24 December 2009


By now most people (hopefully) have seen the classic 1970s video Powers of Ten, which begins with an overhead view of a couple picnicking, zooms back (up). Every ten seconds the view is ten times farther away, and the field of view ten times wider, than the previous increment. This geometric progression from person to landscape to continent to planet to solar system to galaxy, culminates in what was then thought to be a view of the entire universe. Reversing the process, the virtual camera zooms back to the couple, and continues magnifying until reach the atomic level. The narration clarifies any ambiguity nicely.

Recently I discovered a variation on this video, The Known Universe, produced by the American Museum of Natural History. Computer animation is orders of magnitude more sophisticated, and no narration is needed, since visual labels appear at regular intervals. The zoom down to the cellular and atomic levels is not included.

Both videos are well worth watching, for a deeper understanding of the relativity of distance and the sheer vastness of space. I once read that if you were to place three grains of sand inside the largest cathedral on Earth, the ratio of matter to empty space would approximate that found in the universe, or in an atom. This was before the discovery of dark matter, but the analogy is still illuminating.
[FOOTNOTE, dated 21 Jan 2010: I actually scooped NASA in posting AMNH's The Known Universe video -- the APOD post appeared today.]

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