History of the Universe

History of the Universe eBook. 398 pages, 300 illustrations only £5.99

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Large and Small Objects

One of the insights we gain from following this story is that a human is about half-way in size between the very largest things in the Universe (clusters of galaxies) and the very smallest (particles). Grasping the size of these things is extremely difficult for us, so I have devised some ways to do it.


Soccearth is a way of getting an idea of the sizes of very small things relative to each other. Imagine a soccer ball blown up to the size of the Earth. What would it look like? We would be able to see the atoms and molecules which make up the ball.

The Earth's diameter is about 12,756 km. A soccer ball's is about 24 cm. The soccer ball must be blown up about 50 million times bigger to reach the size of the Earth. This is the Soccearth scale. In this story I will sometimes refer to Soccearth to convey the size of small things.

On this scale, an atom would be about 10 millimeters across - about the size of a large pea, a molecule such as an enzyme would be about the size of a refrigerator. We could see the bacteria and other cells which live on the soccer ball's surface. A bacterium would be about the size of an industrial unit or warehouse, 50 meters long.

But please note that even on this scale, the smallest things (particles) will still be too small to be visible.


In order to get a feeling for the largest things in the Universe, I use a model I call PennySystem. Imagine you could shrink the Solar System down to the size of a penny (or any disc 20 mm or 0.79 inches across). Then astronomical objects would shrink to a size we could understand.

The average distance between stars would be about 8.25 cm (3.25 inches), an average galaxy would be about 760 m (about half a mile) across and galaxies would be arranged in clusters about 83 km (51 miles) across. I give more examples throughout this story of the use of the PennySystem.

You can see a model of all the main objects in the universe superimposed on a map of the world at the Penny System Website

Note that in the PennySystem scale, 1 meter represents about 39.53 light-years, that is, the distance that light would travel in 39.53 years.

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History of the Universe eBook
History of the Universe eBook
Only £5.99

Written by Wyken Seagrave
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