Terrestrial Planets (2009)

1,244 views

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,244
On SlideShare
0
From Embeds
0
Number of Embeds
46
Actions
Shares
0
Downloads
44
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Terrestrial Planets (2009)

  1. 1. <ul><li>Other Terrestrial Planets </li></ul><ul><ul><li>Mercury </li></ul></ul><ul><ul><li>Venus </li></ul></ul><ul><ul><li>Mars </li></ul></ul>
  2. 2. Mercury Data http://www.vegaattractions.com/images/1mercury.gif Surface Gravity if Earth = 1 0.38 Planet Symbol (draw) Mass if Earth = 1 0.055 Length of Day 58.65 Earth days Diameter if Earth = 1 0.38 Length of Year (revolution around the sun) 87.97 Earth days Diameter at the Equator 3,031 miles Moons 0 Mean Distance from the sun 36,000,000 miles 0.4 AU
  3. 3. Discovery <ul><li>Naked eye planet </li></ul><ul><li>It was first mentioned in written records of the Sumerians (3000 BC). </li></ul>
  4. 4. Mercury is only Slightly Larger than the Moon MERCURY OUR MOON
  5. 5. Mercury Visibility <ul><li>Briefly at sunset or sunrise </li></ul><ul><li>Always close to the sun </li></ul><ul><li>Inferior planet phases provided proof of Copernican solar system </li></ul>
  6. 6. Phases of Mercury <ul><li>Inferior planet (between sun and earth), displays phases </li></ul><ul><li>Visible in telescopes </li></ul>
  7. 7. Phases of Inferior Planets http://www.polaris.iastate.edu/EveningStar/Unit1/Graphics/PicES1_6c.gif http://astromm.calstatela.edu/images/planets/larousse/Me_Phases.jpg
  8. 8. Eccentric Orbit <ul><li>Mercury’s orbit is one of the most elliptical, or eccentric </li></ul><ul><li>Perihelion, 46 million km </li></ul><ul><li>Aphelion, 70 million km </li></ul>
  9. 9. Planetary Eccentricities Which planet is most eccentric?
  10. 10. Mercury’s Lobsided Orbit www.astro.lsa.umich.edu/.../ mercury_layers.jpg
  11. 11. Mercury’s Temperature <ul><li>Extreme temp changes </li></ul><ul><li>Dayside, 840 °F (450 °C) </li></ul><ul><li>Nightside, -290 °F (-180 °C) </li></ul><ul><li>Venus is the hottest planet </li></ul>
  12. 12. Surface Features <ul><li>Mercury resembles the moon </li></ul><ul><li>Like the moon, it lacks a substantive atmosphere </li></ul><ul><li>Mercury is heavily cratered and very old. </li></ul><ul><li>Features: Scarps (enormous cliffs) </li></ul><ul><li>Caloris Basin </li></ul>http://www.r-ds.com/images/ImagesOpera/beethoven.jpg
  13. 13. Discovery Scarp
  14. 14. Caloris Basin <ul><li>About 800 miles diameter </li></ul><ul><li>Impact feature </li></ul><ul><li>Resembles lunar maria (seas) </li></ul><ul><li>Impact nearly shattered Mercury, created warped region at antipode </li></ul>http://www.record-producer.com/i/capacitor-microphone-sizzle.jpg
  15. 15. Mercury Names <ul><li>Features on Mercury named for famous writers, musicians, and painters. </li></ul><ul><li>Craters Beethoven, Homer, Mark Twain, and Matisse </li></ul><ul><li>297 named features </li></ul>
  16. 16. Caloris Basin & Antipode
  17. 17. 16 Largest Craters on Mercury <ul><li>Beethoven </li></ul><ul><li>Tolstoy </li></ul><ul><li>Raphael </li></ul><ul><li>Goethe </li></ul><ul><li>Homer </li></ul><ul><li>Vyasa </li></ul><ul><li>Rodin </li></ul><ul><li>Monet </li></ul><ul><li>Haydn </li></ul><ul><li>Mozart </li></ul><ul><li>Bach </li></ul><ul><li>Valmiki </li></ul><ul><li>Renoir </li></ul><ul><li>Wren </li></ul><ul><li>Vivaldi </li></ul><ul><li>Matisse </li></ul>
