Visualizing Your Place in the Solar System in Proper Scale

“Space is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space.”

– Douglas Adams, The Hitchhiker’s Guide to the Galaxy

Earth is home. Our Solar System is also home, but it is far larger than most people realize. Part of this is an inability to experience this distance in person: most people never spend much time traveling across the planet Earth in a way to take in the size of all our continents and seas, and our local backyard in outer space is orders of magnitude larger. Another problem can be the way space is presented to our visual minds in scale.

Often times you may see pictures of the Solar System that show all the planets close to each other, in relative sizes (but not accurate distances), like this:

solar system - scale sizes

(Do note that the first big things that draw your eye, Jupiter and Saturn, are not where you live. The barely illuminated pale blue smudge on the left is the whole Earth.)

Or this:

solar system - scale sizes 2

Alternatively you may see pictures of the Solar System that show all the planets spread out, in relative distances (but not accurate sizes), like this:

solar system - scale distances

What you very rarely see, because of the difficulty in presenting them, are pictures or models that show the Solar System in both scale distance and size at the same time.

One way to do this physically, as I have done in the past, is to find a long walkway, such as a hallway or field, and place markers every so often to indicate where the planets are, and a print-out of pictures showing the planets to scale at those sizes.

While I can (and later will) provide the usual examples (“at this scale, the Earth would be as small as a grain of sand,” etc.), what I want to do is give you the method, so that no matter where you are, whether you are by yourself, with your children or students, or with your peers, you can extend out the Solar System that scales to your location.

The first step is to have a location in mind. For the sake of an example, let us say you have the length of a football (soccer) field to place these planets on for your scale model. We know that, according to Wikipedia, a standard FIFA football pitch is 105 meters long from one side to the other the long way. We also know from NASA that Neptune is about 4,500,000,000 kilometers from the Sun, so we know how long the Solar System is from one side to the other.

(If you want to include Pluto, Ceres, Haumea, or other dwarf planets and objects, it may make things more complicated, so for this example I’m only going to use the standard 8-planet model.) This means you or I can plant a marker for the Sun at one end of the 105 meter field and a marker for Neptune at the other end.

“But,” one might ask, “where to put the other planets?” Well, consider that out of that 4½ billion km distance, the planet Mercury is 57,900,000 km from the Sun. With some simple calculation (dividing Mercury’s distance from the Sun by the total distance to the edge of the Solar System, 57,900,000 km ÷ 4,500,000,000 km), we can determine that Mercury is about 1.29% of the distance along the Solar System’s length (also the field’s length). If we multiply the field’s length by this percentage (105 m × 1.29%) I know that 1.35 meters from the Sun/beginning side of the field is where I can/should put my marker for the planet Mercury. In repeating this process, you can get a list of how far the planets are down the field, like so:

Body

Mean Distance (km)

% of Total Distance

Meters

Sun

0

0.00%

0.00 (the starting side)

Mercury

57,900,000

1.29%

1.35

Venus

108,200,000

2.40%

2.52

Earth

149,600,000

3.32%

3.49

Mars

227,900,000

5.06%

5.32

Jupiter

778,400,000

17.30%

18.16

Saturn

1,400,000,000

31.11%

32.67

Uranus

2,870,000,000

63.78%

66.97

Neptune

4,500,000,000

100.00%

105.00 (the ending side)

You can use meter sticks, but I recommend a trundle wheel for the outer planets.

Well, we’ve covered scale distance nicely, but what about size? Here we continue to calculate spaces relative to the distance between the Sun and Neptune, but now we are interested in the planets’ diameters, rather than their distance from the Sun.

Let’s use Jupiter as an example: On our 105 meter-long football field scale model, how large would the planet Jupiter be?

Jupiter’s diameter is about 140,000 km (give or take). With some more of that simple calculation (dividing Jupiter’s diameter by the total distance to the edge of the Solar System, 140,000 km ÷ 4,500,000,000 km), we can determine that Jupiter is about 0.003% of the distance along the Solar System’s length (also the field’s length). If we multiply the field’s length by this percentage (105 m × 0.003%) I know that Jupiter’s size on this scale is 4.66mm. In repeating this process, you can get a list of how large the planets are on this scale model, like so:

Body

Body Diameter (km)

% of Total Distance

Millimeters

Sun

1,392,684

0.03095%

46.4228

Mercury

4879.4

0.00011%

0.1626

Venus

12092

0.00027%

0.4031

Earth

12742

0.00028%

0.4247

Mars

6772.4

0.00015%

0.2257

Jupiter

139822

0.00311%

4.6607

Saturn

114632

0.00255%

3.8211

Uranus

50532

0.00112%

1.6844

Neptune

49105

0.00109%

1.6368

Get out a ruler and look: Millimeters are small, so something like Jupiter on this scale is very little, about as wide as the cap on the end of your shoelace. Again, Earth, where you live, is not the next size smaller down the list: that rank goes to Saturn, then Uranus, then Neptune. Earth comes in at less than one-half of a single millimeter on this scale.

When you set up that field with all the planets in a line, remember two things: first, that this 0.4 mm-wide speck of the planet Earth, near the size of a single pixel on a computer screen, is where the whole planet is. Singapore, sea lions, sectarianism, ice cream, and our species are all contained, confined, on that pixel, and nowhere else on the 105 meter field. The next pixel over, Earth’s moon, is the farthest any living human has explored, and the human race hasn’t been back since 1972, preferring the much closer low-Earth orbit zone instead. Second, the field assumes that all our planets are lined up for our convenience in arrangement and comparison, but this radial arrangement of our circular Solar System almost never occurs, meaning the diameter, area and volume of our Solar System is many times greater. Mars and Earth may be on opposite sides of the Sun far apart from each other, and as Mercury flies around its quick orbit, it can take decades for a single orbit of one of the outer planets flung wide in distance space.

Please set up this model for yourself, and for those you know and want the share this with. Try to visualize your place in the Solar System in proper scale. When I did this I was awestruck by realizing where I am, where all of us are, in just this one little spot in the universe.

Oh, and one last thing, for you fans out there of exoplanets and the idea of traveling the stars: Alpha Centauri is the next closest star system outside Earth. On the scale of the 105 meter field, to reach that system you would have to walk 950 kilometers away; this is farther than the distance between Cincinnati, Ohio and New York City (or between Brussels, Belgium and Vienna, Austria; or between Beijing, PRC and Seoul, South Korea).

That’s the next closest star system; they get much farther from there.

Feel free to message me or leave a comment response if my math is off: I’d rather all of us know what’s accurate than to just assume I’m right.

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