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Quiz:
Wednesday, November 9th
emphasis on Chapter 19
1
Tuesday, November 8, 2011
How do asteroids and comets differ?
1.
2.
3.
4.
5.
Asteroids orbit in the
opposite direction than
the sun rotates.
Comets are younger
than asteroids.
Asteroids have lower
reflectivity.
Comets contain ices.
all of these choices
Tuesday, November 8, 2011
Where are most asteroids located?
1.
2.
3.
4.
5.
inside the orbit of
Mercury
between the orbits of
Earth and Venus
between the orbits of
Earth and Mars
between the orbits of
Mars and Jupiter
between the orbits of
Jupiter and Neptune
Tuesday, November 8, 2011
Which properties of the solar
system are accounted for in
this simple series of three
diagrams depicting the solar
nebula hypothesis?
1.
2.
3.
4.
5.
the common direction of
revolution and rotation of
most solar system bodies
the planets orbiting the sun in
nearly the same plane
the common age of the sun
and the oldest meteorite
minerals
the common direction of
revolution and rotation of
most solar system bodies;
and the planets orbiting the
sun in nearly the same plane
all of these choices
Tuesday, November 8, 2011
How does the solar nebula theory account for the drastic
differences between terrestrial and Jovian planets?
1.
The temperature of the
accretion disk was high close to
the sun and low far from the
sun.
2.
Terrestrial planets formed closer
to the sun and are thus made of
high-density rocky materials.
3.
Jovian planets are large and
have high mass because they
formed where both rocky and
icy materials can condense.
4.
Jovian planets captured nebular
gas as they had stronger gravity
fields and are located where
gases move more slowly.
5.
all of these choices
Tuesday, November 8, 2011
Which of the following accurately describes the
differentiation process?
1.
High-density materials sink toward
the center and low-density
materials rise toward the surface
of a molten body.
2.
Low-density materials sink toward
the center and high-density
materials rise toward the surface
of a molten body.
3.
Only rocky materials can
condense close to the sun,
whereas both rocky and icy
materials can condense far from
the sun.
4.
Both rocky and icy materials can
condense close to the sun,
whereas only rocky materials can
condense far from the sun.
5.
Small bodies stick together to form
larger bodies.
Tuesday, November 8, 2011
Extrasolar Planets
Detection Techniques:
Doppler Method
Transit Photometry
Direct Imaging
Gravitational Lensing
Tuesday, November 8, 2011
The Doppler Method
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Tuesday, November 8, 2011
Measuring the Doppler Shift
9
Tuesday, November 8, 2011
Doppler Measurements
10
Tuesday, November 8, 2011
Doppler Method
Tuesday, November 8, 2011
Transit Photometry
12
Tuesday, November 8, 2011
Direct Detection of Extrasolar Planets
Only in exceptional
cases can extrasolar
planets be observed
directly.
Preferentially in the
infrared:
Planets may still
be warm and emit
infrared light;
stars tend to be
less bright in the
infrared than in
the optical
Tuesday, November 8, 2011
Chapter 21
The Moon and Mercury:
Comparing Airless Worlds
Tuesday, November 8, 2011
Outline
I. The Moon
A. The View From Earth
B. The Apollo Missions
C. Moon Rocks
D. The History of the Moon
E. The Origin of Earth's Moon
II. Mercury
A. Rotation and Revolution
B. The Surface of Mercury
C. The Plains of Mercury
D. The Interior of Mercury
E. A History of Mercury
Tuesday, November 8, 2011
Do all of the terrestrial planets have
a Moon?
Do any besides Earth?
16
Tuesday, November 8, 2011
Moons of Mars: Phobos & Deimos
17
Tuesday, November 8, 2011
Mars and its Satellites: Phobos and Deimos
Mass ratio (planet:satellite)=49,000,000:1
Size Ratio (planet:satellite)=300:1
The Earth and its Satellite: The Moon
Mass ratio (planet:satellite)=80:1
Size Ratio (planet:satellite)=3.7:1
Our Moon is very large!!
18
Tuesday, November 8, 2011
The Moon: The View from Earth
Front side that we see from Earth
Back side that we don’t
From Earth, we always see the same side of the moon.
The moon rotates around its axis in the same time that it
takes to orbit around Earth:
19
Tuesday, November 8, 2011
Tidal Coupling
Earth’s gravitation has
produced tidal bulges
on the Moon;
Tidal forces have slowed
the rotation down to the
same period as the
orbital period
20
Tuesday, November 8, 2011
Earthrise
Apollo 8 orbiter
December 24, 1968
21
Tuesday, November 8, 2011
Why does the same side of the
moon always face Earth?
1.
2.
The moon does not rotate.