  18. 18. Shakespeare quadrangle of Mercury http://www.hollowaypages.com/images/CHANDOS2.jpg
  19. 19. Interior <ul><li>Large molten iron core </li></ul><ul><li>Mercury’s metal core dominates most of the planet’s volume </li></ul><ul><li>For earth’s core, only 17%, Mercury’s 80% </li></ul>
  20. 20. Mercury’s Day <ul><li>Mercury rotates three times in two of its years </li></ul><ul><li>Rotation = 58.65 earth days </li></ul><ul><li>Revolution = 87.97 earth days </li></ul><ul><li>Mercury experiences only three days in two of its years. </li></ul><ul><li>3(58.65) = 175.95 </li></ul><ul><li>2(87.97) = 175.94 </li></ul>
  21. 21. Spacecraft <ul><li>Mariner 10: Visited Mercury in 1975. </li></ul><ul><ul><li>Photographed 45% of surface </li></ul></ul><ul><li>MESSENGER: </li></ul><ul><ul><li>Launched 2004 </li></ul></ul><ul><ul><li>Perform 2 flybys </li></ul></ul><ul><ul><li>Orbit Mercury starting in 2011 </li></ul></ul><ul><ul><li>Homepage </li></ul></ul>
  22. 22. Mariner 10’s Mercury (all images) http://nssdc.gsfc.nasa.gov/imgcat/mission_index.html#Mariner_10
  23. 23. MESSENGER <ul><li>Launched August 2004, reached Mercury January 2008 </li></ul><ul><li>Will orbit and map Mercury </li></ul>http://ltpwww.gsfc.nasa.gov/ltp/images/Messengercraft.jpg
  24. 24. MESSENGER: Jan 2008
  25. 25. MESSENGER: Double-Ring Crater (1/14/08) http:// messenger.jhuapl.edu /
  26. 26. MESSENGER: “Spider” Crater
  27. 27. MESSENGER: Jan 2009
  28. 28. Water on Mercury!? <ul><li>Ice may exist in craters at Mercury’s poles </li></ul><ul><li>Cratered areas never receive sunlight </li></ul><ul><li>Similar deposits might exist on our Moon </li></ul>
  29. 29. Transits of Mercury <ul><li>Transit : The passage of an inferior planet (Venus or Mercury) across the face of the sun </li></ul><ul><li>For Mercury, about 13 per century </li></ul><ul><li>Last was November 2006 </li></ul><ul><li>Spaceweather Link </li></ul>
  30. 30. Lore of Mercury <ul><li>Wednesday, or Woden’s Day, is named for Mercury </li></ul><ul><li>Greeks: Evening appearance Apollo, morning appearance Hermes </li></ul><ul><li>Romans: God of commerce, travel, and thievery </li></ul><ul><li>Mercury was the quickest moving of the heavenly bodies, and the first to orbit earth in Ptolemy’s universe </li></ul>
  31. 31. Venus Data http://www.vegaattractions.com/images/1venus.gif Surface Gravity if Earth = 1 0.91 Planet Symbol (draw) Mass if Earth = 1 0.815 Length of Day 243.01 Earth days Diameter if Earth = 1 0.95 Length of Year (revolution around the sun) 224.70 Earth days Diameter at the Equator 7,521miles Moons None Mean Distance from the sun 67,200,000 miles 0.72 AU
  32. 32. Venus <ul><li>Venus : Roman goddess love and beauty </li></ul><ul><li>Naked eye planet </li></ul><ul><li>Venus is the brightest of planet as seen from earth, brightest object besides sun and the moon </li></ul>
  33. 33. Evening and Morning Star <ul><li>Evening or Morning </li></ul><ul><li>Never visible late in evening </li></ul><ul><li>Venus can extend about 45º to the east or west of the sun </li></ul><ul><li>Venus stays in the sky much longer than Mercury which sets or rises near the sun </li></ul><ul><li>Venus often pairs with the crescent moon for pretty scenes </li></ul>
  34. 34. Venus as Evening Star Venus as an evening star in the western sky after sunset
  35. 35. Venus as Morning Star Venus as a morning star in the eastern sky before sunrise
