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Galaxies and the Galaxies and the UniverseUniverseChap. 31Chap. 31Chap. 31Chap. 31
The Milky Way 31.1
Other Galaxies in the Universe 31.2
Cosmology 31.3
The Milky WayThe Milky Way
ObjectivesObjectives
• determine the size and shape of the Milky Way, as well as Earth’s location within it.• describe how the Milky Way formed.
I.I. Discovering the Milky WayDiscovering the Milky WayA.A. Distances to clusters determined Distances to clusters determined
using using variable starsvariable stars..
I.I. Discovering the Milky WayDiscovering the Milky WayA.A. Distances to clusters determined Distances to clusters determined
using using variable starsvariable stars..
Stars in the ‘giant’ branch of Stars in the ‘giant’ branch of HR diagram that pulsate in HR diagram that pulsate in brightnessbrightness
Variable StarsVariable Stars
I.I. Discovering the Milky WayDiscovering the Milky WayA.A. Distances to clusters determined Distances to clusters determined
using using variable starsvariable stars..
Brightness pulsates between 1.5 hours and 1 dayBrightness pulsates between 1.5 hours and 1 day
1.1. RR Lyrae variablesRR Lyrae variables
I.I. Discovering the Milky WayDiscovering the Milky WayA.A. Distances to clusters determined Distances to clusters determined
using using variable starsvariable stars..
Brightness pulsates between 1 and 100 daysBrightness pulsates between 1 and 100 days
1.1. RR Lyrae variablesRR Lyrae variables
2.2. Cepheid variablesCepheid variables
(graph this)(graph this)
I.I. Discovering the Milky WayDiscovering the Milky WayA.A. Distances to clusters determined Distances to clusters determined
using using variable starsvariable stars..
The larger the period (time) of pulsation the The larger the period (time) of pulsation the greater the luminosity. greater the luminosity. (graph this)(graph this)
1.1. RR Lyrae variablesRR Lyrae variables
2.2. Cepheid variablesCepheid variables
3.3. These stars make good standard These stars make good standard candlescandles
Calculating distanceCalculating distance
If a star is really bright If a star is really bright (__________ magnitude) but it (__________ magnitude) but it appears to be dim (_________ appears to be dim (_________ magnitude), you know it’s far. magnitude), you know it’s far. The dimmer it looks the farther The dimmer it looks the farther it is.it is.
II.II. Locating the Center of the Locating the Center of the GalaxyGalaxy
II.II. Locating the Center of the Locating the Center of the GalaxyGalaxy
A.A. Globular clusters are centered Globular clusters are centered around a point about 28,000 ly awayaround a point about 28,000 ly away
II.II. Locating the Center of the Locating the Center of the GalaxyGalaxy
A.A. Globular clusters are centered Globular clusters are centered around a point about 28,000 ly awayaround a point about 28,000 ly away
B.B. Center has high density of starsCenter has high density of stars
II.II. Locating the Center of the Locating the Center of the GalaxyGalaxy
A.A. Globular clusters are centered Globular clusters are centered around a point about 28,000 ly awayaround a point about 28,000 ly away
B.B. Center has high density of starsCenter has high density of stars
C.C. Center is toward Sagittarius Center is toward Sagittarius constellationconstellation
http://www.esa.int
III.III. Shape of Milky WayShape of Milky WayA.A. The MW is a flattened disk shapeThe MW is a flattened disk shape
III.III. Shape of Milky WayShape of Milky WayA.A. The MW is a flattened disk shapeThe MW is a flattened disk shape
B.B. Galactic center (nucleus) surrounded Galactic center (nucleus) surrounded by nuclear bulgeby nuclear bulge
III.III. Shape of Milky WayShape of Milky WayA.A. The MW is a flattened disk shapeThe MW is a flattened disk shape
B.B. Galactic center (nucleus) surrounded Galactic center (nucleus) surrounded by nuclear bulgeby nuclear bulge
C.C. A spherical-shaped halo containing A spherical-shaped halo containing older stars surrounds the disk.older stars surrounds the disk.
