What are the contributions that Galileo Newton and Brahe made to astronomy?

Answer 1

Galileo used more advanced technology to find stronger observational evidence than Copernicus was ever able to provide.

Answer 2

Both scientists challenged ideas supported by the Roman Catholic Church.

Answer 3

Copernicus: a new heliocentric theory that he said was simpler than the old Ptolemaic theory but was actually a little more complicated (more epicycles).

Brahe: many observations and measurements of planets' positions with higher accuracy than ever before.

Kepler: used Brahe's observations to deduce the 3 laws of planetary motion (orbits).

Galileo: discovered moons orbiting Jupiter (and not the Earth like everything else was supposed to do by most people at that time).

Newton: Laws of motion, inverse-square law of gravity, differential calculus, explained why the planets obey Kepler's 3 laws.

Answer 4

It all happened in 150 years of intrigue and skullduggery from 1540 to 1690.

Copernicus put forward a new theory of the planets that put the Sun at the centre, with the Earth orbiting round it just like all the other five known planets. This challenged the old Ptolemaic system and it also challenged the church's teaching, which worried Copernicus and his book 'De Revolutionibus' was not published until the year he died, 1543.

Galielo took up the Copernican theory after observing the moons of Jupiter and the phases of Venus with his telescope, which he believed showed a fault in the Ptolemaic system. He started a dispute about the Copernican system with the catholic church authorities, and was eventually forced to recant for lack of enough proper evidence supporting it at that time.

Kepler took part of the Copernican system, the part that puts the Sun at the centre, and produced a new model based on observations made by Tycho Brahe with unprecedented accuracy. The planets were now in elliptical orbits following Kepler's three laws, published in 1609. These were based entirely on observations and he had no idea why the planets followed his laws.

In 1687 Newton had done a lot of theoretical work and published his famous 'Principia' in which he described the laws of motion and the newly discovered differential calculus, as well as the inverse-square law of gravity. He was able to use these to show by detailed mathematics that an object in orbit round a massive object, under the force of gravity, must follow an elliptical orbit, with the massive object at one focus, just as Kepler had found for the planets.

That is why Newton was voted the top physicist of all time by a panel of 100 top scientists, followed by Albert Einstein and James Clerk Maxwell.

Answer 5

Galileo promoted Copernicus's model of the planets, with the Sun at the centre, on the grounds that it explained the phases of Venus, which the earlier Ptolemiac system with the Earth at the centre failed to do.

However Tycho Brahe produced an alternative system that had the Earth at the centre while correctly explaining the phases of Venus. It allowed Venus to have the gibbous phase which Galileo had discovered and which is not predicted by the ancient model of Ptolemy.

Tycho's major contribution to science was to make a new set of accurate observations of the positions of the planets, which Kepler then used to produce a new model of the solar system which had all the planets in elliptical orbits, with the Sun at the centre.

So there were four systems in contention, until Newton worked out how to explain the planets' orbits using the new theories of gravity and motion. The new discoveries showed that Kepler's model was the one that agreed with the theory, and it is the model that is used today, with tiny corrections from Einstein's General Theory of Relativity.

Answer 6

Both scientrusts challenged ideas supported by roman Catholic church