Lecture 5 Flashcards
Why is the moon so important
- it is the only other planet on which humans have set foot
- it provides a record of the first 1 billion years of the solar system history
- provides insights into the basic mechanics of planetary evolution
What is the period of rotation of the moon on its axis
-27.3 days
What is the period of revolution of the moon around the Earth
- it is 27.3 days
- >one side always faces the Earth
Does the moon stabilize the Earth’s tilt
-yes
Does the gravitational attraction between Earth and Moon cause slightly elliptical shape
- yes
- >results for tides on the Earth and the Moon
Does the Moon have a larger temperature variance than the Earth
- yes
- > because the Moon doesn’t have an atmosphere
- > so the Sun either falls directly on the Moon if it is facing it or it doesn’t if the Moon is not facing the Sun
- > differences between day and Night on the moon is drastic
What is Maria on the Moon
- it is plural of mare
- >they are relatively smooth, low, dark areas on the Moon
What is Terrae on the Moon
- plural of terra
- > densely cratered highland on the Moon
- > =anorthosite
- examples are Kepler and Copernicus on the near side
- rays from Tycho are large and can be traced across the vast surface of the Moon
Is there mare on the far side of the moon
- yes
- > but they are less extensive
- > most of it is filled with craters in the lighter color rocks
-there are differences in this side of the moon
What is the moon highest relief
- it is 16 km
- > it is as big as what we have on Earth
- > not because of plate tectonics or difference in crust types
- > but because of how these impact basins are preserved
-note there is no ocean level like on Earth for scientists to reference from
What is the Lunar time scale
- it was established in 1962 by Shoemaker and Hackman
- > using relative age determinations
- note at 4.5 billion years ago, the moon fomred
- > some 10 million years after the Earth formed
- > it was divided into different periods
-in the early period, lots of basins and craters were forming
Describe what was found at the edge of lmbria basins
- they are filled with maria(basalt)
- there is the formation of the lmbrium basin
- there is the formation of copernicus
- there is also the formation of eratos thenes(crater)
- out of the 4 things mentioned, the oldest is the formation of basin
- > you need the formation of basin before you fill it with mare basalt from lava coming up from the interior
- > the two craters, Copernicus and Eratos thenes sit on top of the basin and the basalt
Describe the craters Copernicus and Eratos thenes which form at the edge of lmbria basin
Copernicus
- > has visible ejecta everywhere but you can’t see much of the ejecta from Eratos thenes
- > as the ejecta from copernicus covers Eratos thenes
- > therefore, copernicus is younger than Eratos thenes
- note both these craters are youngers than the basin filled with basalt
- > because you cans ee how Eratos cuts into the rocks made of the basin edge
How is the process of lunar time scales developed
- a surface that has lots of impact craters is older
- > more time to accumulate craters
- > lunar time scales gives us insights into the entire bombardment history on the inner solar system
-the impact craters age are done from radiometric dating from the Apollo samples
Describe cratering on Moon over time
- there was a big drop off in cratering 3.9 billion years ago
- > this is due to continuing sweeping of planetisimals
- but there was also late heavy bombardment
- > a pulse of debris from the asteroid belt