III.III. Shape of Milky WayShape of Milky WayD.D. Four major spiral arms (and Four major spiral arms (and
several minor spiral arms) have several minor spiral arms) have been identifiedbeen identified
IV.IV. Mass of the Milky WayMass of the Milky Way
IV.IV. Mass of the Milky WayMass of the Milky WayA.A. Might be found by measuring Might be found by measuring
luminosityluminosity
Remember that luminosity is related to mass. Remember that luminosity is related to mass. Stars that are bigger are also _________.Stars that are bigger are also _________.
IV.IV. Mass of the Milky WayMass of the Milky WayA.A. Might be found by measuring Might be found by measuring
luminosityluminosity
B.B. Mass is usually found by using our Mass is usually found by using our orbital speedorbital speed
Calculating MassCalculating Mass
(M(M11 + M + M22)P)P22 = a = a33 Kepler’s 3 Kepler’s 3rdrd law law
MM11 is sun’s mass (measured in “sun masses”) is sun’s mass (measured in “sun masses”)
MM22 is universe’s mass (measured in “sun masses”) is universe’s mass (measured in “sun masses”)
PP is orbital period (years) = 240 million y is orbital period (years) = 240 million y
aa is distance (in AU) is distance (in AU)
1 ly = 63,200 AU1 ly = 63,200 AU
IV.IV. Mass of the Milky WayMass of the Milky WayA.A. Might be found by measuring Might be found by measuring
luminosityluminosity
B.B. Mass is usually found by using our Mass is usually found by using our orbital speedorbital speed
C.C. Since the MW is about 100 billion Since the MW is about 100 billion times the mass of the Sun, an average times the mass of the Sun, an average sized star, the MW must contain sized star, the MW must contain about about stars. stars.
IV.IV. Mass of the Milky WayMass of the Milky WayA.A. Might be found by measuring Might be found by measuring
luminosityluminosity
B.B. Mass is usually found by using our Mass is usually found by using our orbital speedorbital speed
C.C. Since the MW is about 100 billion Since the MW is about 100 billion times the mass of the Sun, an average times the mass of the Sun, an average sized star, the MW must contain sized star, the MW must contain about about 100 billion100 billion stars. stars.
V.V. Mass of the Center of the Mass of the Center of the Milky WayMilky Way
A.A. Stars near the center orbit Stars near the center orbit center very fast – this indicates center very fast – this indicates a very a very center center
V.V. Mass of the Center of the Mass of the Center of the Milky WayMilky Way
A.A. Stars near the center orbit Stars near the center orbit center very fast – this indicates center very fast – this indicates a very a very massivemassive center center
V.V. Mass of the Center of the Mass of the Center of the Milky WayMilky Way
A.A. Stars near the center orbit Stars near the center orbit center very fast – this indicates center very fast – this indicates a very a very massivemassive center center
B.B. It is thought that there is a It is thought that there is a super black hole at the center of super black hole at the center of our galaxyour galaxy
This center is about 2.6 million times the This center is about 2.6 million times the Sun’s massSun’s mass
VI.VI. Age of Stars in Milky WayAge of Stars in Milky Way
VI.VI. Age of Stars in Milky WayAge of Stars in Milky WayA.A. Young stars form in the arms of Young stars form in the arms of
the MWthe MW
VI.VI. Age of Stars in Milky WayAge of Stars in Milky WayA.A. Young stars form in the arms of Young stars form in the arms of
the MWthe MW
B.B. Old stars are found in the Old stars are found in the halo/nuclear bulge.halo/nuclear bulge.
VII.VII. Formation of Milky WayFormation of Milky Way
VII.VII. Formation of Milky WayFormation of Milky WayA.A. MW was originally round.MW was originally round.
Notice the arrangement of the oldest stars.Notice the arrangement of the oldest stars.
VII.VII. Formation of Milky WayFormation of Milky WayA.A. MW was originally round.MW was originally round.
B.B. The MW cloud collapsed and The MW cloud collapsed and flattened into a disk shape.flattened into a disk shape.
The End
Other Galaxies – 30.2ObjectivesObjectives• Describe how
astronomers classify galaxies
• Identify how galaxies are organized into clusters and superclusters
• Describe the expansion of the universe
I.I. IdentifyingIdentifying
I.I. IdentifyingIdentifyingA.A. Astronomers saw other galaxies Astronomers saw other galaxies
before they knew what they were.before they knew what they were.
