| For a good timeline of the development, see the late [1] Michael F. Flynn's "The Great Ptolemaic Smackdown"; table of contents: * https://tofspot.blogspot.com/2013/10/the-great-ptolemaic-sma... First evidence for Earth's motion: > 1728. Building on efforts by Flamsteed, Hooke, and others attempting to detect that old bugaboo, parallax, James Bradley detects stellar aberration [2] in γ-Draconis (Phil. Trans. Royal Soc., 1729). > A similar phenomenon appears when you drive through a snow storm. Even though the snow is falling straight down, it appears to originate at some point forward of your car. This is because as snow falls, your car is moving toward the snow. Similarly, as the starlight falls down the telescope tube, the telescope tube is moving with the earth and the light ray will hit the side of the tube instead of the eyepiece unless the telescope is tilted slightly. > The effect is small, and detectable only with special instruments, but it counts as a proof that the Earth is moving. * https://tofspot.blogspot.com/2013/10/9-great-ptolemaic-smack... Then for rotation: > Jun-Sep, 1791. In a series of experiments, Giovanni Guglielmini, a professor of mathematics at the University of Bologna, drops weights from the Torre dei Asinelli in Bologna -- the same tower used earlier by Riccioli and Grimaldi -- and finds an eastward (and southward) deflection. Concerned with windage, he repeats the experiment down the center of the spiral staircase at the Instituto della Scienze and finds a 4 mm Coriolis deflection over a 29 m drop; thus providing direct empirical evidence of the rotation of the Earth. These experiments are later confirmed in Germany (using a mine shaft) and in the United States. * Ibid Finally: > 1806. Giuseppi Calandrelli, director of the observatory at the Roman College publishes "Ozzervatione e riflessione sulla paralasse annua dall’alfa della Lira," reporting parallax in α-Lyrae. This provides a simple direct observation of the revolution of the Earth. > Keplerian heliocentrism had been accepted because it was computationally easier and because it popped out mathematically from Newton’s theory like Athena from the brow of Zeus. But now, finally, 263 years after Copernicus, the dual motions are established by empirical fact. Hot diggity. * Ibid Copernicus had an interesting idea, Galileo picked it up but didn't really add to it (though made improvements on telescope design), Kepler introduced a simplified mathematical model [3] (which just happened to be right) based on Tycho Brahe's observations. Stellar parallax has know about since at least Aristotle, and as he mentions in his On the Heavens (II.14), since it is not observed then it is reasonable to conclude that there is no motion (it took several thousand years to develop instruments to actually measure it). [1] https://news.ycombinator.com/item?id=37757574 [2] https://en.wikipedia.org/wiki/Aberration_(astronomy)#Discove... [3] There were actually seven models in contention at one point: https://tofspot.blogspot.com/2013/08/the-great-ptolemaic-sma... |