Introduction to the Universe

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Introduction to the Universe
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Related Goals

• Appreciating science in general, and astronomy in
  specific.
• Understanding how knowledge is gained and be
  critical of what you see and hear. You will begin
  to ask How can we test that? when forming
  hypotheses or How do we know that? when reading
  new information.
• Developing a working knowledge of the scientific
  method and how to apply it to real world
  situations.
• Critically analyzing and evaluating information,
  scientific or otherwise

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Related Outcomes

• Learn some simple astronomical nomenclature/termin
  ology
• Learn about some problems astronomers and
  astrophysicists are trying to solve, and
  understand the methods scientists are using to
  try to solve these problems.
• Develop a sense of what scientists know about the
  overall universe, its constituents, and our
  location

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Topics in this presentation

• Astronomical numbers
• Light travel time
• Composition of universe
• Why the composition changes
• What causes the change?
• Sizes, distances, and ages
• Motions
• Expanding universe, how we measure age

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Learning Objectives

• Know some ages distances
• Distinguish different types of large quantities
• Understand the consequences of light traveling
  over large distances

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Astronomical numbers

• 1 million _________ 10_. 1 million sec
  ________
• 1 billion __________ 10_ (aka. Giga or G). 1
  giga-sec
• _____________.
• 1 light sec ________________________________
• _________ _____________. Almost to ________
• 1 light year _______________________________
• TRIVIA 1 light year ____________________.
• Nearest star to Sun _______________ away.
• The Sun, all 8 planets are about _________ old.
• How many years is that?
• Universe everything in it is _________ (some
  things werent born at the beginning, so are
  younger)

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Calif. School Science Standards for Earths age
life development

• From California Science Standards, grade 6
• Students know that evidence from geologic layers
  and radioactive dating indicates Earth is
  approximately 4.6 billion years old and that life
  on this planet has existed for more than 3
  billion years.
• Newest evidence life probably started 3.5
  billion years ago, maybe even earlier (4 Gyr?).
• And from the high school standards
• Students know the evidence from Earth and moon
  rocks indicates that the solar system was formed
  from a nebular cloud of dust and gas
  approximately 4.6 billion years ago.
• The standards should include evidence from
  meteorites (space rocks that landed on Earth)

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Astronomers can detect a galaxy that is 10
billion light-years away.

1. True
2. False

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Finding baby senior citizen galaxies

• Talk to your neighbor for 1 minute and answer
  these
• Where would astronomers need to look to find
  galaxies in their earliest stages of life
  (babies)?
• Where would we find galaxies in their later
  stages (senior citizens)?

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Light years and observations

• Like letter through post office
• Letters from far away take ______________
• We receive ancient letters
• Letters from Los Angeles ______________
• We receive _________ letters
• FOR MORE HELP
• See figure 1.5 on p. 9
• Lecture Tutorial workbook Looking at Distant
  Objects, page 131.

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Furthest things seen

• As of 4/29/2009, the furthest object ever seen by
  astronomers is a Gamma Ray Burst (giant star
  explosion, hypernova) 13.035 billion light
  years away. Dist measured by redshift 8.2
• Occurred only 630 million years after the Big
  Bang. Probably a 1st generation HUGE star that
  died.
• Gigantic early generation stars make a GRB, which
  are probably a hypernova big supernova with
  powerful jets at poles
• Merely large or newer stars only make a
  supernova
• We see LIGHT leftover from the Big Bang, only
  380,000 yrs after the Big Bang.

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California Elementary School Science Standards
for atoms

• From California Science Standards, grade 5
• Students know that each element is made of one
  kind of atom and that the elements are organized
  in the periodic table by their chemical
  properties.

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Learning Objectives

• What is the universe composed of?
• How do we know?
• Is the composition changing? Why or why not?

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What the universe is made of how we know. Part
1.

• Things in the universe
• ____________
• _______________such as _______________
• _________(and other stuff) ______________
• ___________________________________
• Analyzing their __________(chapter 5), we
  discover, all of these are made of
• ___________(often _____) ____
• ___________(often inert _________) ____
• ____________
• List your favorites
• except not ________________________are.

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What the universe is made of how we know. Part
2a.

• Astronomers studied motions of ___________
  ______________________________________
• _________? must be ___________inside galaxies
• __________________________________
• _______________gravity from _______________
• _________________
• Existence hypothesized in 1933, Fritz Zwicky _at_
  CIT
• Vera Rubin gathered first STRONG evidence
  described above in 1970s. Shes still doing
  astronomy today!

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What the universe is made of how we know. Part
2b.

• Then, studying _______, found __________ in
  MANY other places
• Halos of galaxies
• Inside around galaxy clusters
• especially in center of clusters
• Based on _____________ there is ________more
  __________than regular matter!
• H, He, etc (_____________) are only _____ of
  stuff
• Dark matter is _____ of stuff
• We know its not _________________
• We know some properties of dark matter _______
  ________(how it clumps with elements, called
  bias)

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What the universe is made of how we know. Part
3.

• Measure ________________________________.
• (more on this soon)
• In 1998-99, multiple researchers discovered _____
  _____________________________than predicted
• Discovered by seeing supernovas in distant
  galaxies
• Confirmed by studying ____________________________
  _
• Universe expands faster today than in the past
• ____________________________________
• __________accounts for __ of the universes
  mass-energy. Matter/______ (including ____)
  only is __.

