Astronomy Question of the Week: How far is ’unimaginably far’?

We often speak of 'astronomically high prices' –" 'astronomic' is a common way of describing anything that is extremely large. As a matter of fact, units of measurement are used in the field of astronomy that are far greater than the scale we are used to in everyday life. The nearest star –" Proxima Centauri –" is around 40,000,000,000,000 kilometres away. This example already shows that the unit of length that we are familiar with, the (kilo-) metre, is completely unsuitable for describing distances in the Universe –" but what units are more suitable?

http://www.dlr.de/en/desktopdefault.aspx/tabid-1/86_read-19637/