Mecury, Venus, Mars
Mercury, Venus and Mars
Can You Answer the Following Questions?
1. The average distance of Mercury from the sun is only _______________ miles, making it a difficult planet to observe from the earth because of its close proximity to the sun. A year on Mercury transpires in only ________________ earth days.
2. Prove to yourself that Mercury, just like the moon, goes through
a complete series of phases
3. The manner in which Mercury's brightness changes with its phase is in correlation with the moon's phase-brightness relationship. Astronomers assumed, even before the space-age, that there were similarities in the appearance between both bodies and thought that Mercury possessed a significant number of _________________.
4. The spacecraft which proved that Mercury did indeed look similar to the moon was called _______________ (1974).
5. On the earth, climatic variations are basically a factor of one's distance from the equator. This is climatic variation with respect to _______________.
6. Mercury's rotation and revolution are locked in a rigid dance, such that the location exposed to the noonday sun at perihelion will also be exposed to the noonday sun at perihelion exactly _______________ Mercury revolutions later. This is called spin-orbit coupling, and for Mercury it is in a ratio of 3:2. Therefore...
7. For every _______________ revolutions around the sun, Mercury makes exactly _______________ rotations on its axis.
9. Mercury, not only has the traditional climatic variations which occur with distance from the equator, like the earth, but Mercury also experiences climatic variations because of a location's _______________ position.
10. Mariner 10 photographed only half of the surface area of Mercury,
yet it made three flybys of the
planet before becoming nonoperational. Why was this the best NASA could
hope for with respect to the amount
of territory viewed by other Mariner-type spacecraft? Remember,
the satellite's period was 178 days, twice the period of revolution
11. The counterclockwise revolution of a body around the sun causes the sun and planets to move in a (an) _______________ direction among the stars.
12. The counterclockwise (west to east) rotation of a planet causes the stars and the sun to rise in the _______________ and set in the _______________ as witnessed by an individual viewing the sky from the surface of that body. This motion, as seen in the sky, is in a CLOCKWISE/COUNTERCLOCKWISE (circle one) direction.
13. At Mercury's hot spots (and everywhere on the planet) the sun rises in the ________________. As Mercury approaches perihelion and the sun approaches its noontime position, the sun's eastward motion due to the planet's revolution becomes greater than its westward motion caused by rotation. This makes the sun appear to stop its motion, then ____________________ for a period of seven days. After this interval the sun's apparent westward motion due to rotation once again exceeds the sun's apparent eastward motion due to revolution. The sun slowly heads for a set in the _________________.
14. The geological history of Mercury is similar to earth's moon.
Use the information presented below
to prescribe an evolutionary sequence for the moon and for Mercury.
Note the differences.
Moon: _______, _______, _______, _______, _______
15. Just like earth, Mercury's average density is presumed to be much
GREATER/LESSER (circle one) than
its surface density. This can only lead to the conclusion that Mercury
16. When a person looses weight too rapidly, the surface area of that individual INCREASES/DECREASES (circle one) faster than the elasticity of the skin can compensate. The result is an unwanted dermatological condition known as _______________.
17. It is assumed that the same situation occurred on Mercury. The planet cooled more rapidly because it was small. The core shrank, and the surface wrinkled to compensate for the decrease in surface area. Geologically these wrinkles on Mercury are called ____________________.
18. State one reason why Mercury should not possess a magnetic field,
even through it has been proven
that one does exist. ___________________________________________
19. One theory contends that the weak dipolar magnetic field surrounding Mercury resulted when portions of its nickel-iron core _______________ and assumed the magnetic field which was still being generated in deeper portions of the body. This type of "leftover" magnetic field is called _______________ magnetism. Currently there has been a return to more traditional concepts regarding the production of Mercury's magnetic field. Some geologists now believe that a portion of Mercury's core is still hot enough to be maintained in a liquid phase. Because of Mercury slow rotation the field strength would be very feeble.
