Surface of the Moon
Abstract
By studying in detail the various surface features of the Moon, we are able to infer the age of the surface in different areas, speculate on how features came to be on the Moon, and piece together the chronological order in which these features were created. Over the course of several missions to the Moon, we have been able to collect samples and study the composition of the Moon's surface, paying particular attention to the dark, smooth, maria which shows that the Moon once had volcanic activity.
Introduction
In this lab, students studied various surface features of the Moon, including maria, mountains, and craters, and considered what the locations, shapes, and details of these features might imply about their ages and how they were formed. Using the knowledge gained from studying the Moon's features, students then compare the surface of the Moon with an image of Mercury. Additionally, students locate the landing sites of passed Apollo and Soviet Union missions to the Moon, noting their locations and why they landed where they did.
Procedure
Materials: Google Moon, Sky & Telescope's Moon Map, Lunar Reconnaissance Orbiter maps, several other Moon maps and globes provided in class and online
A: Students used available maps of the Moon to study the surface features, noting the location of craters, mountains, and maria. After familiarizing themselves with the maps and features of the Moon, students answered a set of questions provided with the lab.
B: Students used maps to locate and study two areas of the Moon, Mare Imbrium and Oceanus Procellarum. Within these two areas of maria, students were then directed to locate specific craters and, from the appearance of these craters infer whether the craters or maria were present first. The craters studied were Plato, Archimedes, Wallace, and Cassini in Mare Imbrium, Flamsteed, Letroone, Marius, Prinz and Herodotus in Oceanus Procellarum, and Kepler and Copernicus in Mare Insularum.
C: Students used images of the Moon's surface to compare and contrast large and small craters in the lunar highlands, also noting the patterns of overlapping craters and the presence or absence of central peaks within the craters.
D: Using Moon maps, students studied the shape and locations of mountain ranges on the Moon. As directed, students focused on the Apennine, Haemus Caucasus, Carpathian, and Pyrenes ranges, using them to answer questions provided with the lab.\
E. Students used Google Moon and the Lunar Reconnaissance Orbiter maps to study the far side of the Moon and compared and contrasted it's features with that of the side we can see.
F: After familiarizing oneself with the features of the Moon, students were presented with an image of Mercury and asked to note major differences and similarities between the surfaces, as well as explanations for these differences or similarities.
G: Given the coordinates of six Apollo missions, students located the landing site of each mission, noting the appearance, what the astronauts were interested in, and why they might have landed there.
H: Given the coordinates of three landing sites of unmanned missions to the Moon funded by the Soviet Union, students locate these sites on a Moon map. Similar to part G, students note the appearance and give and explanation for why the Soviet Union chose these areas to land on.
Results and Discussion
A:
1. Which of these features (maria, mountains, craters) are found mainly in the lunar lowlands and which are found mainly in the lunar highlands?
Maria is found mostly in the lowlands, and mountains are found mostly in the highlands. Craters are present in both areas, although many more are visible in the highlands than the lowlands, This is due to the fact that maria was once liquid and covered the lowlands of the moon, probably covering many craters in the process.
2. Which of these features frequently act as borders between the lowlands and highlands?
Maria often acts as a border between the lowlands and highlands. This makes sense, considering how liquid maria once spread through the lower regions of the surface, stopping when met with the higher elevation of the highlands.
3. As reckoned on the moon, in which quadrant of the side facing us are the maria mostly found?
The Northwest quadrant of the side facing us contains the most maria.
B:
1. If you restrict your view to the craters Plato, Archimedes, Wallace, and Cassini in Mare Imbrium and the craters Flamsteed, Letroone, Marius, Prinz, and Herodotus in Oceanus Procellarum, which would you say came first, the craters or the mare? Explain.
I would say that the craters were present before the mare. This makes sense because the craters appear to be partially filled in, with smooth, flat bottoms. This would not be present had the crater not been filled with liquid maria after its formation. This feature in noticable in the following image:
2. Now look at the craters Kepler and Copernicus in Mare Insularum, and explain which came first, the craters or the mare.