I.I. IdentifyingIdentifyingA.A. Astronomers saw other galaxies Astronomers saw other galaxies
before they knew what they were.before they knew what they were.
B.B. Edwin Hubble measured their Edwin Hubble measured their distances to confirm they were distances to confirm they were not in MW.not in MW.
He used variable stars to do it.He used variable stars to do it.
II.II. ClassifyingClassifying
II.II. ClassifyingClassifyingA.A. SpiralSpiral
M74 in pisces
““Cosmic Frisbee”Cosmic Frisbee”
II.II. ClassifyingClassifyingA.A. SpiralSpiral
1.1. Normal spirals (S)Normal spirals (S)
II.II. ClassifyingClassifyingA.A. SpiralSpiral
1.1. Normal spirals (S)Normal spirals (S)
2.2. Barred spirals (SB)Barred spirals (SB)
NGC 1300 – in EridanusNGC 1300 – in Eridanus
II.II. ClassifyingClassifyingA.A. SpiralSpiral
Type aType a represents tightly wound arm with bright represents tightly wound arm with bright nucleus.nucleus.
1.1. Normal spirals (S)Normal spirals (S)
2.2. Barred spirals (SB)Barred spirals (SB)
3.3. These are further divided by These are further divided by how tightly wound arms are (a, how tightly wound arms are (a, b, c)b, c)
II.II. ClassifyingClassifyingA.A. SpiralSpiral
B.B. EllipticalsEllipticals
““Cosmic Football”Cosmic Football”
II.II. ClassifyingClassifyingA.A. SpiralSpiral
B.B. EllipticalsEllipticals1.1. Divided from E0 to E7.Divided from E0 to E7.
II.II. ClassifyingClassifyingA.A. SpiralSpiral
B.B. EllipticalsEllipticals1.1. Divided from E0 to E7.Divided from E0 to E7.
2.2. E7 has a large ratio of major E7 has a large ratio of major axis/minor axis, E0 is circular.axis/minor axis, E0 is circular.
II.II. ClassifyingClassifyingA.A. SpiralSpiral
B.B. EllipticalsEllipticals
C.C. Irregular Galaxies (Irr)Irregular Galaxies (Irr)
http://www.nasa.gov
II.II. ClassifyingClassifyingD.D. MassesMasses
II.II. ClassifyingClassifyingD.D. MassesMasses
1.1. Dwarf ellipticals have few stars Dwarf ellipticals have few stars (about 1 million).(about 1 million).
II.II. ClassifyingClassifyingD.D. MassesMasses
1.1. Dwarf ellipticals have few stars Dwarf ellipticals have few stars (about 1 million).(about 1 million).
2.2. Large spirals, like MW, have Large spirals, like MW, have about 100 million stars.about 100 million stars.
II.II. ClassifyingClassifyingD.D. MassesMasses
1.1. Dwarf ellipticals have few stars Dwarf ellipticals have few stars (about 1 million).(about 1 million).
2.2. Large spirals, like MW, have Large spirals, like MW, have about 100 million stars.about 100 million stars.
3.3. Giant ellipticals have mass of 100 Giant ellipticals have mass of 100 trillion trillion xx the sun. the sun.
III.III. Groups & ClustersGroups & Clusters
III.III. Groups & ClustersGroups & ClustersA.A. Local groupLocal group
M33 - M33 - member of the local groupmember of the local group
III.III. Groups & ClustersGroups & Clusters
1.1. Includes Milky WayIncludes Milky Way
A.A. Local groupLocal group
http://www.spacetoday.org
III.III. Groups & ClustersGroups & Clusters
1.1. Includes Milky WayIncludes Milky Way
2.2. About 35 known members About 35 known members including Andromeda and including Andromeda and several dwarf galaxies.several dwarf galaxies.
A.A. Local groupLocal group
http://www.via.ee
III.III. Groups & ClustersGroups & Clusters
1.1. Includes Milky WayIncludes Milky Way
2.2. About 35 known members About 35 known members including Andromeda and including Andromeda and several dwarf galaxies.several dwarf galaxies.
