Transcript No Slide Title

Charles Hakes
Fort Lewis College
1
Outline
• Final next Monday (9:45).
• bring a scantron; good eraser, or extra
scantron; sharp pencils
• calculator
• Dark Energy
• Review
Charles Hakes
Fort Lewis College
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Probable Job Opportunity
• The Academic Success Program
regularly funds Astronomy Tutors/
Study Group leaders. If you might be
interested in this for next fall, please
let me know via email.
Charles Hakes
Fort Lewis College
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Test Topics (recent/new)
• Chapter 13 - Neutron Stars and Black
Holes
• Shwarzschild radius
• Chapter 14 - The Milky way
•
•
•
•
Size and Shape
Spectroscopic parallax
Cepheid variables
Mass and dark matter
Charles Hakes
Fort Lewis College
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Test Topics (recent/new)
• Chapter 15 - Normal and Active Galaxies
•
•
•
•
Standard Candles
Tully-Fisher relationship
Type I supernova
Quasars
• Chapter 16 - Hubble’s Law and Dark
Matter
• Hubble’s law
• Distance ladder
• Large scale structure
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Fort Lewis College
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Test Topics (recent/new)
• Chapter 17 - Cosmology
• Big Bang
• Age of the universe
• Critical density & fate of universe
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Fort Lewis College
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Chapter 17
Cosmology
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Fort Lewis College
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Chapter 17
Ultra Deep Field - more than 1000 galaxies are in this
picture. Total estimate for the universe - ~40,000,000,000.
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Fort Lewis College
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Cosmology
•
•
•
•
How big is the universe?
How long has it been here?
How did it start?
How long will it last?
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Fort Lewis College
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The Fate of the Universe
• Will it keep expanding forever?
• Will gravity cause it to collapse?
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Fort Lewis College
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Figure 17.5
Escape Velocity
• With enough
initial velocity, a
spacecraft will
“escape” from
the Earth
• With insufficient
velocity, gravity
will bring it back
to Earth.
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Fort Lewis College
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Figure 17.6
Model Universes
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Fort Lewis College
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The Fate of the Universe
• A high density universe will collapse again
into a Big Crunch.
• A low density universe will continue to
expand forever.
• Critical density - boundary between the two
cases. (9x10-27 kg/m3 = ~5 atoms/m3)
• The ratio of the actual density to the critical
density is called Wo, the critical density
parameter.
Charles Hakes
Fort Lewis College
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The Fate of the Universe
• If you can determine the density of the
universe, you can determine if there will be
a Big Crunch or not.
Charles Hakes
Fort Lewis College
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The Fate of the Universe
• If you can determine the density of the
universe, you can determine if there will be
a Big Crunch or not.
• However - most of the matter in the
universe is dark!
Charles Hakes
Fort Lewis College
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The Fate of the Universe
• If you can determine the density of the
universe, you can determine if there will be
a Big Crunch or not.
• However - most of the matter in the
universe is dark!
• Even with dark matter estimates, it appears
that Wo < 1.0, if that is all you look at...
Charles Hakes
Fort Lewis College
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The Accelerating Universe
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Fort Lewis College
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Figure 17.7
Accelerating Universe
Charles Hakes
Fort Lewis College
• If the universe is
“slowing down”
because of gravity,
distant objects (as seen
in the past) should be
moving faster.
• Recent measurements
show this is not the case
- something is
accelerating everything.
• That “something” is
called Dark Energy.
• This “dark energy” is
not understood at all.
18
Discovery 17-1
The Cosmological Constant
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Fort Lewis College
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Figure 17.8
Cosmic Age
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Fort Lewis College
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
http://www.newgrounds.com/portal/view/52
5347
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Fort Lewis College
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Current Status of the Universe
• Expanding (and accelerating!) - looks like
no big crunch for us.
• Composition - looks like Wo=1, the critical
density parameter.
• Normal Matter ~ 4%
• Mostly H and He
• Dark Matter ~23%
• Dark Energy ~73%
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Fort Lewis College
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Big Bang Events
• Inflation - needed to get a uniform density in the
universe. (<~10-32s!)
