How Far?


My reaction to this number line is one of awe, both at how many orders of magnitude nature has used, and at what a narrow range of objects are familiar to me. This past summer I looked in the sky at the Andromeda galaxy. It seems to be almost the size of the moon, but it is 2,000,000 light years away. Just the idea of so large an object fills me with awe and admiration.

This chart probably extends further in both directions. There is no known end either way. There are clusters of clusters of galaxies, and theoretical phcists are speculating on the nature of space and time at a scale called the Planck length, about 10^-32 meters.