3.3. It’s about 2 million ly acrossIt’s about 2 million ly across
A.A. Local groupLocal group
III.III. Groups & ClustersGroups & ClustersA.A. Local groupLocal group
B.B. There are clusters much bigger There are clusters much bigger than local group (ex. Virgo)than local group (ex. Virgo)
http://www.randybrewer.net
III.III. Groups & ClustersGroups & ClustersA.A. Local groupLocal group
B.B. There are clusters much bigger There are clusters much bigger than local group (ex. Virgo)than local group (ex. Virgo)
C.C. Mass of clusters are bigger than Mass of clusters are bigger than the sum of the parts.the sum of the parts.
This is evidence for existence of dark matterThis is evidence for existence of dark matter
IV.IV. The Expanding UniverseThe Expanding Universe
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
B.B. ““Red shift”Red shift”
Light waves are stretched out due to relative motion Light waves are stretched out due to relative motion of source and observer away from each other.of source and observer away from each other.
Red ShiftRed Shift
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
B.B. ““Red shift”Red shift”1.1. Indicates galaxy is moving away Indicates galaxy is moving away
from usfrom us
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
B.B. ““Red shift”Red shift”1.1. Indicates galaxy is moving away Indicates galaxy is moving away
from usfrom us
2.2. Hubble determined the degree of Hubble determined the degree of red shift depends on the distance red shift depends on the distance awayaway
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
B.B. ““Red shift”Red shift”1.1. Indicates galaxy is moving away Indicates galaxy is moving away
from usfrom us
2.2. Hubble determined the degree of Hubble determined the degree of red shift depends on the distance red shift depends on the distance awayaway
3.3. All galaxies are moving away All galaxies are moving away from all other galaxies (not just from all other galaxies (not just Earth)Earth)
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
B.B. ““Red shift”Red shift”
C.C. Hubble’s lawHubble’s law
vv = = HdHd
IV.IV. The Expanding UniverseThe Expanding UniverseA.A. Discovered by Hubble in 1929Discovered by Hubble in 1929
B.B. ““Red shift”Red shift”
C.C. Hubble’s lawHubble’s law
vv = = HdHdvelocity (km/s)velocity (km/s)
Distance (Mpc)Distance (Mpc)
Hubble’s constantHubble’s constant
V.V. Active GalaxiesActive Galaxies
V.V. Active GalaxiesActive GalaxiesA.A. Radio GalaxiesRadio Galaxies
NGC 5128 - NGC 5128 - Radio galaxyRadio galaxy
V.V. Active GalaxiesActive GalaxiesA.A. Radio GalaxiesRadio Galaxies
1.1. Two lobes connected by jets of Two lobes connected by jets of hot gas.hot gas.
V.V. Active GalaxiesActive GalaxiesA.A. Radio GalaxiesRadio Galaxies
1.1. Two lobes connected by jets of Two lobes connected by jets of hot gas.hot gas.
2.2. Observed by radio telescopes Observed by radio telescopes because they emit more radio because they emit more radio waves than visible light.waves than visible light.
Radio telescope
V.V. Active GalaxiesActive GalaxiesB.B. Active Galactic Nuclei (AGN)Active Galactic Nuclei (AGN)
V.V. Active GalaxiesActive GalaxiesB.B. Active Galactic Nuclei (AGN)Active Galactic Nuclei (AGN)
1.1. Highly energetic galactic coresHighly energetic galactic cores
V.V. Active GalaxiesActive GalaxiesB.B. Active Galactic Nuclei (AGN)Active Galactic Nuclei (AGN)
1.1. Highly energetic galactic coresHighly energetic galactic cores
2.2. Output of energy variesOutput of energy varies
VI.VI. QuasarsQuasars
VI.VI. QuasarsQuasarsA.A. Like other galaxies, but these are Like other galaxies, but these are
strong radio emitters.strong radio emitters.
VI.VI. QuasarsQuasarsA.A. Like other galaxies, but these are Like other galaxies, but these are
strong radio emitters.strong radio emitters.
B.B. Create emission lines, instead of Create emission lines, instead of absorption lines.absorption lines.
Absorption spectrumAbsorption spectrum
Emission spectrumEmission spectrum
VI.VI. QuasarsQuasarsA.A. Like other galaxies, but these are Like other galaxies, but these are
strong radio emitters.strong radio emitters.
B.B. Create emission lines, instead of Create emission lines, instead of absorption lines.absorption lines.
C.C. These objects have a very large These objects have a very large red shift (so they are very far red shift (so they are very far away).away).
