The History of Astronomy Simplified on Superphysics

The System of Concentric Spheres

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Of all natural phenomena, mankind has been most curious of the celestial ones because of their:

greatness and
beauty

Those who surveyed the heavens found 3 sorts of objects:

The Sun
The Moon
The Stars

The stars appear always in the same place and at the same distance with regard to one another.

The Flat Earth; Increase of Spheres; Eccentric Spheres

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Flat Earth

Before the Concentric Spheres system was taught in the world, the earth was regarded as a vast and irregular plain, surrounded on all sides by the ocean.

Its roots extended infinitely deep
The sky was as a solid hemisphere, which covered the earth, and united with the ocean at the extremity of the horizon.
The Sun, the Moon, and all the heavenly bodies rose out of the eastern, climbed up the convex side of the heavens, and descended again into the western ocean.
The Earth was surrounded by the elements of Air and Ether, and covered by 8 polished and cristalline Spheres, each of which was distinguished by one or more beautiful and luminous bodies. These revolved around their common centre, by varied but equable proportionable motions.

This was believed by:

The Stoical System

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Cleanthes and the other Stoical philosophers had a system of their own.

They:

rejected the doctrine of the Solid Spheres
maintained that the celestial regions were filled with a fluid ether, of too yielding a nature to carry along with it, by any motion of its own, bodies so immensely great as the Sun, Moon, and Five Planets.

These, therefore, as well as the Fixed Stars, did not derive their motion from the circumambient body, but had each of them, in itself, and peculiar to itself, a vital principle of motion, which directed it to move with its own peculiar velocity, and its own peculiar direction.

The System of Copernicus

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The ruin of Roman Empire produced the entire neglect of the study of Nature.

The empire of the Caliphs established the peace required by the sciences.

It was under the protection of those generous and magnificent princes, that the ancient philosophy and astronomy of the Greeks were restored and established in the East.

Reception to Copernicus' System

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Copernicus completed his Treatise of Revolutions but was afraid of what people might think. And so he kept it in his closet for 30 years.

Tycho Brahe' System of Astronomy

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Tycho Brache was the great restorer and advancer of Astronomy.

He spent his life and wasted his fortune on it.
His observations were both more numerous and more accurate than those of all the astronomers who had gone before him.
- He himself was so much affected by objections to the point that he could not embrace the system of Copernicus

He admired Copernicus and all his astronomical observations tended to confirm his system. They demonstrated, that:

Kepler's System of Astronomy

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In Italy, the unfortunate Galileo added so many probabilities to the system of Copernicus.

In Germany, Kepler corrected and improved it.

Kepler had great genius but none of the taste or order and method of Galileo.

The Observations of Cassini

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The truth of both these analogies, intricate as they were, was at last fully established by the observations of Cassini.

Kepler first discovered:

that the moons of Jupiter and Saturn revolved round Jupiter and Saturn according to the same laws which Kepler had observed in the revolutions of planets around the Sun
that the revolution of the Moon around the earth had described equal areas in equal times
- the squares of their periodic times were as the cubes of their distances

These two last abstruse analogies were initially but little regarded. But when they were found to take place in the revolutions of the four moons of Jupiter, and in the five moons of the Five of Saturn, they confirmed Kepler’s doctrine and added a new probability to the Copernican hypothesis.

Descartes' System of Astronomy

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Descartes was the first who tried to ascertain precisely this invisible chain that Kepler said to link the planets to the sun.

He explained that the real inertness of matter was:

The Third Element: Matter

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The particles of the 1st Element can fill up the interstices of the 2nd ELement. Among this 1st Element, there are many which get an angular form from the pressure of the 2nd Element globules around them.

Isaac Netwon's System of Astronomy

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Keplers’ laws were cemented by the observations of Cassini. But there were still constant irregularities in the motions of heavenly bodies.

Sir Isaac Newton first attempted to give a physical account of the motions of the Planets to solve such irregularities.

Gravity and Mass

Mon, 01 Jan 0001 00:00:00 +0000

Newton and the Shape of the Planets as Oblate Spheroids

Before the theory of gravity, people thought that the Earth was perfectly globular.