SCIENCE 10 1ST LE

• Stephen Hawking


  A renowned physicist and cosmologist, made significant contributions to our understanding of the physical world
• The Grand Design


  explores the fundamental laws that govern the universe
• The Grand Design


  offers an overview of the latest scientific theories and discoveries, providing insights into the mysteries of the cosmos
• THE PTOLEMAIC UNIVERSE


  Viewed the earth as a motionless sphere positioned at the center of the universe
• THE PTOLEMAIC UNIVERSE


  The earth was negligibly small compared to the distance of the heavens
• THE PTOLEMAIC UNIVERSE

  Planets and stars moved around the earth
• THE COPERNICAN MODEL

  Sun was at the center of the universe and the planets revolved around it.
• THE COPERNICAN MODEL

  Held to “contradict” the Bible
• THE COPERNICAN MODEL


  During this time, the bible was written by people who believed that the earth was flat
• Which of the two models is correct?

  Depends on the point of reference.
• NATURE OF REALITY

  CLASSICAL SCIENCE and MODERN SCIENCE
• CLASSICAL SCIENCE

  All things that are visible to the naked eye is part of the physical world
• MODERN SCIENCE

  Uses models or representations to define things that are part of the physical world
• Model-dependent Realism


  It is pointless to ask whether a model is real, only whether it agrees with an observation. Corresponds to the way we perceive things. Solves or at least avoid the meaning of existence.
• QUARKS MODEL


  Explains the protons and neutrons inside the nucleus
• QUARKS MODEL


  Cannot be observed visually because of increasing binding force upon separation
• QUARKS MODEL

  Always exist in groups of three (protons and neutrons) or in pairs (quark and anti-quarks)
• QUARKS MODEL


  Agrees with our observations of how sub nuclear particles behave
• How do we study the physical world?

  Temporal Scale and Spatial Scale
• EDWIN HUBBLE (1889-1953)


  Proved the existence of other galaxies outside the Milky Way

  Took photos of Cepheid variable stars and compared the degrees of luminosity
• CEPHEID PERIOD-LUMINOSITY RELATIONSHIP


  A Cepheid’s pulses timing or period correlates with its inherent brightness. Longer pulse rate = More luminous star. Farther objects look dimmer.
• EDWIN HUBBLE (1889-1953)

  • Able to estimate the distance of the Andromeda galaxy from the Milky way.
  • Galaxies were made up of hundreds of billions of stars
  • Studied the movement of other galaxies by observing the wavelength light.
• RED SHIFT

  • The process of stretching wavelengths of light as the universe expands.
  • Longer wavelengths appear red
  • Shorter wavelengths appear blue
• RED SHIFT


  Distant galaxies have all of their visible light shifted into infrared.
• ARNO PENZIAS (1933)

  ROBERT WILSON (1936)


  Won a Nobel Prize in Physics on 1978 for their discovery of the Cosmic Microwave Background.
• HOLMDEL HORN ANTENNA

  • Located at Bell Telephone Laboratories, New Jersey
  • Built in 1959 for pioneering work in communication satellites for the NASA ECHO I
  • Used to discover cosmic microwave background
• HOW WAS THE CMB DISCOVERED?

  • Initially intended for detecting gas emissions in the Milky way
  • The antenna is pointed to an empty patch of sky
  • They observed a huge amount of noise which they thought was a problem in the system which later on was discovered to be the Cosmic Microwave Background