The retrograde motion of a planet is the optical illusionthat a planet reverses its orbital direction, as seen from Earth.
In reality, the planet does not change direction at all, but because the Earth is also orbiting the sun, the relative motion of the Earth and another planet in their respective orbits make it appear to us as if the planet reverses course for a while.
Claudius Ptolemy lived in the second century, A.D., at which time Rome was arguably the strongest empire in the world. In South Asia, many Hindu and Buddhist texts were committed to writing in the second century A.D.
The astronomical system of Ptolemy, in which the earth is at the center of the universe with the sun, moon, planets, and stars revolving about it in circular orbits.
Ptolemaic system Ptolemy believed that Earth was at the center of the universe and that the Sun and planets orbited Earth (with the planets also moving in smaller circles called epicycles). In this system, the centers of Mercury's and Venus's epicycles always lie on the line shown in the diagram between the Earth and the Sun.
Claudius Ptolemy was a Greco-Egyptian writer, philosopher, mathematician and astrologer. He lived in Alexandria Egypt and that is where most of his notable work was done.
Galileo and Copernicus were two of the scientists to disprove Ptolemy's geocentric theory of the universe. The Ptolemaic theory stated that the center was earth.
Im thinkin that it was made when he decided to look up at the sky one night and decided he would make an astronomical observation. idk just that's how i would make an oservation of the sky.
[Rosco P. Coltrain]
he thought it went around in a line and back to the earth...
Copernicus was correct in believing in the heliocentric model of the Solar System, which said the planets rotated round the sun. Ptolemy accepted the traditional geocentric view which had the Earth at the centre of the Solar System.
Never. It was one of the theories that were in play during his lifetime, and eventually the heliocentric theory, with the planets orbiting the Sun, was generally accepted. But it was Kepler's theory that has been accepted rather than Coprnicus's theory as supported by Galileo.
Whether the Sun was at the centre or not was only part of the whole theory, and Kepler's elliptical orbits are now believed to represent the correct model, and not Copernicus's model which used circles and epicycles.
This is a cylindrical map projection. It is a standard map for nautical purposes because it represents lines of constant course, called Rhum Lines, as straight segments. This is precisely the type of route employed by ships at sea. Compasses are used to indicate geographical direction and to steer the ship. The projection was presented by Mercator in 1569
It fails to describe the basic motions of the planets without a number of "arbitrary" actors. It fails to describe the now-observed motions of the host of stars around us.
Ptolemy's theory accounted mathematically for the movement of the planets, Sun and Moonand the stars.
However, Ptolemy thought the Earth is the center of the universe, which is wrong. Galileo helped prove that the Sun is the center of our solar system by the use of his homemade telescope. Ptolemy thought that the Sun, planets, and stars rested on crystal spheres that revolved around Earth. Ptolemy had toput in things called "epicycles" and other ideas, to make his system work.
There are various possibilities. The source of the ancient name was the same as the source of the English word "polemic." In ancient times it may have been pronounced with the T, the P, or both. An alternate spelling in ancient Greek was "Polemos," which is how it appears in Homer, and a nephew of Antigonus I (382-301 BC), was named Polemaeus. It comes into modern Italian as "Tolomeo," and ancient Aramaic as "Talmai," but the modern Arabic equivalent is transliterated as "Batlemos," pronouncing both the P (converted to a B) and the T.
Some said he drowned in the river of NILES, and some say he died of a certain disease. Nobody is sure because history can end up in lots of possibilities.
Because plain circular orbits could not explain the way the planets move. The philosophers said that the circle was the perfect curve, and Ptolemy's model used circles and epicycles.
An epicycle is a small circle whose centre travels round a larger circle, and the planet then travels round the epicycle. Extra epicycles were added to account for things like the eccentric orbits (which are now recognised as elliptical), and the inclination of the orbits.
However Ptolemy's model represented the movements of the planets pretty accurately which is why no-one thought to challenge it for 1400 years. Ptolemy's model was also in use in planetariums until modern times, when computer driven planetariums took over.
In Ptolemy's model both Venus and Mars have very large epicycles, which we now understand are there to account for the Earth's movement round the Sun.
Both Copernicus heliocentric and the Ptolemaic models agreed on the need for epicycles. These were miniature orbits that the celestial bodies travelled on as well as their normal orbits.
Copernicus still invigaed the bodies orbiting in perfect circles and had to put these in to explain some of the movements of the planets. This may have contributed to his ideas being largely dismissed as it was just as complicated as the already established model. It was not until Kepler proposed elliptical orbits was this problem resolved.
Claudius Ptolemy developed the mathematical astronomy used in Christian and Muslim countries up until the 16Thcentury.
Christopher Columbus and Magellan used Ptolemy's version of the world map during their voyage, but they did not know it was incorrect, thus not ending up where they planned to be.
He found the position of over one thousand stars.
Both models explain it simply, and even a simple model with circular orbits explains it easily. Normally, as the planets rotate round the Sun, they appear to move along the ecliptic from west to east. But in the short period around opposition, when the planets are opposite the Sun in our sky, and we are closest to them, they appear to move east to west because they are going round more slowly than us - we are overtaking them. That is retrograde motion.
The astronomer Ptolemy was almost certainly not married to his own sister. The Egyptians, and the Greeks, were not permitted to marry their sisters unless they were royal. The Ptolemaic kings were not pharaohs, but they did adopt the pharaohs' practice of marrying their sisters to keep the royal bloodline pure. It was probably not a very good idea.
The people who gave birth to him.
If you want more info go and ask him.