Penny System Model of Universe

People who visit the History of the Universe website sometimes say that the universe is so huge they find it impossible to imagine. The Penny System will help you to see the sizes of the main objects in the universe relative to the size of the Solar System. How does it work?

Imagine we could shrink the Solar System down to the size of a penny (or any other coin 2 cm in diameter).

Image of penny by *ade under a Creative Commons Licence
Let's take this penny to represent the entire Solar System.

Now you might think the Solar System just contains the planets Mercury, Mars and so on, but in fact it is much bigger than this.
The outermost part of our Solar System is the "Oort Cloud".
It is a spherical shell which lies very far from the Sun, containing billions of frozen rocky snowballs called comets.
In comparison with this, the orbits of even the outermost planets are tiny.

Now if we shrink the Solar System down to the size of a penny, it would look like this:

Notice how small the planetary region (shown in red) is in comparison to the penny.

Now let's see the size of some common universal objects compared to our penny Solar System.

Objects in the model

The map below shows the main objects in the universe on a map.
You can drag the objects to a new position.

Other Penny System Objects

Note that some things are too small to see on this map, and others are too big.
For the small things, visit this page.
For the large things, go to this page.

For the data upon which these pages are based see this spreadsheet

We give the details of the sizes of objects here.

Object (click for info)	Average Galaxy	Milky Way	Cluster of Galaxies	Small Void	Average Void
Icon
Light Years Across	30 thousand ly	100 thousand ly	3.3 million ly	36 million ly	160 million ly
Model Distance Across	38 000 cm	125 600 cm	4 100 000 cm	45 000 000 cm	200 000 000 cm
Click to Zoom
Example of Size	Large Ship	City Park	City	Island of Ireland	India
You can move any object to a new address. Enter the address here then press the Move button