  36. 36. Changing Positions of Venus, Mercury http://www.nmm.ac.uk/upload/img/mv-orbit.jpg
  37. 37. Evening Star: Venus and Moon http://www.russellsastronomy.com/sky/April-June%20Planets.htm
  38. 38. Phases of Venus <ul><li>As an inferior planet (between sun and earth), Venus displays phases that resemble the phases of earth’s moon. </li></ul><ul><li>Visible in telescopes </li></ul><ul><li>Galileo first observed the phases of Venus in the early 1600s. He was the first astronomer to use a telescope to study the night sky. </li></ul>
  39. 39. Phases of Venus, cont. <ul><li>Galileo’s observation of the phases of Venus provided important evidence in favor of Copernicus’s heliocentric (sun-centered) theory of the solar system. </li></ul><ul><li>Ptolemaic, or earth-centered solar system would only allow crescent phases </li></ul><ul><li>Copernican system allows “full” Venus </li></ul>http://phyun5.ucr.edu/~wudka/Physics7/Notes_www/img152.gif Galileo’s Venus Sketches
  40. 40. Venus Phases, Earth and Sun Centered http://r2d2.stcloudstate.edu/~womack/astr/galileo/venuscop.jpg
  41. 41. Phases of Venus ( Click Here ) http://www.robertsilvey.com/notes/Venus02t.jpg
  42. 42. 8 year cycle & Synodic Period <ul><li>Venus orbits the sun 13 times in 8 earth years </li></ul><ul><li>Result : We witness 5 Venus events every 8 earth years </li></ul><ul><li>For example, 5 inferior conjunctions of Venus occur every 8 earth years </li></ul><ul><li>Visually, appearances of Venus repeat every 8 years on virtually the same calendar date </li></ul><ul><li>The time between successive conjunctions of a planet and the earth is termed the synodic period </li></ul>
  43. 43. Venus Synodic Period <ul><li>Venus Synodic Period = 584 days </li></ul><ul><li>Compared to earth’s year, this is a 5:8 ratio </li></ul><ul><li>5 x 584 = 2920 days </li></ul><ul><li>8 x 365 = 2920 days </li></ul><ul><li>Coincidence </li></ul>
  44. 44. 8 Year Cycle <ul><li>Image, draw a line between earth and Venus </li></ul><ul><li>Outer edge is earth’s orbit </li></ul><ul><li>Inner circle is Venus’s orbit </li></ul><ul><li>Sun in center </li></ul>http://www.dreamhawk.com/venusearth.jpg
  45. 45. Retrograde Rotation <ul><li>Venus’s rotation is 243 earth days </li></ul><ul><li>Also retrograde, rotates clockwise </li></ul><ul><li>Mystery, perhaps an impact occurred? </li></ul>
  46. 46. Earth’s Sister Planet <ul><li>Venus 95% of earth’s diameter, 80% of earth’s mass </li></ul><ul><li>Earth is heaven, Venus is hell </li></ul>
  47. 47. Atmosphere of Venus <ul><li>Venus is entirely covered with a thick atmosphere of Carbon Dioxide. </li></ul><ul><li>Surface of Venus never visible from earth </li></ul><ul><li>Magellan spacecraft used radar to map planet’s surface </li></ul><ul><li>Immense greenhouse effect, Venus’s surface temperature equals 900ºF (hot enough to melt lead). </li></ul><ul><li>Hotter than Mercury, twice as far from the sun </li></ul><ul><li>High atmospheric pressure </li></ul><ul><li>Sulfuric acid rain </li></ul>
  48. 48. Venus Greenhouse Effect http://www.uk2planets.org.uk/images/gallery/venus_greenhouse%20effect_esa.jpg
  49. 49. Cloudy Venus Venus is covered with a dense layer of clouds that hides its surface. Unlike the benign water vapor clouds on Earth, these clouds contain large amounts of sulfur dust and sulfur compounds, giving them a yellow-orange color. The clouds on Venus are made of concentrated sulfuric acid.
