For #spacetober_challenge day 29 prompt orbit: #mathematician and #astronomer Johannes Kepler (1571-1630)! We remember him for his role in the Scientific Revolution, and his three laws of planetary motion in particular. His laws modified Copernicus’ heliocentric model; he replaced the circular orbits with elliptical ones & described velocities of planets. Today we know them as:
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#sciart #histstm #Kepler #geometry #PlatonicSolids #mathematics #musicOfTheSpheres #linocut
1) Planetary orbits are ellipses with the Sun as one of the foci (top magenta ellipse)
2) A line from Sun to planet sweeps out equal areas in equal time periods (middle ellipse)
3) The square of the planet’s orbital period (or year) is proportional to the cube of the semi-major axis (shown as the horizontal arrow in the bottom ellipse).
But, I find it fascinating- & important to note- that he came to these laws exploring mystical ideas about music, geometry and congruence with physical 🧵2/
But this formula was not precise enough…. But we can see this as the seed of his 3rd law. The gold shapes are the nested Platonic solids from his Mysterium Cosmographicum - my example of form in #printmaking.
He also took the ancient idea of the “music of the spheres” literally and translated planetary angular speed as measured from the Sun as musical notes and finds that the minimum and maximum speeds of neighbouring planets approximate harmonies. 🧵4/5
Though unrelated to our modern ideas about our #solarSystem these explorations of geometry and music ultimately lead to his correct models, which in turn were a significant steps towards Newton’s Law of Universal Gravitation.
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Ele Willoughby, PhD