Imagine the earth would be reduced in size to a small shpere with a diameter of 1 mm. What would be the diameter of the sun? How far would it be away from the earth? What would be the equivalent of one lightyear? What would be the distance between the earth and the next star Proxima Century? And so on. This app gives you an idea of these dimensions. The model dimension is shown on a map, if big enough, as a reddish semi-transparent circle around your location! Have fun!