• Nucleosynthesis - most of the He (~25% of normal
matter) formed in the first 15 minutes of the
universe. The rest was left as H.
• Microwave Decoupling (atom formation) - once
electrons joined the nuclei, then photons were no
longer scattered and the universe became
transparent. After a few 10,000s of years.
• Large Scale Structure - normal matter “clumps”
around the dark matter.
• Finally acceleration by dark energy.
Charles Hakes
Fort Lewis College
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The concept that on the grandest of scales, the
universe is similar in appearance everywhere is:
A) general relativity.
B) special relativity.
C) homogeneity.
D) isotropy.
E) universality.
Charles Hakes
Fort Lewis College
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The concept that on the grandest of scales, the
universe is similar in appearance everywhere is:
A) general relativity.
B) special relativity.
C) homogeneity.
D) isotropy.
E) universality.
Charles Hakes
Fort Lewis College
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ADT
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Fort Lewis College
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How confident were you about your answers on
the Astronomy Diagnostic Test
A) very confident.
B) somewhat confident.
C) not very confident.
D) just guessing.
Charles Hakes
Fort Lewis College
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Why is it cold at the North Pole, even during
northern hemisphere summer?
1 - Because the “pole” itself doesn’t point very close to the
direction of the Sun
2 - Because there are fewer daylight hours at the pole than at
lower latitudes (e.g., Durango)
3 - Because of the high altitude at the pole
4 - Because the pole is further away from the Sun than lower
latitudes are (e.g., Durango)
Charles Hakes
Fort Lewis College
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Why is it cold at the North Pole, even during
northern hemisphere summer?
1 - Because the “pole” itself doesn’t point very close to the
direction of the Sun
2 - Because there are fewer daylight hours at the pole than at
lower latitudes (e.g., Durango)
3 - Because of the high altitude at the pole
4 - Because the pole is further away from the Sun than lower
latitudes are (e.g., Durango)
Charles Hakes
Fort Lewis College
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Star A has a parallax shift of 0.4 arc second
Star B has a parallax shift of 0.6 arc seconds
1:
2:
3:
4:
B is 1.5 times as far away as A
Star A is at a distance of 4 parsecs (pc)
Star B is at a distance of 1.66 parsecs (pc)
Star A is 0.4 times as far away as B
Charles Hakes
Fort Lewis College
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Star A has a parallax shift of 0.4 arc second
Star B has a parallax shift of 0.6 arc seconds
1:
2:
3:
4:
B is 1.5 times as far away as A
Star A is at a distance of 4 parsecs (pc)
Star B is at a distance of 1.66 parsecs (pc)
Star A is 0.4 times as far away as B
Charles Hakes
Fort Lewis College
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Which is correct?
1 - The new moon rises at noon.
2 - The first quarter moon rises at noon.
3 - The full moon rises at noon.
4 - The third quarter moon rises at noon.
Charles Hakes
Fort Lewis College
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Which is correct?
1 - The new moon rises at noon.
2 - The first quarter moon rises at noon.
3 - The full moon rises at noon.
4 - The third quarter moon rises at noon.
Charles Hakes
Fort Lewis College
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In Paris, France (50 degrees north latitude),
what is the longest day of the year?
1:
2:
3:
4:
March 21
June 21
September 21
December 21
Charles Hakes
Fort Lewis College
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In Paris, France (50 degrees north latitude),
what is the longest day of the year?
1:
2:
3:
4:
March 21
June 21
September 21
December 21
Charles Hakes
Fort Lewis College
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Where along the horizon does the Sun rise on
June 21 in Paris, France?
1:
2:
3:
4:
Due east
North of east
South of east
Can’t tell with information given
Charles Hakes
Fort Lewis College
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Where along the horizon does the Sun rise on
June 21 in Paris, France?
1:
2:
3:
4:
Due east
North of east
South of east
Can’t tell with information given
Charles Hakes
Fort Lewis College
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Where along the horizon does the Sun rise on
June 21 in Sydney, Australia?
1:
2:
3:
4:
Due east
North of east
South of east
Can’t tell with information given
Charles Hakes
Fort Lewis College
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Where along the horizon does the Sun rise on
June 21 in Sydney, Australia?