20. Since the mass, volume, and density of Venus are so similar to
the _______________, one would surmise
that Venus should possess a partially melted core. Yet Venus does not
have a magnetic field in the traditional
sense. What characteristic, which is associated with planets that have
magnetic fields, is missing with Venus?
21. What little magnetic field Venus does possess is really more of a sunward generated atmospheric phenomenon. Plasma from the sun, known as the ____________________, ionizes the upper Venusian atmosphere creating a shock front and ionopause. This "field" causes the deflection of some of the ionized particles which approach it. If asked the question, "Does Venus possess a magnetic field?" you should respond with a YES/NO (circle one).
22. A train blowing its whistle approaches, then passes an observer.
Describe what is heard by the stationary
observer with respect to the pitch (highness or lowness) of the whistle.
23. The phenomenon, as described in the answer to the last question, is known as the ____________________ of sound.
24. As the train is approaching, the sound waves in front of it are being compressed. In other words the wavelengths of the sound are being SHORTENED/LENGTHENED (circle one), thus allowing more wave crests to be intercepted by the ear of the observer each second. The more wave crests passing an observer per second, the HIGHER/LOWER (circle one) the pitch. The number of wave crests passing an observer per unit time interval is known as the _______________.
25. As the train passes, the sound waves reaching the observer's ear are lengthened, fewer wave crests pass a given location per second. The pitch is _______________.
26. The Doppler shift works the same way with all of the different forms of radiation in the ____________________ spectrum. Remember that sound is a compressional wave and needs a medium through which it is transported. EM energy can also be propagated through a vacuum. In the case of Venus (and Mercury), ____________________ (a specific type of radiation) were transmitted from earth and reflected off the planet's surface. From one side of Venus the wavelengths of returning energy were slightly shorter than those originally transmitted, indicating movement of the planet TOWARDS/AWAY (circle one) the observer. From the other limb the reflected wavelengths of energy were slightly longer, indicating movement TOWARDS/AWAY (circle one) from the observer. This was conclusive enough proof to show that Venus (and Mercury) _______________.
27. Planets such as Venus, earth, and Mars probably had their primordial atmospheres stripped from them in the initial stages of the birth of the sun. These bodies would have obtained new atmospheres through the process of _______________.
28. Name some of the gases that would have accumulated in the atmosphere
of Venus, based upon your answer
to the last problem.
29. A particular gas on Venus called ___________________ is chiefly responsible for artificially elevating temperature on the planet. The temperature on Venus is approximately ____________________.
31. If the calcium carbonate (CaCO3) rocks of earth could be made to release their CO2 content, this planet's atmosphere, would contain about the _______________ quantity of CO2 as Venus. Remember, that earth's oceans would also boil, creating an additional 300 atmospheres over the 90-100 atmospheres released from the carbonate rocks. See below.
32. On earth the temperature is raised about 63° F (35° C) over what it would normally be without an atmosphere. This phenomenon is called the ____________________.
33. Greenhouse gasses such as CO2, H2O, CH4 (methane), and SO2 allow incoming visible _______________ radiation to reach the surface directly. This energy is absorbed and reemitted as _______________ radiation which these greenhouse gasses efficiently absorb, preventing the rapid escape of this radiation back into space.
34. The pressure exerted by the atmosphere of Venus is _______________ times greater than the pressure exerted by earth's atmosphere. This fact is also partially responsible for the high temperatures on the surface of this planet.
35. As a pocket of gas is heated, it begins to EXPAND/CONTRACT (circle one), thus causing a change in its density with respect to the gases which surround it. The pocket of gas now weighs MORE/LESS (circle one) than the "cooler" gases surrounding it, and the gas pocket begins to rise. This method of energy transport is called _________________.
36. On Venus, with its extremely massive atmosphere, the gases near
the surface of the planet must be
heated to very high temperatures before they can begin to push... (complete
the thought) _______________________________________________________________
37. Venus has multilayered cloud and haze zones which are predominantly composed of ____________________ droplets. Don't get the composition of the clouds confused with the atmospheric composition of Venus which is primarily _______________.
