PHYSCI

• Around 500 B.C most Greeks believed that Earth was round, not flat
• BABYLONIAN'S (1500 BC)


  • POSITION OF PLANETS
  • CALENDAR
  • ECLIPES
  • ASTRONOMICAL RECORDS
• With early mankind recording and wondering of what lies beyond, there was DEVELOPMENT OF ASTRONOMY
• GEOCENTRISM


  Any theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the center of it
• ECLIPSE


  An obscuring of the light from one celestial body by the passage of another between it and the observer or between it and its source of illumination
• HELIOCENTRISM


  The astronomical model in which the Earth and planets revolve around the Sun
• OBLATE SPHEROID


  The shape of the Earth, with a bulging equator and squeezed poles
• SOLSTICE


  Either of the two times in the year, the summer solstice and the winter solstice, when the Sun reaches its highest or lowest point in the sky at noon, marked by the longest and shortest days
• Astronomy is a natural science that studies celestial objects and phenomena
• Pythagoras and his pupils were first to propose a spherical Earth
• Anaxagoras further supported Pythagoras' proposal through his observations of the shadows that the Earth cast on the Moon during a lunar eclipse
• Anaxagoras observed that during a lunar eclipse, the Earth's shadow was reflected on the Moon's surface, and the shadow reflected was circular
• Aristotle listed several arguments for a spherical Earth which included the positions of the North Star, the shape of the Moon and the Sun, and the disappearance of the ships when they sail over the horizon
• Aristotle argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was also spherical
• Aristotle observed that when the Greeks traveled to places nearer the equator, like Egypt, they noticed that the North Star is closer to the horizon
• Aristotle observed that if the Earth was flat, then a ship traveling away from an observer should become smaller and smaller until it disappeared, but the Greeks observed that the ship became smaller and then its hull disappeared first before the sail as if it was being enveloped by the water until it completely disappeared
• Hipparchus made a compilation of 850 stars and developed a method for predicting lunar eclipses
• Claudius Ptolemy proposed the geocentric model (Ptolemic system) that says the Sun, moon and other planets move in circular orbits around the Earth
• Aristarchus (310-230 BC) proposed the heliocentric theory, because he observed that the Sun is relatively larger than Earth
• Eratosthenes (276-194 BC) was a Greek mathematician who measured the circumference of Earth
• Annual Motion


  The apparent yearly movement of stars as observed from Earth as a direct effect of the Earth's revolution around the sun
• Precession of the Equinoxes

  The observable phenomena of the rotation of the heavens which spans a period of 25,920 years
• Hans Leppershey invented the refracting telescope in 1608
• Tycho Brahe


  • Danish astronomer and nobleman who made accurate observations of the movement of celestial bodies
  • Created quadrant
  • Created star chart
• Nicolaus Copernicus set forth the idea of a heliocentric solar system which the Vatican did not agree with
• Gnomon


  Instrument used by Babylonians and Egyptians in systematically observing the motion of the sun
• Phases of the Moon

  • New Moon
  • First Quarter
  • Full Moon
  • Last Quarter
• Pythagoras and his pupils were first to propose a spherical Earth
• Tycho Brahe's model of the universe

  • Earth is the center of the universe
  • Moon, sun, and stars revolve around the Earth
  • Other planets revolve around the sun
• Galileo Galilei


  • Observed phases of Venus
  • Observed moon craters
  • Observed moons of Jupiter
  • Observed sunspots that made him blind
• Johannes Kepler


  • German astronomer, mathematician and astrologer
  • Brahe's assistant
  • Formulated laws of planetary motion
• Brahe's data enabled Kepler to formulate his laws of planetary motion
• Brahe and Kepler had an unsteady working relationship
• Kepler's 1st Law (Law of Ellipses)

  Planets follow an oval or ellipse orbit
• Kepler's 2nd Law (Law of Equal Areas)


  The imaginary line drawn from the center of the Sun to the center of the planet sweeps out an equal area of space in equal time intervals
• Kepler's 3rd Law (Law of Harmonies)


  The square of a planet's orbital period is proportional to the cube of a planet's average distance from the sun
• The law of harmonics states that the squares of the orbital periods of planets are directly proportional to the cubes of semi major axis of their orbits
• Ellipses: Kepler's First Law


  Each planet moves in an Ellipse with its star as its focus. The farther, the longer the ellipse