Sunday, December 20, 2009

The Known Universe in Six Minutes

The American Museum of Natural History has updated one of my favourite movies with their presentation of The Known Universe (suggestion - use the Fullscreen button which is the second button brom the right on the Youtube playback bar):

The Known Universe movie is based on visualization of current astronomical and astrophysical data which the American Museum of Natural History maintains through the affiliated Hayden Planetarium as part of its Digital Universe Atlas.

The favourite movie that I referred to earlier is Powers of Ten, made by Charles and Ray Eames in the 1970s. For many years, the film made as a proposal (in the late 1960s) for the final Powers of Ten film was shown in the Ontario Science Centre.

The final Powers of Ten film is a short documentary, lasting under ten minutes. Narrated by Philip Morrison, it has what I think of as a cosmic part and a quantum part. The cosmic part zooms out from a height of one meter above a couple at a picnic. Every ten seconds, the scale increases by a factor of ten. At one hundred million light years, the perspective is reversed back to the starting point one meter above the couple. At that point, the scale zooms inward, until it ends up focused on the nucleus of a carbon atom in the hand of one of the picnickers. Forty orders of magnitude are covered, and in a very compact way, the movie shows the continuity of the physical world from everyday experience to both the cosmic and quantum.

Unlike Powers of Ten, The Known Universe does not stop at 100 million light years, but instead goes all the way out to the horizon of the known universe at 13.7 billion light years -- two and a fraction orders of magnitude farther out.

Those extra orders of magnitude are due to the advances in the 32 years between the two films. The work that had been done by Allan Sandage in calibrating the cosmic distance scale had allowed distances to be derived for galaxies out to 25 and 50 million light years with objects like M100 and M101 in the 70s and 80s, more tentatively for objects at greater distances. For the state of the art in 1977, 100 million light years was a pretty substantial distance.

The revolution in available data and knowledge that came with the advent of the Hubble Space Telescope, the other Great Observatories space missions, and COBE, allowed the distance scale and the Hubble Constant to be much more firmly nailed down, and this in turn made possible the truly awesome visualization that the AMNH has done.

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