  50. 50. Spacecraft to Venus <ul><li>More than 20 space missions, American and Russian </li></ul><ul><li>First Mariner 2, 1962. </li></ul><ul><li>Soviet Venera 7, the first spacecraft to land on another planet, and Venera 9, returned the first photographs of the surface. </li></ul><ul><li>Magellan mapped Venus (after 1990) </li></ul>http://members.aol.com/NYRocketScience/space/1962/s199-us-mariner2.jpg
  51. 51. Mariner’s Venus http://www.solarviews.com/browse/venus/venusmar.jpg 1962
  52. 52. Venus’s Surface (Venera) http://antwrp.gsfc.nasa.gov/apod/image/0311/venus_venera13.jpg
  53. 53. Magellan Global Views http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-venus.html
  54. 54. Venusian Landscape (Magellan)
  55. 55. Venusian Crater
  56. 56. Surface Features <ul><li>Gently sloped surface, mainly lava flows </li></ul><ul><li>A few impact craters </li></ul><ul><li>Several depressions such as Atalanta Planitia . </li></ul><ul><li>Two large plateaus or highland areas ( Ishtar Terra and Aphrodite Terra ), most similar to earth’s continents </li></ul><ul><li>Several large volcanoes such as the Sif Mons, not active </li></ul><ul><li>Unique landforms such as pancake volcanoes, spider-like “arachnoids,” and coronae </li></ul>
  57. 57. Equatorial Venus
  58. 58. Venus Volcanism (all images) http://nineplanets.edu
  59. 59. Unusual Volcanism, Pancake Domes
  60. 60. Corona and Arachnoid
  61. 61. Early Fancies <ul><li>A swampy world with dinosaurs </li></ul><ul><li>Pure fantasy </li></ul>
  62. 62. Transits of Venus <ul><li>Venus transits occur twice in 8 years, separated by over 120 years </li></ul><ul><li>One of the rarest events in astronomy </li></ul><ul><li>Last transit of Venus occurred June 8, 2004, the next will be in 2012 </li></ul><ul><li>Previous transit had been in 1882 </li></ul>
  63. 63. June 2004 Transit of Venus http://www.atmob.org/Photo/venus_2004/venus%20transit%208.JPG
  64. 64. Transits of Venus 8 June 9, 2255 122 June 11, 2247 8 December 8, 2125 105 December 11, 2117 8 June 6, 2012 June 8, 2004 Separation in Years Transit Dates
  65. 65. Feminist Planet <ul><li>Surface features named after women </li></ul><ul><li>Ex : Amelia Earhart and Sacajawea, also ancient goddesses such as Ishtar and Aphrodite </li></ul>http://www.feministcampus.org/images/egreeting/rosie_the_riveter.jpg
  66. 66. “Personality” of Venus <ul><li>Rises quickly and is very brilliant </li></ul><ul><li>High in the sky for a few months, sinks rapidly to disappear. </li></ul><ul><li>Moves back and forth between morning and evening sky (about 9 months in each) </li></ul><ul><li>Behavior interpreted in mythology (Maya, Sumerian) and Paradise Lost </li></ul>
  67. 67. Lore of Venus <ul><li>Sumerians : Goddess Ishtar, conjunctions represented the goddess's death and rebirth </li></ul><ul><li>Greeks : Hesperus in the evening sky, Phosphorus in the morning sky </li></ul><ul><li>Maya : God Quetazlcóatl (winged serpent) </li></ul><ul><li>Maya Venus Calendar (Dresden Codex) </li></ul>
  68. 68. Goddess Ishtar http://www.unige.ch/lettres/antic/mesopotamie/ishtar.jpg
  69. 69. Maya Venus, Dresden Codex http://www-groups.dcs.st-and.ac.uk/~history/Diagrams/Dresden.jpeg
  70. 70. Maya Venus “Observatory” at Chichen Itza http://centros.edu.aytolacoruna.es/sfxabier/world_links/mexico_observatory.jpg
  71. 71. Lore of Venus: Paradise Lost <ul><li>Milton : The movement of Venus in the sky was used as a metaphor of the fallen angel Lucifer </li></ul><ul><li>Central theme of epic poem Paradise Lost </li></ul><ul><li>Published in 1674, the poem deals directly with ideas from the Bible </li></ul>
