Monthly Archives: September 2013

A Grain of the Cosmic Ocean

If you put all the atoms which make up a single grain of sand next to each other, how long would the emerging line of atoms be?

Assuming that the diameter of a grain of sand is a fraction of a millimeter, our line would be some 1010 meters long.1

This is equivalent to the thirtyfold distance between the Earth and the moon or to the distance which light travels in vacuum in 33 seconds.
Furthermore, 1010 is approximately the number of 9 per cent of all people who ever lived or 3.3 per cent of the stars in our home galaxy, the Milky Way.

Sand from Kuta, Bali, Indonesia. (Credit: Renée Janssen)

Carl Sagan’s words in Cosmos are given a whole new meaning.

The surface of the Earth is the shore of the cosmic ocean. On this shore, we’ve learned most of what we know. Recently, we’ve waded a little way out, maybe ankle-deep, and the water seems inviting. Some part of our being knows this is where we came from. We long to return, and we can, because the cosmos is also within us. We’re made of star stuff. We are a way for the cosmos to know itself.

1 Jargodziki, Christopher / Potter, Franklin: Wie man ein Sandkorn zum Mond rollt. Physikalische Rätsel und Paradoxien, Stuttgart: RECLAM 2009

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