VII.VII. Looking back in timeLooking back in time
VII.VII. Looking back in timeLooking back in timeA.A. We study stars/galaxies as they We study stars/galaxies as they
were.were.
VII.VII. Looking back in timeLooking back in timeA.A. We study stars/galaxies as they We study stars/galaxies as they
were.were.
B.B. Seeing quasars that are very far Seeing quasars that are very far (old) suggests a possible ‘quasar (old) suggests a possible ‘quasar stage’ during universe history.stage’ during universe history.
The End
Cosmology – 31.3ObjectivesObjectives• Explain the different
theories about the formation of the universe
• Describe the possible outcomes of universal expansion
I.I. ModelsModels
I.I. ModelsModelsA.A. Steady State TheorySteady State Theory
I.I. ModelsModelsA.A. Steady State TheorySteady State Theory
1.1. The Universe does not change The Universe does not change with time.with time.
I.I. ModelsModelsA.A. Steady State TheorySteady State Theory
1.1. The Universe does not change The Universe does not change with time.with time.
2.2. The Universe had no beginningThe Universe had no beginning
I.I. ModelsModelsA.A. Steady State TheorySteady State Theory
1.1. The Universe does not change The Universe does not change with time.with time.
2.2. The Universe had no beginningThe Universe had no beginning
3.3. The Density stays constantThe Density stays constant
I.I. ModelsModelsA.A. Steady State TheorySteady State Theory
1.1. The Universe does not change The Universe does not change with time.with time.
2.2. The Universe had no beginningThe Universe had no beginning
3.3. The Density stays constantThe Density stays constant
4.4. As Universe expands, new As Universe expands, new material is created and addedmaterial is created and added
I.I. ModelsModelsB.B. Big Bang TheoryBig Bang Theory
I.I. ModelsModelsB.B. Big Bang TheoryBig Bang Theory
1.1. All matter began at a point initiallyAll matter began at a point initially
I.I. ModelsModelsB.B. Big Bang TheoryBig Bang Theory
1.1. All matter began at a point initiallyAll matter began at a point initially
2.2. The matter and space of our Universe The matter and space of our Universe has been expanding ever sincehas been expanding ever since
II.II. Cosmic Background Cosmic Background Radiation (CBR)Radiation (CBR)
II.II. Cosmic Background Cosmic Background Radiation (CBR)Radiation (CBR)A.A. Low-level microwave radiationLow-level microwave radiation
II.II. Cosmic Background Cosmic Background Radiation (CBR)Radiation (CBR)A.A. Low-level microwave radiationLow-level microwave radiation
B.B. This radiation comes from all This radiation comes from all directionsdirections
II.II. Cosmic Background Cosmic Background Radiation (CBR)Radiation (CBR)A.A. Low-level microwave radiationLow-level microwave radiation
B.B. This radiation comes from all This radiation comes from all directionsdirections
C.C. CBR is associated with cool CBR is associated with cool temperature (2.735 K)temperature (2.735 K)
II.II. Cosmic Background Cosmic Background Radiation (CBR)Radiation (CBR)A.A. Low-level microwave radiationLow-level microwave radiation
B.B. This radiation comes from all This radiation comes from all directionsdirections
C.C. CBR is associated with cool CBR is associated with cool temperature (2.735 K)temperature (2.735 K)
D.D. The steady state theory does not The steady state theory does not explain CBRexplain CBR
II.II. Cosmic Background Cosmic Background Radiation (CBR)Radiation (CBR)E.E. This has been mapped by This has been mapped by
satellites.satellites.
