Copernicus
In 1543, he published De Revolutionibus Orbium Coelestium, marking the start of the
Scientific Revolution.
He agreed with Aristotle + Ptolemy that heavenly bodies moved in perfect circles but
suggested that the universe was made of 8 spheres, with the Sun at the centre and the
planets revolving around it, with each in its own sphere and didn’t interfere with each other.
• The Earth revolved on its own axis and the Moon around the Earth in its own sphere.
Copernicus had to present his idea as platonic theory rather than Aristotelian fact to avoid
being accused of blasphemy, as this went against religious beliefs.
• This suggests that the climate he was working in was hostile towards what he was
trying to propose.
His idea therefore challenged both Aristotle and Ptolemy, and religious belief. This is shown
in the fact that his book was banned in 1616 by the Catholic Church.
THE SIGNIFICANCE
Copernicus’ work is significant as it became highly influential and his findings were
accepted in many intellectual circles, although not in his lifetime.
• However, his work had a gradual impact.
• His ideas weren't taken seriously as everyone was still fixated on religious doctrine.
THE LIMITS OF HIS FINDINGS
Some view Copernicus as a conservative rather than a revolutionary.
• He made theoretical conclusions rather than empirical observations.
• He still believed the planets and stars moved on spheres, but wasn’t sure what these
speres were made of
• He still believed all planetary movements were perfectly circular.
Most people thought the idea of the Earth moving was so counterintuitive that it was
impossible. -- it also contradicted biblical accounts.
Recent study shows that only 10 thinkers accepted his theory as physical truth pre-1600.
Kepler
Kepler took a more Aristotelian approach rather than Copernicus with his theoretical
approach.
He adopted heliocentric view of Copernicus but avoided his reliance on spheres +
epicycles.
THE INFLUENCE OF BRAHE
in 1600, Kepler met Brahe and began working for him.
, He believed that all planets circled the Sun, but that the Sun circled the Earth.
• This was inaccurate but important in developing understanding of orbits.
He observed a new supernova in his findings – this posed a problem to astronomers who
followed the Aristotelian/ Ptolemaic view of the universe as it went against the opinion that
the Earth was stationary.
He also observed several comets + concluded that they existed outside the atmosphere of
the Earth.
• Brahe realised this must mean that the idea that all heavenly bodies moved in
perfect spheres was redundant.
He was also able to refute the notion that Medieval astronomers referred to solid entities
when talking about spheres on which the planets travelled, and instead argued that planets
moved independently in space > a new explanation was needed.
KEPLER’S IDEAS
Kepler proposed a system whereby 6 layers of 3-dimensional shapes nestled together
would correspond to the path of the 6 planets.
- Although he later rejected this model, it initiated discussion/ interest.
Kepler's first 2 laws of planetary motion (published 1609 in Astronomia Nova):
- The planets travel in elliptical orbits around the Sun.
- Planets don’t travel at a consistent speed – the speed varies as they circle the Sun,
the closer the faster and vice versa.
Kepler provided a physical explanation based on his own observations > he was therefore
using the approach of both a natural philosopher and mathematician.
He published his third law in Harmonices Mundi which states the distance from a planet to
the sun, cubed, is proportional to the time it takes for a planet to complete its orbit.
- He therefore concluded that the further a planet is from the sun, the longer it takes to
complete an orbit > however, he didn’t understand gravity and the suns gravitational
pull + therefore this theory didn’t take hold until Newton.
He was unaware of the impact his third law would have on Newton + was more
preoccupied with ‘discovering Gods plan’. It was only until Newton that people realised the
significance of his law.
KEPLER AND RELIGION
We know Kepler was religious as religious devotion can be seen in his work as an
astronomer.
• He saw astronomy as religious duty as it would help him further understand the
world God had created.
In 1543, he published De Revolutionibus Orbium Coelestium, marking the start of the
Scientific Revolution.
He agreed with Aristotle + Ptolemy that heavenly bodies moved in perfect circles but
suggested that the universe was made of 8 spheres, with the Sun at the centre and the
planets revolving around it, with each in its own sphere and didn’t interfere with each other.
• The Earth revolved on its own axis and the Moon around the Earth in its own sphere.
Copernicus had to present his idea as platonic theory rather than Aristotelian fact to avoid
being accused of blasphemy, as this went against religious beliefs.
• This suggests that the climate he was working in was hostile towards what he was
trying to propose.
His idea therefore challenged both Aristotle and Ptolemy, and religious belief. This is shown
in the fact that his book was banned in 1616 by the Catholic Church.
THE SIGNIFICANCE
Copernicus’ work is significant as it became highly influential and his findings were
accepted in many intellectual circles, although not in his lifetime.
• However, his work had a gradual impact.
• His ideas weren't taken seriously as everyone was still fixated on religious doctrine.
THE LIMITS OF HIS FINDINGS
Some view Copernicus as a conservative rather than a revolutionary.
• He made theoretical conclusions rather than empirical observations.
• He still believed the planets and stars moved on spheres, but wasn’t sure what these
speres were made of
• He still believed all planetary movements were perfectly circular.
Most people thought the idea of the Earth moving was so counterintuitive that it was
impossible. -- it also contradicted biblical accounts.
Recent study shows that only 10 thinkers accepted his theory as physical truth pre-1600.
Kepler
Kepler took a more Aristotelian approach rather than Copernicus with his theoretical
approach.
He adopted heliocentric view of Copernicus but avoided his reliance on spheres +
epicycles.
THE INFLUENCE OF BRAHE
in 1600, Kepler met Brahe and began working for him.
, He believed that all planets circled the Sun, but that the Sun circled the Earth.
• This was inaccurate but important in developing understanding of orbits.
He observed a new supernova in his findings – this posed a problem to astronomers who
followed the Aristotelian/ Ptolemaic view of the universe as it went against the opinion that
the Earth was stationary.
He also observed several comets + concluded that they existed outside the atmosphere of
the Earth.
• Brahe realised this must mean that the idea that all heavenly bodies moved in
perfect spheres was redundant.
He was also able to refute the notion that Medieval astronomers referred to solid entities
when talking about spheres on which the planets travelled, and instead argued that planets
moved independently in space > a new explanation was needed.
KEPLER’S IDEAS
Kepler proposed a system whereby 6 layers of 3-dimensional shapes nestled together
would correspond to the path of the 6 planets.
- Although he later rejected this model, it initiated discussion/ interest.
Kepler's first 2 laws of planetary motion (published 1609 in Astronomia Nova):
- The planets travel in elliptical orbits around the Sun.
- Planets don’t travel at a consistent speed – the speed varies as they circle the Sun,
the closer the faster and vice versa.
Kepler provided a physical explanation based on his own observations > he was therefore
using the approach of both a natural philosopher and mathematician.
He published his third law in Harmonices Mundi which states the distance from a planet to
the sun, cubed, is proportional to the time it takes for a planet to complete its orbit.
- He therefore concluded that the further a planet is from the sun, the longer it takes to
complete an orbit > however, he didn’t understand gravity and the suns gravitational
pull + therefore this theory didn’t take hold until Newton.
He was unaware of the impact his third law would have on Newton + was more
preoccupied with ‘discovering Gods plan’. It was only until Newton that people realised the
significance of his law.
KEPLER AND RELIGION
We know Kepler was religious as religious devotion can be seen in his work as an
astronomer.
• He saw astronomy as religious duty as it would help him further understand the
world God had created.
