Table of Contents

Mecury, Venus, Mars

Intro to Astronomy

Equitorial Coordinates
Understanding the Seasons

Time & Its Measurement


Solar & Lunar Eclipses

The Solar System

The Earth

The Moon  

The Outer Planets

Solar System Debris

The Sun

Evolution of Stars

Intersteller Matter

Sky Literacy

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
    as we observe it from earth..
      a. When Mercury is between the earth and the sun, its phase would be the same as when
      the moon is ________________.
      b. When Mercury is on the opposite side of the sun, its phase is _______________.
      c. When the sun-Mercury-earth angle is equal to 90 degrees, the phase of Mercury is       ________________.
    Just like the moon, the amount of time that it takes Mercury, or any other planet, to repeat a     cycle of phases is equal to the synodic period of that object.

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.

8. At perihelion, the positions which are located directly under the sun receive 2.5 times the     insolation (energy from the sun) than the locations which appear under the sun at aphelion..     Because of Mercury's locked rotation/revolution, two key equatorial regions are alternately     exposed to the noonday sun at perihelion. One of these hot spots is named     ____________________.

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 of Mercury.

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.
      a. Crustal formation and crater saturation
      b. Impact of large asteroid bodies
      c. Accretion from the cooling solar nebula
      d. Planet becomes a geologically dead world
      e. Period of planet-wide volcanism

Moon: _______, _______, _______, _______, _______
Mercury: _______, _______, _______, _______, _______

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 is a
      diff_______________ world. It can be said that all of the planets and most of the moons in our       solar system were massive enough to be hot enough in their early histories to have produced this       phenomenon.

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.
      a. Train approaches: ____________________________________________
      b. Train recedes: ____________________________________________

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.
      a. _________________ c. _________________
      b. _________________ d. _________________

29. A particular gas on Venus called ___________________ is chiefly responsible for artificially       elevating temperature on the planet. The temperature on Venus is approximately       ____________________.

30. Venusian volcanoes probably outgassed as much water vapor as terrestrial volcanoes, yet       Venus evolved so differently from earth. Higher initial temperatures prevented it from       _______________ on the planet. Water was driven to higher altitudes where it was       ____________________ by ultraviolet energy from the sun, allowing the hydrogen to escape.       The _______________ most likely combined with other molecules and atoms, thus further       drying the atmosphere of the planet. Because the earth experienced an epoch of rain, CO2 was       dissolved into the rainwater where it was able to enter the ground to form carbonate rocks.

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)       _______________________________________________________________
      This is another factor as to why Venus is so hot at its surface.

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).

45. Magellan has shown in startling detail the dynamic surface features of Venus which possess       volcanoes, massive lava flows, mountain ranges, and chasms. There are few impact craters on       Venus' surface as compared to other terrestrial planets such as Mercury and Mars. This would       indicate that Venus' surface is geologically YOUNG/OLD (circle one).

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.
      a. _______________________________________________________________
      b. _______________________________________________________________
      c. _______________________________________________________________

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
      a. _____________________________________________________________________
      b. _____________________________________________________________________
      c. _____________________________________________________________________

64. Changes brought about by wind could be identified on the planet's surface by observing       _______________________________________________________________________

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.

66. Where the surface became most fractured _______________ (geologic feature) arose to stand       high above the Tharsis Ridge.

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.

68. The lava which formed Olympus Mons had a HIGH/LOW (circle one) viscosity.
      Remember, viscosity is the resistance to flow that a material possesses in the liquid phase       (state).

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 _________________.

72. Like Venus, Mars' atmospheric temperature is raised because it retains some of the       _______________ energy (specific type) which is radiated from its surface. Mars' temperature       is raised by only 9° F (5° C), compared to a huge 900° F (500° C) rise for Venus. The       difference in the ability of the greenhouse effect to raise the temperature of Mars' atmosphere is       a result of its low _______________.

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.