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The
Moon Intro
to Astronomy Archaeoastronomy |
The Moon Can You Answer the Following Questions? 1. Give an accounting of some of the vital characteristics of the moon. a. diameter ................................................................... _______________ b. average distance from earth ...................................... _______________ c. mass, as compared to earth's mass ............................ _______________ d. volume, as compared to earth's volume .................... _______________ e. density ..................................................................... _______________ f. period of revolution (sidereal) ................................... _______________ g. period of rotation ..................................................... _______________ h. period of phase change (synodic) .............................. _______________ i. lowest temperature/highest temperature ................... _______________ j. possesses an atmosphere (yes or no) ......................... _______________ k. possesses water (yes or no) ...................................... _______________ l. possesses gravity (yes or no) .................................... _______________
PHASES OF THE MOON
2. List the correct name for the lunar phase which would correspond to the four basic elongations of the moon which are given below. Also give the time of rise and set of the moon for each case. The elongation represents the angular separation of the sun from the moon in the sky. The phase period of the moon, also called the synodic period, represents the amount of time it takes the moon complete a day and night cycle. It equals 29-1/2 days.
MOON - quadrature Phase(s):________________ Rise:_______ Set:_______ elongation = 90°
MOON - opposition Phase:________________ Rise:_______ Set:_______ elongation = 180° N
MOON - conjunction Phase:________________ Rise:_______ Set:_______ elongation = 0°
3. The _______________ period equals the time it takes the moon to make one complete revolution around the earth. Its period equals _______________ days.
4. The _______________ period equals the time it takes for the moon to cycle through a complete a series of phases. One lunar phase period occurs every _______________ days.
5. The phase period of the moon is different from its revolutionary period because the earth _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________
6. Because the moon keeps its same face towards earth at all times, the moon makes one complete _______________ in the same period of time which it takes to orbit the earth. These two period are said to be _______________.
7. The "dark side" of the moon really indicates the hemisphere of the moon which cannot be _______________ from earth. A better term would be the _______________ side, since the dark side of the moon implies that this region of the moon does not receive any sunlight. The "dark side" of the moon is completely in the light of the sun at ____________________ (phase of moon as seen from earth).
8. On the lunar surface, the period between sunrise and the next sunrise would take _______________ days.
FORMATION OF THE MOON: Accretion, Collision-Accretion, Fission, Capture
9. The _______________ theory claims that the moon was once a part of the earth which broke away early in the history of our planet. The Pacific Ocean basin was once thought to be the region where this origin occurred. Its density and volume are consistent with the moon's density and volume. However, geologists now know that the Pacific Ocean basin could not have been the source of the moon's formation because of ____________________.
10. One problem with the above theory is that when a secondary body of the same density as its primary, approaches its primary to within 2.44 times the radius of the primary, the secondary body will ____________________. This region is called the _______________ limit. The time period in which the moon would have been within this limit would have been LONG/SHORT (circle one).
11. If the moon formed by the capture of smaller particles which were orbiting the earth, then the _______________ theory is the correct one.
12. If the moon was formed in some unknown distant location in the solar system, than the earth must have _______________ the moon. This unlikely since the motion of the moon would have had to have been counterclockwise after the capture occurred.
13. A variant of all three theories is that early in earth's history a large planet-sized object _______________ with our world catapulting large quantities of debris into earth orbit which _______________ (came together) to form the moon. One theory suggests that the object which struck our world was the planet _______________.
14. The moon probably formed through the _______________ of debris in earth orbit, early in the history of the solar system or through the _______________ of another large object with the earth which threw debris into orbit which _______________ to form our natural satellite called the moon. Regardless of which hypothesis is correct, accretion played a central role in the formation of our moon.
CHRONOLOGY OF MAJOR LUNAR EVENTS
15. A casual inspection of the full moon with the unaided eye reveals light and dark regions referred to as _______________ and _______________ respectively. These reveal a major epoch in the geologic history of the moon.
