The Sun is the Size of your Eyeball
You are the center of the universe.
Well, at least you are for this scale model. You will be the Sun.
Imagine that the Sun shrank to the size of one of your eyeballs (about 24mm diameter) and it got placed inside your head. You are now the Sun, center of the solar system, looking out into the vast expanse of the solar system and space beyond.
Mercury is just 1 meter away – it is microscopic, essentially invisible at one tenth of a millimeter (0.1mm), the tiniest grain of sand. But if you reach out your arm and point your fingertip as far as it will go, you can almost touch it. Swing your arm around and you trace its orbit around your eyeball sun.
Venus is 1.86m (6ft) away – about the height of a tall-ish man. The second planet from your eyeball Sun is a little bit bigger than Mercury, but still almost invisible at the size of a single grain of fine sand (0.2mm).
Earth is 2.5m (8ft, 2in) away – just a bit farther away than Venus. You can’t reach it with your outstretched hand; you would have to take a step towards it. Earth is also a little bit bigger than Venus, but not by much. And at this scale, the Earth is just another fine grain of sand so it’s almost impossible to find anyway.
The Moon, smaller than Mercury, orbits just 0.6cm from the Earth sand. Imagine… your eyeball and two tiny grains of sand held in a 5m (16ft) diameter orbit.
Imagine all the empty space in the solar system. Imagine all humans on the surface of that Earth grain – and we have only visited the first 3 planets.
Mars is smaller than Earth and orbits 3.9m (12ft 10in) away. It is another grain of sand – with a red tint.
Jupiter is 13.4m (44ft) away. Imagine the outside length of a large school bus – that’s how far away Jupiter is. Jupiter is the first planet in this scale model that is visible – it is 2.5mm diameter – at this scale, Jupiter is about the size of a small peppercorn.
Saturn is 24.6m (about 81ft) distant. It has shrunk to the size of half a sprinkle. This sprinkle crumb is far enough away from your eyeball Sun that you probably couldn’t see it.
Uranus disappears at 0.8mm and 50m (162ft) away. It’s about the size of a small ant’s head.
Finally, we reach the similar-sized ant-head Neptune at 0.8mm which is an astonishing 77m (255ft) away at this scale. This is a bit closer than the entire length of a football field or a soccer pitch – Neptune would be at the other team’s 20 yard line or 18 yard line respectively.
Summary
Close your eyes. Imagine your eyeball is the Sun.
All these tiny objects are orbiting your head at different distances in a more-or-less flat plane.
Out. In. Space.
References
Thanks to Guy Ottewell for his insights into how to use everyday objects to communicate the scale of the solar system – especially his groundbreaking Earth as A Peppercorn.