PHY SCI - 4Q

• Map of the square and stationary earth

  • Orlando Ferguson published the map showing it in a stationary and square way and not spherical
  • It is like a basin and in the middle part of it, there is a hump [umbok]. In its edges are where the boundary of the earth, and it is also where icy edges of the earth are located
  • He states that the outermost part of the earth is square
  • In his depiction of geography, he it would be easy for him to convince the people in his time that the earth is square, however, because he claims that the earth is square, it is hard to believe in his map
  • This has been disapproved already

  
• Pythagoras


  • Made the Pythagorean Theorem [in Mathematics]
  • He was the first one to originate a spherical earth using observations such as: North and South Constellations; Sinking Ships; and Lunar Eclipse
  • In the field of astronomy, he taught that the world is spherical and he was able to theorize that the things that exist other than the world are also sphere in shape, so his term for heavenly bodies are "spheres" [this includes the sun, moon, and stars]
  • Constellations are moving, in a way that the planet is moving in a circular motion. As you travel constellations look like they are revolving around
  • Sinking ships - he noticed that when a ship is sailing away, the ship is going down, when in fact, the sea is not eating the ship. If the path is straight and flat, the ship will only be small as it will go farther away from his sight, but if the earth is sphere, the ship will look like it's going down
  • Partial lunar eclipse is when the Sun, Earth, and Moon align, but only a part of the Moon enters the Earth's shadow. He noticed that when a partial lunar eclipse happens, there is a curvature in the shadow of the earth that is reflected in the moon. He claims that if the earth is not spherical, the curvature wouldn't appear as a "curvature" on the moon

  
• Plato


  • The earth is a form of a globe having its extremes in every direction equidistant from the center
  • At the center of the universe
  • Perfect and eternal
  • Has four elements
  • He also taught that the earth was spherical. But, he did not have that much justification in his findings
• Aristotle

  • His work on 350 BC entitled, "On the Heavens" initiated the idea of a geocentric universe with fixed spherical earth as its center
  • He also believes that: The Earth is spherical and earth has 4 elements
  • Rounded shadow - shadow ng earth has curvature has it has reflection in the moon
  • Change in constellations
  • Indirect idea on gravity
• Erastosthenes


  • Ancient scholars tried to provide proof of a spherical Earth and its circumferences through calculations. It was Eratosthenes who gave the most accurate size (through non-scientific calculations) during their time
  • From the shadow projected by the sun, they have angular measurement. Aside from the shadow projected by the sun, he also measured the size of the earth,by measuring the stadium in the size of a city. [kung ilang stadium ang kasya sa isang city]
• Geocentric Theory


  A theory that states that the earth is in the middle of the Universe. The Sun, other planets, and other heavenly bodies are orbiting around the earth.
• Heliocentric Theory


  Theory that states that the Sun [Helio or Helios] is the center of the Universe. The plants including the earth, and other heavenly bodies are the one that surrounds it.
• Geocentric Theorists

  • Plato
  • Ptolemy
  • Aristotle
  • Tycho Brahe (Modern)
• Heliocentric Theorists


  • Aristarchus of Samos (Ancient)
  • Galileo Galilei
  • Nicolaus Copernicus
  • Johannes Kepler
• Astronomy


  Study of the earth, atmosphere and the things that we can see with our naked eyes
• Cosmology


  • Timeline of when the Universe started
  • Focuses of the structure of the universe including the presence of the things above the sky [Sun, Moon, Stars]
  • More focused on the history
• Plato (Ancient Astronomy)


  • He believed that the universe is perfect or ethereal and unchanging
  • He further described the stars embedded in the outer space as eternal and divine
  • What uniform and ordered circular motion must be assumed for each of the planets to account for their apparently irregular annual paths?
  • He believes that the earth is unchanging, perfect, divine, ethereal, and not evolving
  • All of the objects [spheres] are actually fixed and they are just rotating and revolving around the earth
  • Believe in geocentric
• Exodus of Cnidus (Ancient Astronomy)


  • According to him there are 27 interconnected geocentric spheres [spheres that revolve around the earth]
• Aristotle (Ancient Astronomy)


  • In conjunction to Exodus' model, he added 3 sphere to Jupiter and mars; 4 spheres to Sun, moon, Venus, and Mercury
• Claudius Ptolemy (Ancient Astronomy)


  • Earth is spherical object
  • The stars are fixed bodies attached to a solid spherical exterior part of the universe
  • Planets moved independently of the fixed stars and that sometimes, the planet seem to reverse their motion [lumalapit, lumalayo, lumalapit, lumalayo]
• Aristarchus of Samos (Ancient Astronomy)


  • He stated that sun and stars are fixed
  • Estimated the sizes of the Sun and Moon as compared to Earth's size (Moon's diameter was 0.32-0.40x the diameter of the Earth and the Sun's diameter was 6.3-7.2x the diameter of Earth)
  • Estimated the distances from the Earth to the Sun and Moon (Sun is about 18-20x farther away from Earth than Moon)
  • More focused on the size of the Stars and Sun more than the size of the Earth
  • Stated that the distance of the Earth to the Sun is farther away than the Earth to the Moon
• Modern Astronomy