1:
2:
3:
4:
Due east
North of east
South of east
Can’t tell with information given
Charles Hakes
Fort Lewis College
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On December 21, in Durango, if there is a full
moon, where does it rise?
1:
2:
3:
4:
Due east
Almost due east (within 5 degrees)
South of east (by more than 5 degrees)
North of east (by more than 5 degrees)
Charles Hakes
Fort Lewis College
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On December 21, in Durango, if there is a full
moon, where does it rise?
1:
2:
3:
4:
Due east
Almost due east (within 5 degrees)
South of east (by more than 5 degrees)
North of east (by more than 5 degrees)
Charles Hakes
Fort Lewis College
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On December 21, in Australia, if there is a full
moon, where does it rise?
1:
2:
3:
4:
Due east
Almost due east (within 5 degrees)
South of east (by more than 5 degrees)
North of east (by more than 5 degrees)
Charles Hakes
Fort Lewis College
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On December 21, in Australia, if there is a full
moon, where does it rise?
1:
2:
3:
4:
Due east
Almost due east (within 5 degrees)
South of east (by more than 5 degrees)
North of east (by more than 5 degrees)
Charles Hakes
Fort Lewis College
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A 5 meter (diameter) telescope
1 : gathers 5 times as much light as a 1 m telescope
2 : gathers 1/2 as much light as a 10 m telescope
3 : gathers 4 times as much light as a 2.5 m telescope
4 : gathers 5/2 as much light as a 2 m telescope
Charles Hakes
Fort Lewis College
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A 5 meter (diameter) telescope
1 : gathers 5 times as much light as a 1 m telescope
2 : gathers 1/2 as much light as a 10 m telescope
3 : gathers 4 times as much light as a 2.5 m telescope
4 : gathers 5/2 as much light as a 2 m telescope
Charles Hakes
Fort Lewis College
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Which statement about planetary
orbits is incorrect?
A) All planets orbit the Sun counterclockwise.
B) Most stay close to the earth's equator in the sky.
C) Most orbits are almost circular, with low eccentricities.
D) All have the Sun at one focus of their elliptical orbits.
E) Most also rotate counterclockwise on their axes as well.
Charles Hakes
Fort Lewis College
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Which statement about planetary
orbits is incorrect?
A) All planets orbit the Sun counterclockwise.
B) Most stay close to the earth's equator in the sky.
C) Most orbits are almost circular, with low eccentricities.
D) All have the Sun at one focus of their elliptical orbits.
E) Most also rotate counterclockwise on their axes as well.
Charles Hakes
Fort Lewis College
47
Iron meteorites are believed to come
from:
A) the core of a differentiated asteroid, now broken up.
B) the crust of a differentiated asteroid, now broken up.
C) a broken up cometary nucleus.
D) debris from the Kuiper Belt.
E) interstellar space.
Charles Hakes
Fort Lewis College
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Iron meteorites are believed to come
from:
A) the core of a differentiated asteroid, now broken up.
B) the crust of a differentiated asteroid, now broken up.
C) a broken up cometary nucleus.
D) debris from the Kuiper Belt.
E) interstellar space.
Charles Hakes
Fort Lewis College
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Long-period comets are believed to
originally come from:
A) the asteroid belt.
B) the Kuiper belt.
C) the Oort cloud.
D) the satellite system of Jupiter.
E) the interstellar medium.
Charles Hakes
Fort Lewis College
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Long-period comets are believed to
originally come from:
A) the asteroid belt.
B) the Kuiper belt.
C) the Oort cloud.
D) the satellite system of Jupiter.
E) the interstellar medium.
Charles Hakes
Fort Lewis College
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The impact of a fragile body in June 1908
produced a huge explosion over:
A) northern Canada.
B) Alaska.
C) Siberia.
D) Mars.
E) the Moon.
Charles Hakes
Fort Lewis College
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The impact of a fragile body in June 1908
produced a huge explosion over:
A) northern Canada.
B) Alaska.
C) Siberia.
D) Mars.
