Transcript Mercury & the Moon

Mercury & the Moon
Mercury and the Moon:
What can we learn?

What do we know?

Why is it important?
Mercury and the Moon:
What can we learn?

What do we know?

Why is it important?
Mercury
Mercury
Mercury’s Impact History
Huge impact craters as well as thousands of
smaller ones…
Mercury’s Impact History
Very Similar features on our Moon
Moon
Mercury
Mercury’s plains
Very Similar features on our Moon
Mercury’s plains
History told by craters!
Tectonics on Mercury
Long cliffs indicate that Mercury shrank early in its
history.
Mercury’s core
Mercury’s core: A Hypothesis
Mercury’s core: A Hypothesis
Mercury’s core: A Hypothesis
News from Mercury
NASA’s Messenger Mission now
mapping Mercury’s Surface
http://www.nasa.gov/mission_pages/messenger/main/index.html
Latest Photos of Mercury
Latest Photos of Mercury
Ice!
ICE?$$%##
I thought
Mercury was
> 700 °F
degrees in the
sunlight??
Where the sun doesn’t shine…
A great example of the process
of science…
Radio
Telescope
Observations
in 1990’s
A great example of the process
of science…
Radar
reflects from
bright spots
But is it ice??
Latest Photos of Mercury
Why Explore Mercury?
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Learning about Earth from other planets…
Core
 Magnetic Field
 Role of Solar Energy Exposure
 Planetary Models
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NASA’s view
Our Moon
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Some volcanic activity 3 billion years ago must
have flooded lunar craters, creating lunar maria.
The Moon is now geologically dead.
The Origin of the Moon: An
Example of the Process of Science
Where did the
moon come
from?
 How do we
know?

How do we explain the
existence of our Moon?
•Terrestrial planets don’t have moons….
•Our Moon is VERY large compared to its “partner”
•Composition is both like Earth…
•Rocky materials, similar to Earth’s Crust
•…and NOT like Earth:
•No water, no atmosphere, not a large metal core
How do we explain the
existence of our Moon?
•FOUR (4) Theories
• Formed at the same time, alongside Earth
• Formed from Earth’s materials
• Captured as it passed by
• Result of Giant Impact
How do we explain the
existence of our Moon?
•Formed at the same time, alongside Earth
•The “Sister” Theory…
•But then
•Should have the same composition…
•Should have water & “volatiles”
•Should have similar density
•It doesn’t, so rule this one out…
How do we explain the
existence of our Moon?
•Formed from Earth’s materials
•As earth formed, it “spun out”
•“Fission Theory”
•But then…. again
•Should have water & “volatiles”
•Should have similar density
•It doesn’t, so rule this one out…
How do we explain the
existence of our Moon?
•Captured as it passed by
•“Capture Theory”
•But then….
•How can this be done?
•It is very unlikely, so rule this one out…
Captured Moons
•
The unusual moons of some planets
may be captured planetesimals.
How do we explain the
existence of our Moon?
•Result of Giant Impact
•Mars-sized impactor strikes Earth a glancing blow
• Impactor destroyed, creates a debris ring
•Gravity takes over….the Moon is born.
•Lacks “volatiles” and water & Iron
•Computer models show this to be possible!
Giant Impact
Giant impact stripped matter from Earth’s crust
Stripped matter began to orbit
Then accreted into Moon
Our Moon
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Should we go back?
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What can we still learn?
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NASA Laser Communication System Sets Record with
Data Transmissions to and from Moon (10/22/13)
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Lunar Reconnaisance Orbiter Views (2
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LCROSS Satellite wins Technology Award (2011)
LRO image of
Peak in Crater Tycho
LRO image of
Soviet Luna Lander
LRO image of
Moon’s North Pole
LCROSS
LCROSS find water
on the Moon
LCROSS find water
on the Moon