 | Nicolaus Copernicus
Polish astronomer, mathematician, and canon
Modeled the movements of the Sun, the Moon, and the five known planets in the skies above, using a heliocentric system of orbits.
Born: 1473 in Torun, Poland
Died: 1543 in Frombork, Poland |
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| An illustrationof the heliocentric model of the solar system, from the Harmonia Macrocosmica star atlas of Dutch-German cartographer Andreas Cellarius, circa 1660. |
Tycho Brahe (1546 – 1601) developed a comprehensive method of recording precise observations of the skies, before the advent of the telescope. His many detailed observations included:
- the discovery of a supernova (a new star, to all appearances, which shone brightly and then faded away) in the heavens, in 1572
- measurements of parallax for comets, showing that they were further away than the Moon
- extensive measurements of the position of Mars in the skies; these data led in time to Kepler's three laws of planetary motion
- the most detailed measurements of stellar parallax to date, which still showed no effect
Tycho proposed an intermediate model of the universe, where the Earth was still the center point, but the other planets were allowed to rotate around the Sun as it rotated around the Earth. This was an intermediate solution, designed to explain the observational evidence that the planets moved around the Sun while preserving the sacrosanct notion that the Earth was the center of the Universe. Copernicus was willing to move one step further away from orthodoxy. By removing the Earth from its central position he freed the orbital paths of the planets from the extremely convoluted models of the Ptolmeic system, paving the way for Kepler's laws of elegant symmetry.
