Everyday Science
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Everyday Science

The Solar System Is Made Of… Nothing

Distances in space are much bigger than we usually think

The image of the Solar System we are all used to seeing | Picture by Comfreak on Pixabay

Open your high school astronomy textbook: probably there is a picture of the Solar System showing the planets aligned and close together like the beads in a string (Pluto we miss you!).

That is for sure a nice picture, useful for showing all the planets, but a misleading one too. Planets are very, very, very far apart one to each other, and the Solar System is essentially, well, empty space.

One thing difficult to grasp when thinking of the Universe is how HUGE it is, and also in our Solar System, nothing more than our backyard, astronomically speaking, distances are so big that is almost impossible to understand them compared to our everyday experience.

Even the Moon, the closest astronomical object clearly visible from the Earth with bare eyes, is 385 000 km (240 000 miles) apart on average, that is around 100 times the distance by car between Venice in Italy and North Cape in Norway or, if you are American, between New York City and Phoenix, AZ.

And what about the rest of the planets? Let’s take a look.

Distance from the sun (km)

on average, planets orbit are elliptic.

Mercury: 58 000 000
Venus: 108 000 000
Earth: 150 000 000
Mars: 228 000 000
Jupiter: 778 330 000
Saturn: 1 427 000 000
Uranus: 3 000 000 000
Neptune: 4 470 000 000

As you can see, distances range from almost 60 million of kilometers for Mercury to billions of km for outer planets, like Saturn, Uranus and Neptune.

Wow, those are big numbers, and so? So almost nobody could really figure them. So let’s put everything in a more understandable scale.

Imagine to shrink the Earth to the size of a golf ball, i.e. 4.3 centimeters in diameter, and scale all the other planets accordingly. Then take the Sun, that now is a sphere 4.7 meters wide, and place it on the Alice in Wonderland statue in Central Park, New York.

Going on with this game we have to place the planets in the correct order at the right scaled down distance. So, in our miniaturized Solar System, Mercury, the closest to the sun planet, falls at 196 meters from the Sun, nearby to Trefoil Arch.

Venus, a little bit smaller than our golf ball-sized Earth is 364 meters apart from the Sun, in Rumsey Playfield; Earth, now 4.3 centimeters wide stays at 506 meters, in Literary Walk, and Mars is placed near Shakespeare Statue, 769 meters from the Sun.

Distance between planets of the inner Solar System when we scale it down as the Earth is the size of a golf ball compared to NY City map | Picture created by the author using Google MyMaps.

All the scaled-down inner Solar System is contained within Central Park, but in reality the space between the planets is essentially void, apart from tiny bits of rocks and cosmic powder.

Going on with the model, distances become larger even in this tiny version of Solar System: Jupiter is as big as a beach balloon located near Times Square (2.62 kilometers from Alice Statue), Saturn in Union Square Park (4.81 kilometers), Uranus is like a handball in Liberty State Park (10.11 kilometers) and Neptune far away in New Jersey, near Cape Liberty Cruise Port.

Distance between planets of the whole Solar System when we scale it down as the Earth is the size of a golf ball compared to NY City map | Picture created by the author using Google MyMaps.

So think of it for a while: if we shrink the Solar System so the Earth is as tiny as a golf ball, the scaled down distance between Sun and the farthest planet is around 15 kilometers. And keep in mind that the space between planets is almost filled with nothing!

Quite a big difference from the bead-string picture we are used to seeing.

Something to listen

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Diego Tonini

Diego Tonini

Writer and science communication enthusiast, I think science can be fun and everyone can understand it!