  72. 72. Paradise Lost http://www.clt.astate.edu/wnarey/Honors%20Seminars_files/Horror/summar3.jpg http://users.ox.ac.uk/~lina0897/emwo/images/big/PARADISE_LOST.jpg
  73. 73. Mars Data http://www.vegaattractions.com/astrology/symbols.html Surface Gravity if Earth = 1 0.38 Planet Symbol (draw) Mass if Earth = 1 0.107 Length of Day 24 hr. 37 min. 22.6 sec. Diameter if Earth = 1 0.53 Length of Year (revolution around the sun) 686.98 Earth days Diameter at the Equator 4,217 miles Moons 2 Mean Distance from the sun 141,500,000 miles AU
  74. 74. Red Planet <ul><li>God of War : Mars was the Roman god of war </li></ul><ul><li>Discovery : Mars has been known since prehistoric times </li></ul><ul><li>A favored location for science fiction stories </li></ul><ul><li>Becomes very bright about every two years (opposition) </li></ul>
  75. 75. Spacecraft <ul><li>Mariner 4, 1965 </li></ul><ul><ul><li>No canals </li></ul></ul><ul><li>Viking landers, 1976 </li></ul><ul><ul><li>Twin landers, sampled soil, no life </li></ul></ul><ul><li>Mars Pathfinder, 1997 </li></ul><ul><ul><li>First rover mission </li></ul></ul><ul><li>Spirit & Opportunity, 2004 </li></ul><ul><ul><li>Twin rovers </li></ul></ul><ul><li>Phoenix, 2007 </li></ul><ul><ul><li>Martian Arctic, sampled soil and ice </li></ul></ul>
  76. 76. Mariner 4 : No Canals (1965) http://mpfwww.jpl.nasa.gov/MPF/martianchronicle/martianchron2/issue2images/mariner4photo.jpeg
  77. 77. Viking (1976) http://www.hypography.com/bilder/viking_on_mars.jpg
  78. 78. Pathfinder (1997) http://users.bigpond.net.au/Nick/Mars/Pathfinder.jpg
  79. 79. Pathfinder (Mars or Arizona?) http://anw.com/mars/images/widescene.jpg
  80. 80. Mars Exploration <ul><li>In 2004 the Mars Expedition Rovers &quot;Spirit&quot; and &quot;Opportunity&quot; landed on Mars sending back geologic data and many pictures </li></ul><ul><li>Spirit and Opportunity are still operating </li></ul>http:// marsrovers.jpl.nasa.gov/home/index.html
  81. 81. Spirit & Opportunity <ul><li>Panoramic Photos </li></ul><ul><li>http://antwrp.gsfc.nasa.gov/apod/ap040318.html </li></ul><ul><li>http://antwrp.gsfc.nasa.gov/apod/ap040114.html </li></ul><ul><li>http://antwrp.gsfc.nasa.gov/apod/ap040204.html </li></ul>
  82. 83. Mars Phoenix, 2007 Phoenix, location near north pole of Mars
  83. 84. Mars Phoenix
  84. 85. Phoenix: Ice on Mars
  85. 86. Mars Missions
  86. 87. Cold Planet <ul><li>Climate : Range from –207ºF at the winter pole to 80ºF on the day side during summer </li></ul><ul><li>Average temperature is –67ºF </li></ul><ul><li>Most earthlike, despite cold </li></ul><ul><li>Mars has earthlike tilt (25.19  ) and four seasons </li></ul>
  87. 88. Dusty Planet <ul><li>Atmosphere : Thin, mostly of carbon dioxide (95.3%) plus nitrogen (2.7%) and various other gases </li></ul><ul><li>Strong winds and immense dust storms that can cover most of the planet and last for many months </li></ul><ul><li>Dust devils </li></ul>
  88. 89. Mars Dust Storm
  89. 90. Martian Seasons Large ice cap made mostly of frozen carbon dioxide (dry ice) The dry ice melts, leaving a much smaller polar cap
  90. 91. Surface Features <ul><li>Surface: Nearly same land surface area as earth </li></ul><ul><li>Old and cratered </li></ul><ul><li>Resembles lunar highlands on earth’s moon </li></ul><ul><li>Younger features such as rift valleys, ridges, hills, and plains. </li></ul><ul><li>Unique and interesting, Olympus Mons, Valles Marineris </li></ul>
  91. 92. Impact Craters on Mars Most of these craters are found in the Southern Hemisphere, suggesting that the northern vastness has been resurfaced.