38. Liquid aerosol droplets condense in the upper levels of the Venusian atmosphere where conditions are cooler. They begin to fall towards the surface of the planet. As they descend, _______________ and pressures increase. Eventually at about the 30 mile level, _______________ wins out and the sulfuric acid vaporizes to begin journeying upward, where it will eventually condense once again to repeat this endless cycle.
39. Because the equatorial regions of Venus receive the greatest amount of energy, heat must be transferred from the ______________ to the _______________. However, unlike the more complicated patterns of earth, Jupiter, and Saturn, the Venusian atmosphere circulates in basically a ONE/TWO/THREE/FOUR (circle one) celled structure. The same Coriolis effect deflects the atmosphere of Venus.
40. The simpler circulation pattern of the Venusian atmosphere is a result of a very slow planetary _______________ rate.
41. The surface of Venus is a WINDY/CALM place. However, at the top of the Venusian atmosphere, the clouds are circulating around the planet in a period of only ____________________ days. They circle Venus in the DIRECTION/OPPOSITE DIRECTION (circle one) of the planet's rotation.
42. The Pioneer-Venus orbiter deduced that the surface of Venus had a varied topography. The satellite reflected microwaves from the planet's surface and noted the various time _______________ in the returned signal. Landforms which were higher, reflected the signal back to the spacecraft in a SHORTER/LONGER (circle one) duration of time than landforms which were lower.
43. The latest high tech spacecraft to be performing the same type of radar mapping, only in more detail, is named _______________.
44. In general terms, the surface topography (elevation of landforms)
on Venus is relatively FLAT/MOUNTAINOUS
(circle one). Keep in mind that the tallest mountain on Venus, Maxwell
Montes, a volcano, is about 7000 feet (2100 m) higher than Everest,
the tallest mountain on earth (30,000
feet or about 9000 meters).
46. Radar images of the surface of Venus appear bright and dark just like in a conventional black and white photograph. However, their interpretations are very different. Locations where the ground is rough appear BRIGHTER/DARKER on a radar image, whereas a smooth surface is a poorer reflector of energy and is portrayed as _______________.
47. On a radar image, lava flows emanating from a volcano would appear _______________ while the melted rock found inside of a large impact crater would look _______________.
48. One unique geologic feature found only on Venus are called Pancakes. They are volcanic domes, but very broad and flat. An explanation for their flatness has been attributed the crushing effects of Venus's _______________.
49. For all of the incredible amount of volcanic activity which is occurring or has occurred on Venus, it might be though that Venus's surface would be divided into a series of crustal plates similar to earth. On Venus, however, there does not appear to be any extensive convergent, divergent, or transform plate boundaries like the earth possesses. The process by which Venus releases its internal heat appears to be similar to very localized regions on the surface of the earth. One of these areas is the island group of Hawaii. The type of activity which is happening here is called ____________________ volcanism.
50. Considering the three major rock types, and what has been mentioned above, one would expect to find only _______________ rocks in great abundance on Venus's surface. _______________ rocks would be expected to be absent because Venus lacks any water. This is exactly what the Russian Venera landers discovered when they photographed the surface from close range.
51. Mars was once considered to be the abode of life because there
are so many similarities between
it and the earth. Name three of these basic similarities which could
be deduced from telescopic observations
of the planet. Mass, volume, density and composition will not be accepted.
52. The American astronomer, Percival _________________ founded an observatory in Flagstaff, Arizona, (near the Grand Canyon) to investigate the possibility of _________________ on Mars.
53. He believed that Mars possessed a dying civilization, which lived near the equator of the planet. These "creatures" were pumping water from the two Martian polar caps via a planet-wide network of _________________ which were faintly visible from earth.
54. Although V______________ landers continued the search for life on the planet Mars during the mid- 1970's, the conclusion reached by NASA scientists was that no life was present. The landers failed to detect any _______________ molecules in the soil which would have suggested that life existed on the Red Planet.
