Galileo and the Church Science and Religion History 1616 The Church condemned a sun centered solar system believing that the Earth was the center o They ordered Galileo to abandon his views of a sun centered solar system o He refused so he was tried and convicted of proclaiming a doctrine contrary to religious doctrine Put under house arrest for the last 10 years of his life 1992 The Church forgave Galileo Galilei Motion of the Planets According to Greek studies 600 BC 150 BC Geocentric earth was in the center of the universe o The earth was believed to be spherical motionless and surrounded by the celestial sphere a transparent hollow sphere Stars hung on the celestial sphere and were carried on a daily trip around the Earth ex the stars rise and set like the Sun and Moon Except for SEVEN objects Sun Moon Mercury Venus wanderers and 5 Claudius Ptolemy Mars Jupiter and Saturn Wanderer Greek word for planet o Ptolemaic System the geocentric model of the universe 141 BC Problem Retrograde Motion of the planets o Planets moved eastward against the background of the stars but occasionally they appeared to stop reverse direction for several weeks then resume in eastward motion Solution Epicycle each planet s small circular path Deferent the larger circular path that a planet takes while it orbits around another object Obstacle During the Renaissance his calculations were no longer relevant Nicholas Copernicus 1473 1543 o Heliocentric the sun is the center of the universe First suggested by Aristarchus in the 3rd century BC as a solution to the planets retrograde motion Problem WHY CAN T THE SUN BE IN THE CENTER The Earth would have to be moving BUT o The Earth doesn t feel like it s moving o Parallax a phenomenon in which the stars would seem to have different relative positions when the Earth was in motion rather than everything having the same position while the Earth was motionless o The Bible humans should be the central purpose of creation so why aren t we the center of the universe o Facts of Copernicus Time 1 The Earth is planet just like the other five wanderers 2 The daily motion of heavenly objects could be explained by the rotation of the Earth 3 The Sun is at the center of the Solar System a Planets orbit the Sun in circles Johannes Kepler 1571 1630 o Attempted to make a more accurate model of the position of the planets to compensate for Copernicus observable mistakes Result rather than a circular path the planets take an elliptical path Ellipse a geometric curve with the sum of the differences from two fixed points foci is a constant The lower the eccentricity the closer the ellipse is to a circle Galileo Galilei 1564 1642 o Supported the Copernican theory of a heliocentric solar system o Studied the behavior of moving objects The rate at which objects fall to the ground Legend he dropped two objects from the Leaning Tower of Pisa 1 heavier than the other o 1st hypothesis heavier object would fall faster o 2nd hypothesis both objects would fall as the same speed o Result in the absence of air resistance OR gravity all objects fall to the ground at the same speed o Constructed his own the first telescope o Studied moons orbiting Jupiter Discovered 4 moons orbiting around Jupiter o Observed planets as circular disks RATHER THAN points of lights Supported the idea that other planets could be Earth like o of Studied phases Venus He realized that Venus had phases similar to the phases of our Moon suggesting that both Venus and the Moon orbit the sun Kepler s Laws the WHY o Empirical derived strictly from observation without a theoretical foundation VS Theoretical Foundations explanations of how things work based on an understanding of the phenomenon being explained the HOW o Downfall predict planetary motions accurately but they DO NOT explain they move the way they do WHY Isaac Newton planets move the way they do o 3 Laws of Motion o Further developed Galileo s ideas to create theoretical explanations of WHY the 1 A body at rest remains at rest and a body in motion continues to move in a straight line with a constant speed unless acted upon by a force 2 The acceleration of an object is directly proportional to the net force exerted and inversely proportional to the object s mass 3 For every action there is an equal and opposite reaction o Gravity All falling objects accelerate at the same rate neglecting air resistance o On Earth 9 8 m s 2 for every 1 second falling 1 sec 10 m s 2 2 sec 20 m s 2 3 sec 30 m s 2 For every 8 000 meters the Earth curves downward by 5m o In an objects 1st second of falling it falls 5m