Because these craters don't appear to be filled, and instead have a true crater-shape, they formed after the mare was present. These craters leave a basin-shaped hole with an uneven surface, and appear to be a blemish in the smooth maria. Below is an image of the crater Copernicus, exemplifying these features:
3. Which other maria and craters could be used as examples of the scenarios depicted in the previous two questions?
The craters Parry and Guericke located in Mare Nubium both appear to have formed before maria was present, resulting in them being filled in. The craters Bullialdus in Mare Nubium and Manilius in Mare Vaporum both appear to have formed after maria was present on the moon, giving them the appearance of "cutting into" the maria.
4. Comment on the history of lava flows that produced the maria relative to when crater production occurred.
Lava flows on the moon occurred after the vast majority of crater production. This is evident in the distribution of craters and maria, as the majority of craters are visible in the lunar highlands, where lava did not cover the surface. Therefore, lava flows covered the majority of craters present in the lowlands, either swallowing it completely or giving the crater the appearance of being filled in. While some craters formed in the lowlands after maria was present, these are relatively rare and give us an idea of how violent our early solar system was.
C:
1. Do most large craters have central peaks? So most small ones?
On the moon's surface, most central peaks occur in medium- to large-sized craters, while most small craters do not possess central peaks. Most large craters do have central peaks unless there are overlapping craters that would destroy such features.
2. When overlapping occurs, do the larger or smaller craters appear to be younger? Why?
The smaller craters appear to be younger because they are overlaid on top of the large craters, In other words, the normal shape of the larger crater is often blemished with the shape of a smaller crater. If the larger craters formed after the small craters, they would most likely demolish or disfigure the shape of the small crater due to the force of the impact.
3. Based on the evidence seen on the maps, what do you suspect the origin of lunar craters to be? Explain.
Based on evidence, the origin of lunar craters is the violent nature of our solar system as it was forming. The craters on the moon are from collisions with various objects and debris in our solar system. In the aftermath of the solar system's formation, large asteroids and other objects zoomed around at the mercy of the Sun's gravity and that of other large bodies. This resulted in many collisions at first, giving the lunar highlands their pocked appearance, but the rate of collisions slowed down with time. This decrease in collisions is evident in the relative smoothness of the maria in the lunar lowlands.
D:
1. What is the highest mountain of mountain range on the Moon? What is the approximate elevation?
The highest mountain is Mons Huygens. Its elevation is 4.3 kilometers.
2. In general, do the mountain ranges extend in straight or curved lines? Based on the evidence, what do you suspect the origin of lunar mountain ranges to be? Explain.
The mountain ranges extend in curved lines. Based on the maps, these mountain ranges appear to be the product of huge collisions between the Moon and other large bodies. When viewed at a distance, one can note how the mountain ranges look like parts of the rims of colossal craters that were filled in, altered, or resurfaced over time. This crater shape is evident in the following image of Mare Imbrium:
E:
1. What seems to be the major differences between the hidden and visible sides of the Moon?
The far side of the Moon possess a significantly larger amount of craters than the visible side, with very little maria or lunar lowlands. In fact, the surface of the far side is almost entirely covered in craters. The visible side, by contrast, contains a large amount of maria, with the most heavily cratered area being the southern/southwestern portion.
2. What are the main similarities?
The composition of the highlands on both sides appears to be the same, Additionally, when craters are present they are often overlapping, and both sides appear to have some craters filled with maria.
3. What would you say is the most prominent feature on the far side of the Moon? What kind of feature is it? Speculate on how it may have formed.
\ I would say that Mare Moscoviense, or the "Sea of Moscow" is the most prominent feature because it is one of the very few crater basins on the far side of the Moon to be deep enough to be filled with maria. Being one of the areas with a significant amount of maria on the far side, Mare Moscoviense is prominent because it smoothness and dark color stand out among the rest of the light, cratered surface. This feature formed as the result of a collision creating a deep enough crater for lava flows to come to the surface. The following are images of the far side of the moon, where Mare Moscoviense is visible as a dark spot in the Northwestern quadrant, and of the maria itself:
4. Do the numbers of large and small craters appear to be the same on both sides of the Moon? If not, what differences do you note?