  92. 93. Olympus Mons http://www.physast.uga.edu/~jss/1010/ch10/mtoly.jpg
  93. 94. Tharsis Region Olympus Mons & clouds
  94. 95. Vallis Marineris (Viking)
  95. 96. Mars Volcanism <ul><li>Mars appears to lack plate tectonics, reason for huge volcanoes such as Olympus Mons. </li></ul><ul><li>Plate motions wouldn’t allow such large piles of lava to accumulate </li></ul><ul><li>No active volcanism has been observed on Mars </li></ul>
  96. 97. Martian Water <ul><li>Dry river and stream beds </li></ul><ul><li>Large lakes or oceans may have existed </li></ul><ul><li>Ice Caps : Permanent ice caps at its north and south poles. </li></ul><ul><ul><li>Mainly carbon dioxide (dry ice) with a small amount of frozen water ice </li></ul></ul><ul><li>Sedimentary rocks </li></ul>
  97. 98. Water Features Martian winding canyon, photographed by the Viking orbiter The Yangtze River in China has similar features
  98. 99. Ancient Waterways? An ancient lake A dried riverbed Sedimentation
  99. 100. Layers of rock laid down by water Hemetite black rocks, usually formed in water Gullies in crater walls
  100. 101. Sedimentary Layers from Water http://science.nasa.gov/headlines/images/mars_water/sediments.jpg
  101. 102. Chyrse, “Teardrop” Islands http://www.esa.int/images/mars_water_400.jpg
  102. 103. Martian Ice
  103. 104. Martian Life? <ul><li>Viking landers performed experiments to determine the presence of live, results inconclusive </li></ul><ul><li>Some meteorites originated on Mars </li></ul><ul><li>In 1996, NASA scientists announced the discovery of organic compounds and fossilized microorganisms in Martian meteorite ALH84001 </li></ul><ul><li>Controversial </li></ul>
  104. 105. Viking Lander
  105. 106. Viking Life Experiment Trenches http://www.physics.uc.edu/~hanson/ASTRO/LECTURENOTES/ET/Earth/VikingMarsBig.jpg
  106. 107. Meteorite from Mars! http://www.universetoday.com/am/uploads/meteorite.jpg http://www.newscientist.com/data/images/ns/cms/dn8004/dn8004-1_440.jpg
  107. 108. Martian Life? (ALH84001) http://www.lpi.usra.edu/lpi/meteorites/Photomicrograph.gif
  108. 109. Fear & Panic <ul><li>Mars has two small moons </li></ul><ul><li>Discovered in 1877 by Asaph Hall </li></ul><ul><li>Phobos and Deimos—Fear and Panic—after two sons of the god of war mentioned in Homer’s Iliad . </li></ul><ul><li>Small satellites (Phobos is only 24 miles across), resemble asteroids </li></ul><ul><li>Similar to moons in Gulliver’s Travels (1726) </li></ul>
  109. 110. Phobos & Deimos http://www.sarkanniemi.fi/oppimateriaali/tahtiakatemia/kuvat/aurinkokunta/deimos_phobos.jpg http://perso.wanadoo.fr/pgj/phobos-deimos-061105.gif
  110. 111. Martian Names <ul><li>Martian Nomenclature : System of Schiaparelli. </li></ul><ul><li>Imaginary and real place names from Greek and Roman literature </li></ul><ul><li>Ex : Solis Lacus (Lake of the Sun), Aurorae Sinus (Bay of Dawn), Margaritifer Sinus (coast of India), Syrtis Major (Gulf of Sidra), Mare Tyrrhenum (Tyrrhenian Sea), Hellas (Greece), Eden and Elysium </li></ul>
  111. 112. Observing Mars <ul><li>Mars in the Night Sky : Every two years, Mars gets very bright and easily visible. </li></ul><ul><li>Oppositions, earth and superior planet at minimum distance apart </li></ul><ul><li>At opposition, superior planet rises in the east as the sun sets in the west </li></ul>
  112. 113. Oppositions of Mars <ul><li>Future Oppositions </li></ul><ul><li>7 Nov 2005 </li></ul><ul><li>24 Dec 2007 </li></ul><ul><li>29 Jan 2010 </li></ul><ul><li>3 Mar 2012 </li></ul><ul><li>8 April 2014 </li></ul><ul><li>22 May 2016 </li></ul><ul><li>27 July 2018 </li></ul><ul><li>13 Oct 2020 </li></ul>
  113. 114. Viking’s Face on Mars (1976) http://mcadams.posc.mu.edu/images%5Cface_mars.jpg
  114. 115. Face the Truth Apparent “face” on the Martian surface 22 years later, with improved technology the feature looks more natural
  115. 116. Alien with Spirit?
  116. 117. Life on Mars?

×