  • The observations became more quantitative in nature
  • The theories formulated are based on logic and mathematical concepts
• Nicolaus Copernicus


  • He corrected the Geocentric Theory and proposed the Heliocentric Theory with the following postulates:
  • Earth is considered as only one of the planets
  • Earth rotated on its axis daily and revolves around the sun once a year
  • Annual tilting of its axis - causes change in season
  • The retrograde motion of the planets is explained by Earth's motion - the motion of the earth dictates our perspectives about such heavenly bodies
  • The distance from Earth to Sun is small compared to Earth's distance from the stars - The nearest star to us is the Sun, the rest of the stars that we see in the sky are far away from us na
  • Tilting of the Earth and the Four Seasons
• Tycho Brahe


  • He modified the geocentric model of the universe
  • He designed and built huge instruments used to make precise measurements of the positions of the planets
  • He discovered supernova in the constellation Casseiopeia in 1572
  • He made observations of planetary motions that are important to the development of Kepler's Laws and other models of Solar System
  • Tychonic System - System has boundaries of stars rotating in spheres, The other planets and stars revolve around the Sun and the Sun orbits the Earth [so we can say that it revolves around the Earth, which is geocentric]
• Galileo Galilei


  • He discovered sunspots and rough surface of the moon
  • He discovered the 4 famous moons of Jupiter known as Galilean moons (lo, Europa, Ganymede, Calisto)
  • He discovered that Venus has phases like the moon
• Johanne Kepler


  • 3 laws regarding planetary motion
  • Most accurate laws that defines how planets would rotate around the sun or their axis
  • First Law: It states that the orbits of the planets are ellipses, with the Sun at one focus
  • Second Law: It states that an imaginary line drawn from the sun to a planet sweeps out equal areas in equal intervals
  • Third Law: The cube of the radius of the orbit of a planet around the Sun is proportional to the square of its period of revolution
• Most modern astronomers [except Brahe] - They believe in Heliocentric Theory because technology is more advanced and their theories are based on math and logical concepts.
• What Makes the theories about heavenly bodies in modern astronomy more accurate than the theories developed in ancient astronomy?
• How is the Copernican theory related to the Ptolemaic theory?
• What is Tycho Brahe's important contribution to modern astronomy?
• Most ancient astronomers only used their naked eyes to observe and make theories about the Earth, which makes it hard to be accurate since there isn't enough evidence that can help strengthen their theories
• Modern astronomers have advanced technology that helps them to develop and find evidence on their observations and findings. Furthermore, their theories are based on mathematics and logical concepts
• Tycho Brahe's important contributions to modern astronomy

  • He modified the geocentric model of the universe
  • He designed and built huge instruments used to make precise measurements of the positions of the planets
  • He discovered supernova in the constellation Casseiopeia in 1572
  • He made observations of planetary motions that are important to the development of Kepler's Laws and other models of Solar System
  • Tychonic System

  
• Brahe's observations and theories

  Influenced the development of Heliocentric Theory
• Proofs that debunked the flat earth idea

  • Sinking ships
  • Partial lunar eclipse by pythagoras

  
• Aristotle's theory of motion


  • All objects on Earth were believed to be a mixture of four primordial elements
  • Motion is of two types: Natural and Violent
• Aristotle had vague observations because he did not have instruments thus did not have accurate findings
• Primordial elements


  • All structures of the earth is made up of primordial elements
  • The 4 primordial elements can combine to form new structures. The new structures are made up of any 2 primordial elements
• Natural motion


  • It exists as any type of motion that a body does naturally without forcing the motion to happen
  • No force is applied
  • Force of the nature that is taking place
  • All objects have the tendency to move in their natural place in the form of natural motion
• Four theories of natural motion

  • An object which is made up of an "Earth" material, falls toward the center of Earth because it seeks its natural place
  • Heavy object fall faster than light ones
  • Objects fall faster in air than in water
  • Objects sometimes move away from their natural places
• Violent motion


  It exists when a motion requires a force to make an object move in an "unnatural" manner
• Aristotle's equation of motion has been debunked
• Longevity of Aristotle's theory of motion


  • The theory was consistent with common sense
  • No other scientist formed theories regarding motion
  • The quantitative method of observation to prove the validity is not yet developed
• Galileo's findings about motion

  • The two objects (light and heavy), dropped simultaneously from the tower of Pisa, fell and struck the earth at the same time (Acceleration Due to Gravity)
  • A marble made to roll on a flat surface would roll for an infinite amount of time (Paved the way for the Law of Inertia)
  • When a marble was rolled down on an inclined plane at a fixed angle, the ratio of the distance (d) covered and the square of the corresponding time (t) was constant (velocity)
  • The gravitational force of the earth on a freely falling object causes the object to be uniformly accelerated as it goes toward the surface of the earth. The distance covered to the square of the corresponding time was always the same (Uniformly Accelerated Motion)
• Kinematics equations/formulas


  • d = 1/2 at^2
  • v^2 = v_i^2 + 2ad
  • v = v_i + at
  • d = v_i t + 1/2 at^2
  • v_f^2 = v_i^2 + 2ad