PhySci

• Astronomy studies everything around the world.
• Cosmology studies the history (beginning) of the earth.
• Plato believes that Earth is perfect and eternal since every object moves towards the center of the Earth (unkwingly known as gravity).
• Aristotle believed that Earth was at rest, while other planets revolved around it.
• Ptolemy's geocentric model states that all celestial bodies move on circular orbits centered on the Earth.
• Copernicus proposed heliocentrism which means that the Sun is the center of our solar system.
• Exodus of Cnidus stated that there are 27 interconnected geocentric spheres revolving around Earth.
• Ptolemy stated that stars are fixed and are attached to the solid exterior of the Universe.
• Claudius Ptolemy stated that planets moves nearer or farther away from Earth even without stars.
• Johannes Kepler discovered three laws of planetary motion using Tycho Brahe’s observations.
• Plato believes that Earth has 4 elements.
• Aristarchus of Samus is the only Ancient philosopher who believes in the Heliocentric theory/model.
• Aristarchus of Samus estimated that the moon is 0.32-0.4x bigger than Earth and that sun is 6.3-7x bigger than Earth.
• Aristarchus of Samus estimated that Earth is 18-20 times farther away from Sun than in moon.
• Nicolaus Copernicus proposed the Heliocentric theory.
• Nicolaus Copernicus stated that the retrograde motion (distance) of planets is caused by the Earth‘S motion.
• Nicolaus Copernicus stated that stars are farther away to Earth than from Sun.
• Nicolaus Copernicus stated that Earth rotates around its own axis 24-7 and revolves around the Sun once a year.
• Nicolaus Copernicus stated that southern and northern countries experience four seasons while equatorial only experiences two seasons.
• Tycho Brahe is the only modern astronomer who still believes in Geocentric theory.
• Orlando Fergusun’s map of square ans stationary earth depicts a basin-like world where Earth is mount in middle and sides have icy edges.
• Erastothenes gave one of the accurate size of Earth without any scientific calculator or any mathematical or scientific instrument.
• Erastothenes measured Earth by;

  • Using angles produces by shadow from sun
  • Measuring cities through the number of stadiums present in it.
• Tycho Brahe‘s Tychonic system shows ;

  • fixed stars rotating on a sphere in the boundary of the universe.
  • All other planets revolves around the Sun and the Sun revolves around the Earth.
• Tycho Brahe discovered Supernova Cassiopeia in 1572.
• Tycho Brahe designed and build huge instruments to measure precise measurements of planet’s position.
• Tychonic system is Tycho Brahe’s modification of Geocentric model.
• Aristotle added three more spheres to Jupiter & Mars and four to Sun, Moon, Venus, & Mercury.
• Galileo Galilei used his telescope and discovered sunspots and rough surface of the moon.
• Galileo Galilei discovered the four famous Jupiter moons, called as Galilean moons, which are Io, Europa, Ganymede, and Callisto.
• Galileo Galilei discovered that Venus also have phases like the moon.
• Johannes Kepler- He discovered the three laws of planetary motion, the most accurate laws on how planets revolves around the sun.
• The first law of Kepler states that orbits/planets are ellipses (not a perfect circle) that focuses on the sun.
• Second law of Kepler states that the movement of planet is equal to the movement of Sun (Equal area at equal intervals).
• Third law of Kepler states that the motion of planets around sun is influenced by its radius and size.
• Perihelion is when a planet is nearest to the sun while Aphelion is when a planet is farther from the sun.
• The lesser the gravitational pull (faster movement), the farther the planet is from the sun. Whereas, the slower the gravitational pull (slower movement), the nearer the planet is to the sun.
• Natural motion requires no external/unnatural force.
• According to Aristotle, all objects are made up of four primordial elements that have tendency to move away to create a new structure.
• Aristotle’s first theory of natural motion states that objects made from Earth falls towards the center of the Earth.