16. In the beginning probably all of the moon was molten after it accreted. The moon began to cool, and the rock crystals which formed either moved towards the surface or sank, depending upon the _______________ of the material. This process of separation is known as ____________________.
17. As the planets and their satellites swept up the remaining solar system debris, cratering dwindled and the entire surface of the moon looked basically like the _______________ do today. Some major catastrophic event in the solar system, possibly the formation of the _______________ belt, occurred early in its history releasing a large number of bodies which impacted on the planets and on the young moon's surface. This occurred about _______________ billion years ago.
18. These major impacts on the moon began the formation of the lunar _______________ which are hundreds of miles in diameter. After their creation, several hundred million years elapsed during which nothing much happened. Then _______________ from warmer, denser regions underneath the crust gradually began to seep from the fractures surrounding these huge craters. Now, for a period of several hundred million years these depressions were actively being filled with _______________. The igneous material which covered the basins, layer upon layer, was denser, because chemically it contained larger quantities of _______________. These darker regions today are known as the _______________.
19. For the past ONE/TWO/THREE (circle one) billion years, since the inundation of the basins with lava, the moon has for all geological purposes been a dead world.
20. This can be confirmed from earth, because the _______________ are relatively crater free, indicating that since their formation, billions of years ago,__________________________ ________________________________________________________________________ (Hint: See the next question below if you are having difficulty the above question.)
21. The number of craters which a region contains is an indication of its relative _______________ in comparison to other locations surrounding an area which may have more or less impacts. Fewer craters indicates that the area is _______________ in comparison to another location which may have more craters.
APPEARANCE AND GEOLOGY OF THE MOON
22. The moon as viewed with the unaided eye appears to have dark areas. These darker regions are called _______________ after the Latin word for _______________. Circle the correct words which apply to the darker regions of the moon. older, newer, flatter, rougher, denser, less dense
23. The regions of the moon's surface which appear brighter are termed the lunar ____________. The words not circled in the last statement apply to these regions of the lunar surface.
24. _______________ is another word for the reflectivity of an astronomical body. The reflectivity of the moon's surface is HIGH/LOW (circle one). The various shades of gray on the moon are similar to a ________________________________________________.
25. The moon appears bright in the nighttime sky because the sky is so _______________ in contrast.
26. All of the rocks on the moon are mainly composed of varying combinations of the elements _______________ and _______________. Smaller amounts of other atoms and compounds create the characteristics which allow one to differentiate whether these rocks belong to maria or highland varieties.
27. The highland rocks, which originally composed the entire surface of the moon have more _______________ and _______________. These are less massive atoms than those which are contained in the denser lowland rocks which have more _______________ and _______________ within them.
28. The earth and moon probably received an equal pounding from meteorites throughout their respective histories. Yet the earth appears almost totally free of these blemishes while the moon does not. State three processes which have caused the earth to evolve more rapidly than the moon. a. ______________________________________________________________________ b. ______________________________________________________________________ c. ______________________________________________________________________
29. The surface of the moon evolved very slowly; yet it still changed over eons of time (billions of years). State three mechanisms which would be actively modifying the lunar surface at present. a. ______________________________________________________________________ b. ______________________________________________________________________ c. ______________________________________________________________________
30. As the moon ages, the albedo of the lunar soil becomes HIGHER/LOWER (circle one) as it sweeps up dust in its orbit around the earth. This is also common with other satellites in the solar system and is an indicator of younger versus older terrain.
31. When a large meteorite crater is formed, clumps of debris fan out and churn up the soil, exposing fresher material in elongated streaks called _______________. Any crater possessing these elongated streaks indicates that this feature is NEWER/OLDER (circle one) than the craters which are around it and devoid of this feature.
32. The far side of the moon possesses a thicker _______________ which may be attributable to debris thrown over into this area from the major impacts which formed the _______________ on the near side.
33. The major lunar features visible to earth observers without a telescope, but absent on the far side of the moon are the _______________.
