell L35), and feet (cell L36).
SCALE ORBITAL SPEEDS
The scale speeds of the planets as they orbit the Sun are displayed in centimeters per hour (cells
L22-L31), and inches per hour (cells M22-M31).
The average scale speed of the Moon as it orbits Earth is given in millimeters per hour (cell L37), and
inches per hour (cell L38).
SCALE SPEED OF LIGHT
The scale speed of light is displayed in kilometers per hour (cell L13), miles per hour (cell L14), meters
per second, (cell L15) and feet per second (cell L16).
SCALE DISTANCE TO ALPHA CENTAURI
This spreadsheet helps the user understand that the planets of our Solar System are tiny compared to the
distances between them. Understanding how large the distance is between our Sun and our nearest
neighboring star, Alpha Centauri, makes our Solar System seem crowded by comparison. Scale
distances between the Sun and Alpha Centauri are displayed in kilometers (cell C34) and miles (cell
C35).
EXAMPLE MODEL
Entering "2.55" as the scale size of Earth (cell M1) creates a scale of approximately 1:5 billion (cell M9).
The model Solar System is now one five-billionth the size of the real Solar System. At this scale, one
millimeter in the model equals about 5,000 km (cell L10), and one inch equals about 79,000 miles (cell
L11).
At this scale the Sun’s diameter (cell B21) is about 280 mm (the size of a basketball), and is not quite 30
meters (~100 feet) from a 2.55 millimeter model Earth (cell B24) that is about the size of a small
peppercorn.
The Moon is about the size of a poppy-seed (cell B25) and is 3 inches (cell L34) from the
peppercorn-sized Earth.
At a scale of 1:5 billion, the peppercorn-sized Earth still takes a year to orbit the basketball-sized Sun at
just over 2 centimeters per hour (cell L24).
Jupiter is about the size of a cherry tomato (cells B27, C27, and D27) and is about 155 meters (cell E27)
from the Sun.
Shrinking the Solar System to a scale of 1:5 billion also creates a new scale speed of light that is 5 billion
times slower than the true speed of light (about 300,000 km/sec.) It takes light from the Sun about 8.3
minutes to reach Earth. Reducing the speed of light to the scale displayed in cell M9 creates a “scale
speed of light” (cells L13-L16) that is correct for the scale model Solar System.
Light from the scale model Sun still travels at a “scale” speed of 300,000 km per second, and will still
arrive at the scale model of the Earth in a little over 8 minutes. In this model Solar System, the Sun-Pluto
distance is reduced to just under 1,200 meters (cell E31), and the scale speed of light is proportionately
reduced to about six centimeters per second (cell L15).
With the Solar System shrunk so small that the Sun is shrunk to the size of a basketball, the distance to
the Sun's closest neighboring star, Alpha Centauri, is still greater than the distance between Salt Lake
City and London (cells C34 and C35).
Imagine a basketball-sized Sun 30 meters (100 feet) from a pepper-corn-sized Earth. Tiny Pluto, a
half-millimeter wide, lies nearly three-quarters of a mile (1.2 km) away. Between this scale model Solar
System and our next closest star is an expanse of five thousand miles (8,100 km) of emptiness. Similar
distances separate the other 100 billion stars in our galaxy.
Now you know why it’s called “space.”