IAU00038
Presentation type requested: EITHER
MAPS OF THE COSMOS THROUGH 3600 YEARS
(danish ø, or hoeg) Erik Høg
Copenhagen University Observatory
The first known map of the Cosmos shows the Sun, Moon and stars in gold on a recently discovered disk from the early bronze age. Greek astronomers determined a correct size of the Earth and the distance to the Moon, but they got the distance to the Sun 20 times too small. Ptolemaios derived a radius of 20 000 earth radii for the sphere of fixed stars. This radius of the visible Cosmos at that time happens to be equal to the true distance of the Sun, or 14 micro-light-years. These distances stood unchallenged for the next 1500 years, including Tycho Brahe. Kepler was the first to doubt the solar distance. Today the radius of the visible Universe is a million billion (10 to the power 15) times larger than Tycho Brahe believed.
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