III.III. Big Bang ModelBig Bang Model
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while pulls inward pulls inward
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while gravitygravity pulls inward pulls inward
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while gravitygravity pulls inward pulls inward
B.B. The rate of expansion is slowingThe rate of expansion is slowing
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while gravitygravity pulls inward pulls inward
B.B. The rate of expansion is slowingThe rate of expansion is slowing
C.C. Possible OutcomesPossible Outcomes
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while gravitygravity pulls inward pulls inward
B.B. The rate of expansion is slowingThe rate of expansion is slowing
C.C. Possible OutcomesPossible Outcomes
1.1. Open Universe –Open Universe –
Expansion of Universe never stopsExpansion of Universe never stops
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while gravitygravity pulls inward pulls inward
B.B. The rate of expansion is slowingThe rate of expansion is slowing
C.C. Possible OutcomesPossible Outcomes
1.1. Open Universe –Open Universe –
2.2. Closed Universe – Closed Universe –
Expansion stops and becomes a contractionExpansion stops and becomes a contraction
III.III. Big Bang ModelBig Bang ModelA.A. Momentum carries material Momentum carries material
outward while outward while gravitygravity pulls inward pulls inward
B.B. The rate of expansion is slowingThe rate of expansion is slowing
C.C. Possible OutcomesPossible Outcomes
1.1. Open Universe –Open Universe –
2.2. Closed Universe – Closed Universe –
3.3. Flat Universe – Flat Universe –
Expansion slows to halt in infinite amt. of timeExpansion slows to halt in infinite amt. of time
III.III. Big Bang ModelBig Bang ModelD.D. Critical DensityCritical Density
1.1. The outcome of the Universe The outcome of the Universe depends on the amount (density) of depends on the amount (density) of material in it.material in it.
III.III. Big Bang ModelBig Bang ModelD.D. Critical DensityCritical Density
1.1. The outcome of the Universe The outcome of the Universe depends on the amount (density) of depends on the amount (density) of material in it.material in it.
a)a) Less than critical density (10Less than critical density (10-26-26 kg/mkg/m33) results in ) results in open Universe.open Universe.
III.III. Big Bang ModelBig Bang ModelD.D. Critical DensityCritical Density
1.1. The outcome of the Universe The outcome of the Universe depends on the amount (density) of depends on the amount (density) of material in it.material in it.
a)a) Less than critical density (10Less than critical density (10-26-26 kg/mkg/m33) results in ) results in open Universe.open Universe.
b)b) More than critical density More than critical density means means closed Universeclosed Universe
III.III. Big Bang ModelBig Bang ModelD.D. Critical DensityCritical Density
1.1. The outcome of the Universe The outcome of the Universe depends on the amount (density) of depends on the amount (density) of material in it.material in it.
a)a) Less than critical density (10Less than critical density (10-26-26 kg/mkg/m33) results in ) results in open Universe.open Universe.
b)b) More than critical density More than critical density means means closed Universeclosed Universe
c)c) Equal to Critical density means Equal to Critical density means flat Universeflat Universe
III.III. Big Bang ModelBig Bang ModelD.D. Critical DensityCritical Density
1.1. The outcome of the Universe The outcome of the Universe depends on the amount (density) of depends on the amount (density) of material in it.material in it.
d)d) Observations show less than Observations show less than critical density, (but there is critical density, (but there is dark matterdark matter))
IV.IV. Decrease of Rate of Decrease of Rate of ExpansionExpansion
IV.IV. Decrease of Rate of Decrease of Rate of ExpansionExpansion
A.A. This could be used to tell the This could be used to tell the outcome of the Universeoutcome of the Universe
IV.IV. Decrease of Rate of Decrease of Rate of ExpansionExpansion
A.A. This could be used to tell the This could be used to tell the outcome of the Universeoutcome of the Universe
B.B. Universe’s expansion should be Universe’s expansion should be getting slowergetting slower
IV.IV. Decrease of Rate of Decrease of Rate of ExpansionExpansion
A.A. This could be used to tell the This could be used to tell the outcome of the Universeoutcome of the Universe
B.B. Universe’s expansion should be Universe’s expansion should be getting slowergetting slower
C.C. We observed it’s actually We observed it’s actually expanding fasterexpanding faster
IV.IV. Inflationary UniverseInflationary Universe
Universe began with a fluctuation in expansion. Universe began with a fluctuation in expansion. For a brief instant its rate of expansion increasedFor a brief instant its rate of expansion increased
Calculating AgeCalculating Age
Calculate the number of years since Calculate the number of years since expansion of the Universe using expansion of the Universe using Hubble’s constant: 1/H = timeHubble’s constant: 1/H = time
H = 50 km/s / Mpc or H = 100 km/s / MpcH = 50 km/s / Mpc or H = 100 km/s / Mpc
1 pc = 3.1 x 101 pc = 3.1 x 101313 km km
‘‘mega’ (M) = 1 000 000 unitsmega’ (M) = 1 000 000 units
The End