The moon rotates in the
same direction that it
revolves.
3.
The moon's period of rotation
is equal to its orbital period.
Sometimes the back side of
the moon is lit by the sun.
The moon rotates in the
same direction that it
revolves; and the moon's
period of rotation is equal to
its orbital period.
4.
5.
Tuesday, November 8, 2011
How did the moon achieve its
synchronous rotation?
1.
When the moon formed, it just
happened to have this synchronous
rotation.
2.
The Earth raises tidal bulges on the
moon. As the moon rotated through
these bulges, internal friction slowed
the moon's rotation until it achieved
tidal coupling.
3.
Competing gravitational tugs on the
moon by the Earth and sun set up
this synchronous rotation.
4.
The moon pulls up a tidal bulge on
Earth, and Earth rotates so fast that
it has locked the moon into this
synchronous rotation.
5.
As the Earth and moon orbit their
common center of mass, the
centrifugal forces sent the moon
outward until this synchronous
rotation was achieved.
Tuesday, November 8, 2011
Lunar Surface Features
Two dramatically different
kinds of terrain:
• Highlands:
Mountainous terrain,
scarred by craters
• Lowlands: ~ 3 km lower
than highlands; smooth
surfaces:
Maria (pl. of mare):
Basins flooded by
lava flows
Tuesday, November 8, 2011
Copernicus: One of the youngest impact craters
25
Tuesday, November 8, 2011
Copernicus: One of the youngest impact craters
Mt. Diablo
SJSU
Novato
San Francisco
93 km
Tuesday, November 8, 2011
25
Highlands and Lowlands
Sinuous rilles =
remains of ancient
lava flows
May have been lava
tubes which later
collapsed due to
meteorite
bombardment.
Apollo 15
landing site
Tuesday, November 8, 2011
The Highlands
Saturated with craters
Older craters partially
obliterated by more
recent impacts
Tuesday, November 8, 2011
… or flooded by
lava flows
Impact Cratering
Impact craters on the moon
can be seen easily even
with small telescopes.
Ejecta from the impact can be
seen as bright rays originating
from young craters
Tuesday, November 8, 2011
History of Impact Cratering
Rate of impacts
due to
interplanetary
bombardment
decreased rapidly
within the first ½
billion years after
the formation of the
solar system.
The age of the
moon rocks
provide evidence
of a late heavy
bombardment
4.1 to 3.8 billion
years ago.
Tuesday, November 8, 2011
What do we know about the Moon?
Pre-1960’s: Not Much!
• Size & Mass  Average Density
Earth: 5.5 grams per cubic cm
Moon: 3.3 grams per cubic cm
• Distance to Moon  30 Earth diameters
• Rotation rate
• Orbital Period  about 27 days
• Obliquity (angle of its orbital plane)
• No atmosphere
• Geological activity? Probably not.
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Tuesday, November 8, 2011
What do we know? (cont)
Post-1960’s: Apollo Missions take us to the Moon
Seven manned missions between 1969 and 1972.
• Six successfully land
• Leave seismometers
• Leave reflectors
• Bring back 842 lbs of rock!
2,415 samples.
Study of Lunar Geology Begins!
31
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Need to carry enough
fuel for:
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Need to carry enough
fuel for:
• in-flight corrections,
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Need to carry enough
fuel for:
• in-flight corrections,
• descent to surface,
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Need to carry enough
fuel for:
• in-flight corrections,
• descent to surface,
•
re-launch from the
surface,
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Need to carry enough
fuel for:
• in-flight corrections,
• descent to surface,
•
re-launch from the
surface,
• return trip to Earth;
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Tuesday, November 8, 2011
Missions to the Moon
Major challenges:
Need to carry enough
fuel for:
• in-flight corrections,
• descent to surface,
•
re-launch from the
surface,
• return trip to Earth;
Need to carry enough
food and other life
support for ~ 1 week for
all astronauts on board.
Tuesday, November 8, 2011
Lunar module (LM) of
Apollo 12 on descent to
the surface of the moon
Missions to the Moon
Lunar module (LM) of
Apollo 12 on the surface
of the moon
Tuesday, November 8, 2011
Missions to the Moon
Solution:
Lunar module (LM) of
Apollo 12 on the surface
of the moon
Tuesday, November 8, 2011
Missions to the Moon
Solution:
• only land a small,
light lunar module;
Lunar module (LM) of
Apollo 12 on the surface
of the moon
Tuesday, November 8, 2011
Missions to the Moon
Solution:
• only land a small,
light lunar module;
• leave everything
behind that is no
longer needed.
Lunar module (LM) of
Apollo 12 on the surface
of the moon
Tuesday, November 8, 2011
The Apollo Missions
Tuesday, November 8, 2011