Johannes Kepler replaced circles with ellipses in the heliocentric model of the universe.

• When he saw that there were planets AND stars orbiting around earth.

Aristarchus was a Greek astronomer who theorized that the Earth rotated on its axis and revolves around the sun. None of his work has ever been discovered, but his ideas live on today and are the basis for many astronomical theories.

Ptolemy considered the solar system (and the universe) to be a set of crystal concentric spheres rotating around the stationary Earth at its centre.

On the closest sphere was the moon, then Venus and so on out to the stars on the outer sphere. At the time they didn't have any idea how incredibly big everything is.

Was he born in Rome? No, he was probably born in Egypt. However, at that time Egypt was part of the Roman Empire (as was everything from Egypt to Greece to Italy to Germany to England). He died in Alexandria, the city in Egypt at the mouth of the Nile

Was Ptolemy a Roman citizen? Almost certainly.

Claudius Ptolemy, an Egyptian geographer, mathematician, and astronomer, is credited with the Ptolemaic Model of the solar system. His model posited not only that the Earth was the center of the entire universe and assumed that the planets all moved in epicycles--small circles--that also moved along even larger circles called deferents.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

Please be more specific in regard to Ptolemy -- there were many. One was a mathematician/astronomer and the other was a general of Alexander the Great who founded the last pharonic dynasty in Egypt. There were 15 Ptolemies who followed him and many of them had a relationship with Rome.

The Ptolemaic system dates back to about 140 AD and has the Earth at the centre of the universe and everything else around it. This view was incorporated into the scriptures. It explains the planets' movements among the stars quite accurately and was used into modern times in the mechanisms of planetariums until computerised mechanisms came along.

It was not until 1543 that Copernicus published an alternative view, in which the Sun is at the centre and the planets' orbits are geometrically simpler. Kepler produced another Sun-centred model in 1609 with the planets in elliptical orbits. This latest theory was eventually accepted by astronomers after it was married up with the new theory of gravity and the laws of motion.

Some of the books he wrote include:

1. The Almagest (13 books long; It was originally titled the Syntaxis Mathmatica, which was called the Megale Syntaxis. When it was translated into Arabic it was called the al-Magisti, and when it was translated into Latin it was called the Almagestum. Finally it was translated into english-- The Almagest).

2. Tetrabiblos (Astrology/geography)

3. The Geographica (maps, atlas-- 7 books long)

4. A book on Optics which was reportedly 5 books long.

If you mean Claudius Ptolemaeus, no. He lived about 1900 years ago.

The Earth was, he believed.

Copernicus produced his model with the Sun at the centre in 1543, and then in 1609 Kepler produced the model that we use now. Kepler's model also uses the idea of having the Sun at the centre. No-one proved anything but after Newton's discoveries in physics it was realised that Kepler's model fitted exactly with Newton's later theories in gravity and dynamics, so that's why it became accepted, and it still is.

Gerhard Kremer, also known as Geradus Mercator (it was fashionable to have a Latin nickname in the 16'th Century), produced his first map in 1537.

Ptolomy, who liked to call himself Claudius Ptolemaeus, did his thing in the 2'nd century - so, somewhere between 100 and 200 A.D.

Soooo... Ptolomy wins!! by 14 centuries !!!!

The current model of the solar system is the "heliocentric system" meaning sun is the center of the solar system.

Hope this helps :)

earth

Yes.

We now understand that all the planets travel round the Sun, and a planet's retrograde motion happens as the Earth overtakes the other planet in its orbit. The Earth goes round more quickly than all the outer planets from Mars onwards.

In Ptolemy's model the Earth is stationary in the centre, and the planets move on circles and epicycles.

Using Mars as an example and assuming the orbits of Earth and Mars are circular for simplicity, the Earth is at the centre and then Ptolemy's model has a circle (or deferent) round it with a radius of 1.524 units. The epicycle is a smaller circle whose centre travels round the deferent in 687 days. The epicycle has a radius of 1.000 units and Mars travels round this in 365 days.

That was Ptolemy's geometric construction to explain the motion of Mars, which it does pretty accurately, and the retrograde motion happens when Mars on its epicycle moves close to the Earth.

Ptolemy used additional epicycles to allow for what we now call eccentricity in Mars's orbit, and also for what we now understand is the orbit's inclination to the ecliptic.

Empyrean

Ptolemy was an early Greek astronomer, and as most people believed, Ptolemy thought the solar system was geocentric. This meant that Earth was at the center, it was the most important thing, and that all celestial bodies circled it.

Ptolemy was born on 85 A.D

Copernicus proved that earth is the center of the universe

The very center. he belived everything revolved around the earth.

hope this is what you want :)

Ptolemy's model of the universe incorporated the concept of epicycles, where planets moved in small circles on larger orbits around the Earth, to explain the observed retrograde motion of planets. This was a significant departure from the earlier Greek model, which had planets moving in perfect circles along a single path.

Ancient astronmers used shell theory. The earth was center, then came the moon, planets and sun, then other stars. At first it was a circular system. It seemed more "perfect", that degenerated into ellipses as the mathematics didn't work out.

When Galileo observed that there are satellites which orbit the planet Jupiter, this was clear evidence that not everything orbits the Earth.