This Day in Tech History

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Ya mean we’re not the center of the Universe?

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April 26, 1514:  Copernicus Made His First Observations of Saturn

The ancient astronomers believed in the geocentric model of the Universe. The Earth was at the center of the Universe, and everything else orbited around it in crystal shells: the Sun, the Moon, the planets and the stars. One problem with this model was the strange movements of the planets. They would sometimes slow down, stop and even travel backwards in the sky. And to explain this, astronomers had to create elaborate models for the planets where the orbited inside spheres within spheres.

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Anyway, this model was turned on its ear by Nicolaus Copernicus in the 1500s. He placed the Sun at the center of the Solar System, and had all the planets orbiting around it. This nicely explained the strange movements of the planets. They weren’t going backwards, it was just a change in perspective, since the Earth is also going around the Sun.

The results of his observations of Mars and Saturn in this period, and especially a series of four observations of the Sun made in 1515, led to discovery of the variability of Earth’s eccentricity and of the movement of the solar apogee in relation to the fixed stars.

The publication of Copernicus’ book, De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), just before his death in 1543, is considered a major event in the history of science. It began the Copernican Revolution and contributed importantly to the rise of the ensuing Scientific Revolution.copuniv

Copernicus’ heliocentric system placed the Sun immobile at the center of the other planets in the [correct] order Mercury, Venus, Earth, Mars, Jupiter, Saturn.

Copernicus argued not only that the Earth moved, but also that it moved in two different ways – diurnal motion on its axis, and annual motion around the Sun.  WoW, what a concept!

Copernicus’ “Commentariolus” summarized his heliocentric theory.  It listed the “assumptions” upon which the theory was based as follows:

1. There is no one center of all the celestial circles or spheres.
2. The center of the earth is not the center of the universe, but only of gravity and of

the lunar sphere.
3. All the spheres revolve about the sun as their mid-point, and therefore the sun is the center of the universe.
4. The ratio of the earth’s distance from the sun to the height of the firmament (outermost celestial sphere containing the stars) is so much smaller than the ratio of the earth’s radius to its distance from the sun that the distance from the earth to the sun is imperceptible in comparison with the height of the firmament.
5. Whatever motion appears in the firmament arises not from any motion of the firmament, but from the earth’s motion. The earth together with its circumjacent elements performs a complete rotation on its fixed poles in a daily motion, while the firmament and highest heaven abide unchanged.
6. What appear to us as motions of the sun arise not from its motion but from the motion of the earth and our sphere, with which we revolve about the sun like any other planet. The earth has, then, more than one motion.
7. The apparent retrograde and direct motion of the planets arises not from their motion but from the earth’s. The motion of the earth alone, therefore, suffices to explain so many apparent inequalities in the heavens.”

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“There is talk of a new astrologer who wants to prove that the earth moves and goes round instead of the sky, sun and moon, just as if somebody moving in a carriage or ship might hold that he was sitting still and at rest while the earth and trees walked and moved. But that is how things are nowadays: when a man wishes to be clever he must needs invent something special, and the way he does it must needs be the best! That fool wants to turn the whole art of astronomy upside-down. However, as Holy Scripture tells us, so did Joshua bid the sun to stand still and not the earth”
Martin Luther on Copernicus.
 
Hubble_infrared_of_Saturn hs-2009-12-anim_lg inset-saturn-rings-large hst_saturn_storm Saturn_03

Computer-rendered image of Cassini-Huygens during the Saturn Orbit Insertion (SOI) manoeuvre

Computer-rendered image of Cassini-Huygens during the Saturn Orbit Insertion (SOI) manoeuvre

Saturns Beautiful Aurora

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