34. Since the bulk density of the moon is similar to the moon's surface density, as well as the surface density of the earth, it seems reasonable to suspect that the moon does not possess any significant _______________.
35. Magnetic fields are usually associated with bodies that are rotating rapidly and possess a liquid core of iron or some other conducting medium. The moon WOULD/WOULD NOT (circle one) be expected to possess a magnetic field.
36. It is thought that all of the rocks on the moon are IGNEOUS/SEDIMENTARY/ METAMORPHIC (circle one).
37. The lithosphere of a body represents that part of an object which is in the _______________ phase (physical state). A layer called the asth_______________ usually occurs below the lithosphere when temperatures are high enough to allow the material to flow or deform. This region is not considered to be liquid, however. On earth, the continents float and move around on this portion of the upper mantle.
38. The moon's lithosphere is THIN/DEEP/VERY DEEP (circle one). Because of this, active volcanism WOULD/WOULD NOT (circle one) be expected to be occurring on the lunar surface at present.
39. Prior to the human conquest of the moon, an ingenious series of vehicles were sent to the moon to learn more about its properties. ________________ spacecraft hard-landed during the early to mid-60's. Later, soft-landing _______________ spacecraft investigated the lunar environment at specific locations, while ____________________ circled the moon to photograph its surface for prospective landing sites.
40. It was absolutely necessary to send satellite orbiters and landers to the moon prior to the Apollo missions. Telescopes on earth could not record lunar detail clearly enough because of _______________ turbulence. Remember the series of slides, taken from earth and from lunar orbit, which detailed the crater Copernicus.
CRATERING
41. When a large meteorite strikes the surface of a planet or a satellite, the target area reacts much like a SOLID/LIQUID/GAS (circle one). During the deceleration of the meteorite, a tremendous amount of heat is released which causes most of the impacting body to be _________________.
42. A large meteorite produces a crater in which the walls of the crater are HIGHER/LOWER (circle one) than the surrounding terrain, and the floor of the crater is HIGHER/LOWER (circle one) than the land around it. This is one way of distinguishing an impact crater from one formed through the process of _________________.
43. In a traditional volcanic mountain, the crater walls are HIGHER/LOWER (circle one) than the surrounding terrain, while the crater floor is HIGHER/LOWER (circle one) than the land around it. In a volcanic pit crater, the crater walls are LOWER/EVEN/HIGHER (circle one) than/with the surrounding while the pit is LOWER/EVEN/HIGHER (circle one) than/with the land around it.
44. Many larger lunar impact craters display a mountain in the middle of the formation, known as a ___________________. These features may be the result of the slumping (collapse) of the crater walls, the rebound or splash effect which may occur after impact, or simply _________________ caused as an aftermath of impact due to the tremendous amounts of heat which are generated during the crater formation process.
45. Fractures (faults or weak zones) along the walls of a crater often cause the walls to collapse in a step like configuration which is known as _______________.
46. Many larger meteorite craters display smooth floors which may be the result of v_______________ which occurred after impact or the melting of surface rocks from the heat released during impact.
47. Smaller impact features which surround a larger crater are often the result of objects which have been thrown from the crater during its formation. These are called _______________ craters.
48. Any feature which overlaps, intrudes, or is contained within another formation can be said to be YOUNGER/OLDER (circle one) than the other structure.
49. Younger craters appear to have _________________ boundaries while older craters have become more _________________ during eons of bombardment and lunar weathering.
50. ________________ rilles probably acted like lunar rivers during the time period after the great bombardment of asteroidal sized meteorites. However, one apparent difference was that these rilles carried ________________ rather than water. These features may reveal themselves as a series of ________________ chains if the rille was underground and sections of the tube have collapsed.
51. ________________ rilles are graben faults which may have been caused by upward magmatic movement and doming, or the shrinking and cracking of large expanses of lava during cooling. In the former case they represent a mechanism by which crustal tensions are released through the creation of more surface area.
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