Because of the large amount of maria on the visible side of the Moon, the hidden side possesses many more craters of all sizes than the visible side. Proportionally, however, the visible side contains more small- to medium- sized craters, while the far side has more medium- and large- sized craters.
5. Do the shape and detail of craters on each side appear to be the same? Explain.
Other than the craters on the visible side that are partially filled with maria, the shape and properties of craters on both sides of the moon appear to be the same. Most craters are near circular, craters often overlap each other, and large craters possess central peaks, while small ones do not.
F:
1. What similarities do you find between the surface of the Moon and Mercury?
The Moon and Mercury possess both cratered areas and areas that appear smoother.
2. What major differences do you note?
Several craters on Mercury have visible stress cracks in the ground around and extending from the crater. No areas on Mercury are as heavily cratered as areas on the moon. Mercury has more diversity in the color of the surface.
3. Suggest reasons for any differences or similarities.
Both bodies possess craters and smooth areas because both were involved in collisions and had lava flow at some time. Mercury's surface is less cratered than the moon because its surface is younger, meaning that Mercury's lava flow occurred more recently than the Moon's. The cracks near Mercury's craters indicate that the craters formed after the smooth surface beneath them. The force of impact caused these features in the ground. The different colors present in the image of Mercury are evident of a diverse composition.
G:
Briefly comment on the following question for each Apollo landing site:
What is the general appearance of each landing site, which lunar features did the astronauts learn most about, and what reasons can you see for picking each particular spot?
Apollo 11: Landed in the mare, near the border between highlands and lowlands. Learned most about maria because it tells us about inner composition of the Moon.
Apollo 12: Landed in the mare, somewhat near highlands. Astronauts learned about mare and chose this spot because of its accessibility to mare.
Apollo 14: Landed in the maria, very near to landing site for Apollo 12. Again, astronauts learned most about maria and other moon rocks. The site was chosen probably for its location on maria and for it proximity to the landing site for Apollo 12.
Apollo 15: Very near the Appenine mountain range, bordering Mare Imbrium. Learned about maria and nature/formation of the mountain range. This site was probably chosen for its location close to maria and a mountain range.
Apollo 16: Landed in the highlands amidst many craters. Scientists were looking to learn about the composition of the highlands and the formation and properties of craters. This landing site was chosen for its flatness among the highlands, giving a nicer place to land, and for its location in the highlands and among craters.
Apollo 17: Among craters, on border between highlands and lowlands. Astronauts were once again looking to learn about the Moon's maria and draw conclusions about the Moon's structure and history. This landing site is strategic because it is near both maria and craters, allowing scientists to learn about both.
H:
Briefly comment on the following question for each Luna landing site:
What is the general appearance of each landing site, which lunar features were studied, and what reason can you see for picking each spot?
Luna 16: Landed in smooth maria, with some younger craters nearby. The maria was studied, and this site was chosen because of the presence of maria and the lack of other missions near there.
Luna 17: Border between highlands and lowlands, near the Jura mountain range. Scientists probably studied the mountains, the maria, and any craters nearby. This landing site was chosen because of its proximity to all three features.
Luna 21: Landed in the maria, near the border and a large, filled crater. Maria and craters were studied on this mission. The site was chosen for the presence of maria.
Conclusion
As evident in this lab, one can learn much and draw many conclusions just by studying the surface features of the Moon. For example, one may speculate on the age of certain features, note the similarities and differences between different areas of the Moon or between the Moon and other bodies in our solar system, and use the properties of surface features to infer how they were formed. Such observations and conclusions have led us to our thorough understanding of the Moon, its structure, and its history. Indeed, by first studying the Moon, man opened a door of observation and reasoning that has allowed us to find answers to these questions concerning more distant bodies in our solar system, giving us a more complete picture of the history and composition of our little island in the universe.
No comments:
Post a Comment