55. There were three life experiments which were performed on the
surface of Mars by each of the Viking
landers. One took Martian soil and fed it with all of the nutrients
which plant life could possibly
want. Sensors in the chamber were designed to monitor changes in the
gas content which would signify
that there was life in the soil. What kinds of changes were NASA scientists
looking for? ____________________________________________
56. The second life experiment moistened a sample of Martian soil
with nutrients tagged with radioactive
carbon 14. If the soil contained animal life, these life-forms would
metabolize the foodstuffs and release
waste gases back into the chamber. What were scientists looking for
in this experiment to show that
animal life existed on the planet Mars? ________________________________________________________________________
57. The third life experiment provided a soil sample with the equivalent
of Martian sunlight minus the _______________
radiation which would be striking the surface of the planet. Radioactive
carbon 14 gas was put into the chamber,
and it was hoped that if life did exist in the soil that some
of the C14 would be ingested by the living organisms. After a period
of time, the container was evacuated
and heated to a temperature where the organic molecules would have been
broken down and vaporized. How would
scientists have detected that life processes were occurring
after the sample was fried? ________________________________________________________________________
58. Make a statement concerning the significance of the Mars Viking
probes in light of the biology experiments.
59. Now in August of 1996 a NASA research team at the Johnson Space Center and at Stanford University have announced that there is evidence that strongly suggests primitive life may have existed on Mars more than 3.6 billion years ago. The NASA-funded team found the first organic molecules thought to be of Martian origin; several mineral features characteristic of biological activity; and possible microscopic fossils of primitive, bacteria-like organisms inside of an ancient Martian rock that fell to Earth as a _______________. The specimen was thought to have been lobbed off Mars about 15 million years ago. It will probably take several years for the scientific community to come to some type of consensus over this find. However, the initial evidence is intriguing.
60. Early Mariner flybys of Mars which favored the southern hemisphere revealed a planet which looked surprisingly like (the) ______________.
61. The true surface of Mars was revealed when Mariner 9 (1971) went into orbit around the planet and photographed two very earthlike features, _________________ and _________________.
62. After Mariner 9, the geological concept of Mars shifted to a body which had ____________-like and _______________-like topographies.
63. Geologist searching the returned photographic data for evidence
that water had flowed over the surface
found lots of evidence, such as
65. The Tharsis Ridge, where many of Mars' volcanoes are found, is
a domed up area where _______________
intruded and lifted the overlying layers several kilometers above the
mean surface level of the planet.
The Tharsis Ridge is located in Mars' equatorial region.
67. The largest of these is called ____________________. It is 15 miles in elevation and 375 miles in diameter (24 km by 600 km). At the summit there is a _______________ which is 40 miles (60 km) in diameter and which may have formed when magma retreated from the summit area of the volcano and that portion of the mountain _______________. There is another theory regarding the formation of caldera which states that the summit of the volcano, which has a slightly higher density, simply sinks into a reservoir of magma below it.
69. A volcano this massive on earth could not exist. It most likely would _________________________________________________. Since these huge volcanoes do exist on Mars, it can be assumed that the crust is _______________. Another mitigating circumstance is that the gravitational attraction on Mars is weaker.
70. Coming off of the Tharsis Ridge and paralleling the Martian equator, a great rift valley called ____________________, stretches away from the volcanic zone. It is about 2500 miles (4000 km) in length. It is probably related to Tharsis, having also been caused by the upward pressure of magma working its way towards the surface. This pressure may have been released when a graben fault formed. It may also represent a divergent plate boundary suggesting that Mars, for a very short period of time, experienced ____________________.
71. Mars possesses an atmosphere which is primarily composed of _________________.
73. Mars has many different ways in which the atmosphere circulates. One of the most interesting and unique patterns has to do with the freezing and subliming (vaporizing) of _______________ at the polar caps. As winter approaches and temperatures lower, _______________ is deposited as dry ice on the surface at one of the poles. The atmospheric pressure in that region INCREASES/DECREASES (circle one). Just the opposite situation is occurring at the other pole, so the pressure in that region INCREASES/DECREASES (circle one). Atmosphere is transported from the pole which is advancing into SUMMER/WINTER (circle one) to the other pole via a pressure gradient which is formed between these two regions.