E) the Moon.
Charles Hakes
Fort Lewis College
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In what part of the atmosphere does life
occur?
A) exosphere
B) stratosphere
C) mesosphere
D) ionosphere
E) troposphere
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Fort Lewis College
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In what part of the atmosphere does life
occur?
A) exosphere
B) stratosphere
C) mesosphere
D) ionosphere
E) troposphere
Charles Hakes
Fort Lewis College
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Which planet shows the widest range of surface
temperatures between day and night?
A) Mercury
B) Venus
C) Earth
D) Mars
E) Uranus
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Fort Lewis College
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Which planet shows the widest range of surface
temperatures between day and night?
A) Mercury
B) Venus
C) Earth
D) Mars
E) Uranus
Charles Hakes
Fort Lewis College
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Which body has the densest atmosphere?
A) Mercury
B) Venus
C) Earth
D) Mars
E) our Moon
Charles Hakes
Fort Lewis College
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Which body has the densest atmosphere?
A) Mercury
B) Venus
C) Earth
D) Mars
E) our Moon
Charles Hakes
Fort Lewis College
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Which of these gets brightest; so bright as
to be seen during daylight at times?
A) Mercury
B) Venus
C) Mars
D) Jupiter
E) Saturn
Charles Hakes
Fort Lewis College
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Which of these gets brightest; so bright as
to be seen during daylight at times?
A) Mercury
B) Venus
C) Mars
D) Jupiter
E) Saturn
Charles Hakes
Fort Lewis College
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Assume a planet orbits exactly three
times as far from the Sun as the Earth.
1 - It’s period is 3 years exactly.
2 - It’s period is between 3 and 5 years
3 - It’s period is between 5 and 7 years
4 - It’s period is 7 years or more.
Charles Hakes
Fort Lewis College
62
Assume a planet orbits exactly three
times as far from the Sun as the Earth.
1 - It’s period is 3 years exactly.
2 - It’s period is between 3 and 5 years
3 - It’s period is between 5 and 7 years
4 - It’s period is 7 years or more.
Charles Hakes
Fort Lewis College
63
Two planets have orbits with the same
sized semi-major axis. Which is true?
1 - The planet with the most eccentric orbit moves
faster all the time.
2 - The planet with the most eccentric orbit moves
faster some of the time.
3 - The planet with the most eccentric orbit never
moves faster.
4 - Not enough information to answer.
Charles Hakes
Fort Lewis College
64
Two planets have orbits with the same
sized semi-major axis. Which is true?
1 - The planet with the most eccentric orbit moves
faster all the time.
2 - The planet with the most eccentric orbit moves
faster some of the time.
3 - The planet with the most eccentric orbit never
moves faster.
4 - Not enough information to answer.
Charles Hakes
Fort Lewis College
65
A fast moving freight train hits a car. The
car is destroyed and the train isn’t, so…
1 - the magnitude of the force of the train on the car is greater
than the magnitude of the force of the car on the train
2 - the magnitude of the force of the train on the car is smaller
than the magnitude of the force of the car on the train
3 - the magnitude of the force of the train on the car is equal to
the magnitude of the force of the car on the train
4 - none of the preceding
Charles Hakes
Fort Lewis College
66
A fast moving freight train hits a car. The
car is destroyed and the train isn’t, so…
1 - the magnitude of the force of the train on the car is greater
than the magnitude of the force of the car on the train
2 - the magnitude of the force of the train on the car is smaller
than the magnitude of the force of the car on the train
3 - the magnitude of the force of the train on the car is equal to
the magnitude of the force of the car on the train
4 - none of the preceding
Charles Hakes
Fort Lewis College
67
Which has the most kinetic energy?
1: A 1 kg Mass with velocity 4 m/s.
2: A 2 kg Mass with velocity 3 m/s.
3: A 3 kg Mass with velocity 2 m/s.
4: A 4 kg Mass with velocity 1 m/s.
Charles Hakes
Fort Lewis College
68
Which has the most kinetic energy?
1: A 1 kg Mass with velocity 4 m/s.
2: A 2 kg Mass with velocity 3 m/s.