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Another visual of universes composition
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Normal matter

• Everything you know about is made of a few
  ______________________
• __________________________________________
• Most things are _______________________
• _______________________________________
• Science tells us right after the Big Bang, the
  universe ________________________
• ______________________________________
• TINY bit of 1-2 more.
• Where did everything else come from?
• Book calls it _________. See pages 6-7.
• Only __________________________. But thats
  enough to ______________________, luckily.

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Calif. Elementary School Science Standards for
atoms compounds

• From California Science Standards, grade 8
• Students know the structure of the atom and know
  it is composed of protons, neutrons, and
  electrons.
• Students know that compounds are formed by
  combining two or more different elements and that
  compounds have properties that are different from
  their constituent elements.
• And from the high school standards
• Students know the evidence indicating that all
  elements with an atomic number greater than that
  of lithium have been formed by nuclear fusion in
  stars.

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Learning Objectives

• Know some ages distances
• Put the ages and distances into perspective with
  other, more familiar things
• Understand motions on Earth, of Earth and of the
  Solar System

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Ages of a few things

• When things formed
• The Big Bang ____________________ ago
• The Sun Earth ________________ ago
• The Milky Way galaxy _____________ years ago
• See the calendar discussion on page 14.

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Sizes Distances

• Planet order sizes with hands
• In the Voyage scale model, __________
• Sun is the size of ___________________
• __________________________________________________
  ______________________
• __________________________________________________
  ______________________
• Jupiter is
• Pluto is
• Nearest star is named , size dist
• Size of Milky Way is
• Light travel times to these objects

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California Elementary School Science Standards
for solar system

• From California Science Standards, grade 5
• Students know the Sun, an average star, is the
  central and largest body in the solar system and
  is composed primarily of hydrogen and helium.
• Students know the solar system includes the
  planet Earth, the Moon, the Sun, eight other
  planets and their satellites, and smaller
  objects, such as asteroids and comets.
• Satellites moons

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California Elementary School Science Standards
for solar system

• And from the high school standards
• Students know the evidence indicating that the
  planets are much closer to Earth than the stars
  are.
• Students know the Sun is a typical star and is
  powered by nuclear reactions, primarily the
  fusion of hydrogen to form helium.
• Students know the solar system is located in an
  outer edge of the disc-shaped Milky Way galaxy,
  which spans 100,000 light years.
• Students know galaxies are made of billions of
  stars and comprise most of the visible mass of
  the universe.
• Not true anymore. Most visible mass seems to be
  located in the center of galaxy clusters.

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Motions

• Daily motion Earths rotation once per __
• Speed varies ___ for Santa, __________________
• Yearly motion Earths revolution once per __
• Distance 1AU ____
• Speed average _____________mph
• Direction ________________________________.
• Sun ___________________________ 230 Myr
• 28,000 ly radius, speed 500,000 mph
• Studying this motion ? ______________________
• Galaxies moving relative to each other.
• _________________________________________

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Do all continents on Earth take 24 hours to make
one circle around the Earth?

1. Yes
2. No

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Galaxies outside the Local Group are moving

1. Towards us
2. Away from us
3. Randomly towards away

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Learning Objectives

• Understand the nature of the expanding universe
  and how we know its expanding
• Hubbles Law
• Interpret expansion of universe to determine a
  fundamental property
• Car universe
• Understand what we need to measure about the
  universe to determine its age

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Expanding universe means objects are getting
_________?

1. Further apart
2. Bigger
3. Both further apart and bigger

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Expanding universe

• Expansion refers to __________________________
• Objects dont grow because
• ___________________________________________
• Examples ______________________________________.
• We see _______________________
• Speed away from us depends on ______________
• Objects ____________ are moving twice as fast
• Objects _____________ are moving
  _________________
• This rule is now called ____________________
• Lets see how __________________ works with cars

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Car expanding universe

• Make a chart like the one I put on the board
  (next slide has room)
• Car 1 is 60 miles away and travels 30 mph
• Car 2 is 120 miles away. How fast is it moving if
  it follows Hubbles Law?
• Car 3 is 240 miles away. How fast?
• How long since Car 1 left you?
• Car 2?
• Car 3?
• How old is the car universe?
• This is exactly what we see with galaxies, except
  the time is _________ years.

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Chart goes here
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California Elementary School Science Standards
for astronomy

• From California Science Standards, grade 8
• Students know galaxies are clusters of billions
  of stars and may have different shapes.
• Students know that the Sun is one of many stars
  in the Milky Way galaxy and that stars may differ
  in size, temperature, and color.
• Students know how to use astronomical units and
  light years as measures of distances between the
  Sun, stars, and Earth.
• Students know that stars are the source of light
  for all bright objects in outer space and that
  the Moon and planets shine by reflected sunlight,
  not by their own light.
• (technically, Moon planets shine by scattered
  light)
• Students know the appearance, general
  composition, relative position and size, and
  motion of objects in the solar system, including
  planets, planetary satellites, comets, and
  asteroids.

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Learning Objectives

• Know some ages distances
• Distinguish different types of large quantities
• Put the ages and distances into perspective with
  other, more familiar things
• Understand the consequences of light traveling
  over large distances
• What is the universe composed of?
• How do we know?
• Is the composition changing? Why or why not?
• Understand motions on Earth, of Earth and of the
  Solar System
• Understand the nature of the expanding universe
  and how we know its expanding
• Hubbles Law
• Interpret expansion of universe to determine a
  fundamental property
• Car universe
• Understand what we need to measure about the
  universe to determine its age

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Summary chapter 1

• Astronomical numbers
• Light travel time
• Composition of universe
• Why the composition changes
• What causes the change?
• Sizes, distances, and ages
• Motions
• Expanding universe, how we measure age