Transcript The Eastern Seas - Olympic Astronomical Society

The Moon’s Eastern Seas
• Part 1: Formation & Evolution of
the Moon
• Part 2: Lunar Libration
• Part 3: The Eastern Seas
Geologic timeline of Earth
4570 Earth Formation
1800 First Complex single-cell life
380 First Vertebrate Land Animals
230-65 Dinosaurs
80-55 Rocky Mts. Uplift
0.0117 Glaciers Retreat
Geologic timeline of Moon & Earth
4570 Earth Forms
4533 Moon Forms from Giant Impact
Formation & Evolution of the Moon
Nectarian
Imbrian
Marginis
Australe
Tranquillitatis
Nubium
Smythii
ORIENTALE
Fecunditatis
Lava
Flows
Grimaldi
Surface Late Heavy
Hardens Bombardment
Eratosthenian
Pythagoras, Theophilus,
Langrenus, Hercules
COPERNICUS
Insularum
ERATOSTHENES
Procellarum
NECTARIS
IMBRIUM
PreNectarian
Nectaris, Humboldtianum, Humorum,
Crisium, Serenitatis
Copernican
Tycho,
Aristarchus,
Kepler
N
O
W
COPERNICUS
Nectarian
ERATOSTHENES
PreNectarian
ORIENTALE
NECTARIS
IMBRIUM
Timeline for Lunar Lava Flows
Basalt Units
50
40
30
20
10
Lunar Volcanic Activity
N
O
W
Beginning
of the Late
Imbrian
Period
Drawing by
Don Davis
End of the
Late
Imbrian
Period
Drawing by
Don Davis
Present
Day Moon
Drawing by
Don Davis
Lunar Libration
Lunar Directions
N
W
E
S
The Eastern Seas
N
E
In early February the 6-day-old Moon was Librated so that
more of the eastern area was visible than usual.
Mare Humboldtianum
Mare Humboldtianum
Located in the Moon’s NE Corner
Outer Basin is 600 Km in Diameter
Formed during the Nectarian Period
Inner Basin & Mare are 300 Km in Diameter
The Basin formed during the Nectarian
Period, and filled with lava during the Late
Imbrian
Named for Alexander von Humboldt by
Johann H. Mädler
Late Heavy
Bombardment
Lunar Periods
Alexander von
Humboldt
•
(September 14, 1769 – May 6, 1859)
was a Prussian geographer, naturalist
and explorer. Humboldt's quantitative
work on botanical geography laid the
foundation for the field of
biogeography.
Johann
Heinrich
von Mädler
(May 29, 1794 – March 14, 1874)
one of the great and eminent
astronomers of the 19th century.
Has a crater on the Moon and one
on Mars named for him.
Mare Smythii,
Mare Smythii
• One of the lowest Maria, 4 – 4.5
Km below the avg. Lunar Surface
• Impact basin is Pre Nectarin, 350
- 400 Km in diameter
• Southern floor is late Imbrian
basalt. Northern floor is from
the Eratosthenian period & may
be only 1 – 2 billion years old.
Named for Admiral William Henry Smyth (21 Jan. 1788 – 8 Sep.1865),
English naval officer & astronomer. President Royal Astronomical
Society. Published Bedford Catalogue with observations of 1604 double
stars and nebulae (with a 5.9-inch refractor).
Mare Marginis
Mare Marginis (The Sea of the Edge)
• Thought to be one of the oldest
Maria on the Moon. About 200
Km north-to-south.
• Apparently not area with a major
impact basin. Appears to be a
low-lying area where lava filled
several cratered areas where the
lunar crust was relatively thin.
The lava flows are also thin,
being only an estimated 1000 to
1700 feet thick.
• The highland area is PreNectarian and lava flows are
probably Late - Imbrian
Mare Anguis, Undarum & Spumans
Mare Anguis
Mare Undarum
Mare Spumans
(Serpent Sea)
(Sea of Waves)
(Foaming Sea)
(150 Km long)
(240 Km dia.)
(140 Km dia.)
• All three Maria are of Nectarin origin, with lava filling them
during the Late Imbrian Period.
Mare Australe
(The Southern Sea)
• This 600 Km heavily-cratered basin was formed during the preNectarin period, and filled with lava during the late Imbrian period.
• The basin is located in the Southeast area of the moon, and half of the
basin is on the far side, but can be seen (barely) during favorable
librations.
References
• The Modern Moon – a personal view
– By Charles A. Wood
• The Geologic History of the Moon
(US Geological Survey Professional
Paper 1348) –By Don E. Wilhelms
• Wikipedia
• “Eastern Seas” photo taken with 6” f/8
Refractor at prime focus, Canon Rebel
DSLR, ISO 100, 1/250th second
• http://www.lpod.org/cwm/DataStuff/pro
nounce/Introduction.htm
The End!
Questions?