3: A 3 kg Mass with velocity 2 m/s.
4: A 4 kg Mass with velocity 1 m/s.
Charles Hakes
Fort Lewis College
69
Which mass pair has the greatest
gravitational force between them?
1: A 5Msolar mass and a 4Msolar mass separated by 4 AU.
1: A 4Msolar mass and a 3Msolar mass separated by 3 AU.
1: A 3Msolar mass and a 2Msolar mass separated by 2 AU.
1: A 2Msolar mass and a 1Msolar mass separated by 1 AU.
Charles Hakes
Fort Lewis College
70
Which mass pair has the greatest
gravitational force between them?
1: A 5Msolar mass and a 4Msolar mass separated by 4 AU.
1: A 4Msolar mass and a 3Msolar mass separated by 3 AU.
1: A 3Msolar mass and a 2Msolar mass separated by 2 AU.
1: A 2Msolar mass and a 1Msolar mass separated by 1 AU.
Charles Hakes
Fort Lewis College
71
Two planets have orbits with the same
periods. Which is true?
1 - Their velocities must be the same.
2 - They must have the same eccentricity.
3 - They must have the same semi-major axis.
4 - They must collide with each other.
Charles Hakes
Fort Lewis College
72
Two planets have orbits with the same
periods. Which is true?
1 - Their velocities must be the same.
2 - They must have the same eccentricity.
3 - They must have the same semi-major axis.
4 - They must collide with each other.
Charles Hakes
Fort Lewis College
73
Temperature
Which feels hotter?
1: 300° F
2: 300° C

Charles Hakes
Fort Lewis College
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3: 300° K
Temperature
Which feels hotter?
1: 300° F
2: 300° C
(Fahrenheit)
(Celsius)

Charles Hakes
Fort Lewis College
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3: 300° K
(Kelvin)
Assume that the Sun rises at 6:00 A.M. What
time does the third quarter Moon rise?
1:
2:
3:
4:
9:00 A.M.
12:00 noon
9:00 P.M.
12:00 midnight
Charles Hakes
Fort Lewis College
76
Assume that the Sun rises at 6:00 A.M. What
time does the third quarter Moon rise?
1:
2:
3:
4:
9:00 A.M.
12:00 noon
9:00 P.M.
12:00 midnight
Charles Hakes
Fort Lewis College
77
You are in Paris, France (50 degrees north
latitude), on June 21.
What is the highest angle above the horizon that
the Sun achieves?
1: 16.5° above the Southern horizon
2: 26.5° above the Southern horizon
3: 63.5° above the Southern horizon
4: 73.5° above the Southern horizon

Charles Hakes
Fort Lewis College
78
You are in Paris, France (50 degrees north
latitude), on June 21.
What is the highest angle above the horizon that
the Sun achieves?
1: 16.5° above the Southern horizon
2: 26.5° above the Southern horizon
3: 63.5° above the Southern horizon
4: 73.5° above the Southern horizon

Charles Hakes
Fort Lewis College
79
Observing from a latitude of 25° North
1 - The star Polaris appears about 65° above the horizon.
2 - The celestial equator has a maximum height of 65° above
the horizon.
3 - The star Polaris appears about 25° north of the zenith
point.
4 - The celestial equator has a maximum height of 25° above
the horizon.
Charles Hakes
Fort Lewis College
80
Observing from a latitude of 25° North
1 - The star Polaris appears about 65° above the horizon.
2 - The celestial equator has a maximum height of 65° above
the horizon.
3 - The star Polaris appears about 25° north of the zenith
point.
4 - The celestial equator has a maximum height of 25° above
the horizon.
Charles Hakes
Fort Lewis College
81
The universe became transparent to
radiation during:
A)
B)
C)
D)
Nucleosynthesis
Decoupling
Structure Formation
Cosmic Acceleration
Charles Hakes
Fort Lewis College
82
According to standard Big Bang theory, if
Ho=50km/s/Mpc, the maximum universe age is:
A)
B)
C)
D)
12 billion years
14 billion years
17 billion years
20 billion years
Charles Hakes
Fort Lewis College
83