Section 9.3
Observations from the Earth:
1. Craters are the dominant features of the lunar surface.
2. The dark regions are called maria for seas and the lighter cratered regions are
called terrae land
3. The smaller dark regions of the Moon are called Lacus or lakes, Palus or marsh,
Sinus or bay.
4. The names were invented in the mid 1600s by Giovanni Riccioli.
5. Lunar mountains are named after mountains ranges on Earth.
6. Lunar 3 passed behind the moon and returned the first images of the side that
cannot be seen by Earth.
7. The US has announced plans for a series of man lunar missions beginning as
early as 2020.
8. By the time of the first robot lunar landers in 1966, there had been a number of
Soviet and American flybys which had crashed into the Moon
9. The layer of surface debris is called the regolith (blanket of rock)
10. The intrusion of dense mantle material into the fractured crust beneath the maria
produced concentrations of mass called mascons
11. Other lunar features that may have been caused by volcanic activity are rilles,
which may be either sinuous (winding) or straight
12. Sinuous rilles, such as Hadley Rille occur in the maria and resemble dry
riverbeds
Section 9.4
1. Lunar and terrestrial rocks are some of the most important clues to
understanding how the Moon is formed.
2. The Lunar samples returned by the 6 apollo missions and by 3 soviet sample
return missions have provided detailed info about the chemical makeup of the
surface layers of the moon.
3. Many Elements seem to be more abundant on the Moon than the earth but water
is almost completely absent.
4. The oldest lunar rocks are about 4.5 billion years old and are thought to have
solidified shortly after the formation of the moon.
5. Crater density is the number of craters of different sizes on a given amount of the
lunar surface area.
6. The terrae are virtually completely covered with craters 4km in diameter or larger.
7. The difference in crater density between the maria and the terrae tells us that the
terrae are older than the maria, but how much older cant be determined crater
density alone.
8. The ages obtained for lunar samples make it possible to know just how much
older terrae are than maria.
9. The cratering rate may have been even higher than 4 billion years ago, but little
of the earlier surface is left.
10. The general relationship between age and crater density hold for the surfaces of
the other planets and satellites as well as for the moon.
Section 9.5
1.
2.
3.
4.
The Moon has almost no atmosphere.
Total mass of the atmosphere is a few thousand kilograms
The Moon's atmosphere consists mainly of helium, neon, argon, and hydrogen
The thin atmosphere of the Moon poorly insulates the surface so the temperature
falls dramatically after sunset and rises swiftly.
5. One consequence of the Moon having nearly no atmosphere is that the sky is
always dark, even in the daytime.
6. From time to time, the Moon;s thin atmosphere is temporarily enhanced when
comets strike the lunar surface.
7. Upon impact, ice in the comet is vaporized and forms an atmosphere of water
molecules.
8. The existence of ice deposits at the north and south poles of the moon was
suggested by measurements made by the Lunar Prospector spacecraft.
9. The rocky soil of the Moon absorbs radio waves and is poorly reflecting.
10. Ice is highly reflecting at radio wavelengths.
Section 9.6
1. The mass of the Moon is approximately 7.4x10^22 kg.
2. the mass of the moon is 1/81 that of the earth.
3. The center’s mass of the earth and moon is only 4700 km from the center of the
earth.
4. The density of the moon is 3300 kg/m^3.
5. The moons metallic core makes up 13-20% of its diameter, and it makes up to 23% of it’s mass.
6. For seismometers were placed on the moon during the apollo missions and have
measures a two or below on the Richter scale.
7. The speeds from the seismometers imply that the crust of the moon is about 65150km thick.
8. The lithosphere is about 1000 km below the moon’s surface, and is where the
moon becomes partially molten.
9. The amount of magma and meteor impacts to one side of the moon has caused
the crust of the moon to be thicker on one side.
10. The apollo astronauts drove heat probes several meters into the lunar soil.
11. The moon’s heat flow is 1/3 that of the earth.
Section 9.7
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Until recently, there were only three theories of the moon, but all three of the
theories have flaws.
The Fission Theory
The Binary Accretion Theory
The Capture Theory
The fission theory said it would have flung up stuff from the equator
another problem is that The earth would not have been rotating fast enough to
have flung material off of itself
The binary accretion theory is also called the double planet theory
The binary accretion theory explains why the iron in the moon and earth are of
different composition.
The capture theory said that the moon formed somewhere else in the solar
system and that it was captured by the earth.
If the moon formed somewhere else it would not make sense that the moon and
earth are so similar in materials
Giant impact theory- proposes that the moon formed from debris expelled from
the earth when it was struck by a glancing blow by a body as massive as mars.