Issues Regarding the Development Of A Cosmology Curriculum

1
Issues Regarding the Development Of A Cosmology
Curriculum

• 1) There seems to be very little research
  regarding teaching cosmology to students at the
  high school level
• 2) It is a field in which model revision is
  highly dependent on data gathered via technology,
  some yet developed
• 3) It is a science, as with evolution, in which
  the models are constructed utilizing many
  inferences regarding historical events
• 4) Evidence" for models often results from
  mathematical deductions or computer simulations
• 5) It is a science in which the models of
  explanation have often been in conflict with
  others that were/are seemingly as valid

2
Overarching Questions Of Cosmology
3
Other Questions ToBe Addressed
4
An Exploration Of Two ModelsOf The Universe (An
Attempt To Highlight/Address The Previous
Questions)

• Steady State Model
• Popular until the 1950s
• Main problems
• Necessitates creating new material from nothing
• Requires special process to create microwave
  background radiation
• Predicts that overall appearance of universe
  should not change over time

• Big Bang Model
• Growing evidence for
• 1964 serendipitous discovery by Penzias and
  Wilson regarding background, uniform cosmic
  radiation seems best proof
• Based on Doppler Effect and photons being
  stretched to microwave radiation

5
Both Models Allow For Expansion Of Universe

• In addition, a study of the development of this
  idea sets the stage for the rest of unit,
  historically and in terms of student familiarity
  with skills and knowledge
• Evidence is galaxies movement away from one
  another
• Is historical controversy over existence of
  galaxies, so ripe for historical reconstruction
  of a model
• Evidence for the movement of galaxies offered in
  the early 1900s, though implications not
  recognized by scientific community until decades
  later
• Galaxy movement/expansion of the universe
  measurable in various ways, so much data is
  available for student analysis

6
Misconceptions Based On Students Pretests
7
Historical Introduction (Regarding Galaxies)

• Reading that addresses key stages regarding the
  existence of other galaxies
• Geocentric view of Aristotle, Ptolemy, medieval
  Europe
• Heliocentric model of Copernicus and Galileo
• Kant and island universes, Charles Messiers
  accidental discovery of galaxies in the 18th
  century
• Photography and the development of astrophysics,
  William Herschels mapping of galaxies in the
  19th century
• (Facets of understanding to assess in
  future-empathy and perspective)

8
Model Development By Student Of Movement Of
Galaxies

• Students perform spectral analysis of galaxies
• Using data of Vesto Slipher (1911- who noticed
  light emitted from galaxies shifted red) and
  current data of spectral emissions of stars
  versus known spectral emissions of elements in
  lab
• Students will analyze for patterns and offer
  explanations for phenomena
• Discussion about already-familiar Doppler Effect
  and implication of data, especially in terms of
  redshift/velocity correlation (greater
  redshifthigher velocity)

9
Continued Building Of Expansion Of Universe Model

• Students measure distance to galaxies based on
  measurements of cepheids as standard candles of
  brightness
• Then students perform analysis of Hubbles data,
  identify patterns, offer explanations
• Hopefully, students recognize relationship of
  distance of galaxy vs. redshift/velocity (the
  more distant the galaxy, the greater its
  redshift, the higher the velocity)expansion of
  the universe

10
Calculating Age Of Universe From Expanding
Universe Inferences

• Inference of Lemaitre (1927) that since galaxies
  are moving apart, must have been closer in the
  past in more compressed state
• Assuming speed has been constant, and knowing
  distances of galaxies, can calculate when motion
  began, thus age of universe
• Calculation by students (tD/V)
• Hubble law relates velocity to distance (VDH)
• So, tD/DH
• t1/H
• t15 billion years

11
Developing The Big Bang Model

• Hubble Constant is Holy Grail for
  cosmologistspossible to estimate age if
  universethere must BE age of universe
• In addition, discovery of background radiation
  adds evidence in support of model (this can be
  presented to students as story of serendipitous
  discovery)
• The Steady State model, having no way to account
  for this radiation, does not prove as valid

12
Most Current Theories In Cosmology Are Variants
Of The Big Bang Model

• Understanding of universe reliant upon
  observatonal data made possible by technology
  such as HST, but how do cosmologists test their
  various models?

13
Theory Combined With Data Allows For Computer
SimulationOf Things Not Directly Observable

• NSF project, the Grand Challenge Cosmology
  Consortium, tests models of the cosmos
• Utilizes high perfromance computing and
  communications
• Is joint venture of cosmologists, astrophysicists
  and computer scientists in the US, coordinated by
  U of Illinois
• Provides AMAZING website that students can visit
  to learn about the project/technology, witness
  computer simulations of models of the Big Bang,
  watch movies of cosmologists at work and
  discussing their projects, and pose questions to
  current scientists in the field.

14
The Results Of Such An Approach

• Can then be compared to observations available in
  the future as technology is developed to better
  make such observations

15
A Possible Activity To Develop

• Comparing current data from HST or other source
  with simulation from GCCC
• (Testing of facets explanation, interpretation,
  application)