Mars Pathfinder Science Results · Two years later, Soviet probe Mars 3landed a cap- sule on Mars...
Embed Size (px)
Transcript of Mars Pathfinder Science Results · Two years later, Soviet probe Mars 3landed a cap- sule on Mars...
species (presumably Homo erectus) from which Ne-andertals and humans evolved, was at least as greatas that of modern humans.
Bowler, Peter J. Theories of Human Evolution. Baltimore: JohnsHopkins University Press, 1986.
Dobzhansky, Theodosius. Mankind Evolving. New Haven,Conn.: Yale University Press, 1962.
Leakey, Richard E., and Roger Lewin. Origins: What New Dis-coveries Reveal About the Emergence of Our Species andIts Possible Future. New York: Dutton, 1977.
Lewin, Roger. Bones of Contention. New York: Simon &Schuster, 1987.
—. In the Age of Mankind: A Smithsonian Book of HumanEvolution. Washington, D.C.: Smithsonian Books, 1988.
—. Principles of Human Evolution: A Core Textbook.Malden, Mass.: Blackwell Science, 1998.
Shreeve, James. The Neanderthal Enigma. New York: WilliamMorrow, 1995.
Smith, Fred H., and Frank Spencer, eds. The Origin of ModernHumans. New York: Alan Liss, 1984.
Stringer, Christopher B. In Search of the Neanderthals. Lon-don, England: Thomas and Hudson, 1993.
Tanner, Nancy M. On Becoming Human. New York: Cam-bridge University Press, 1981.
Tattersall, Ian. The Last Neanderthal. New York: Macmillan,1995.
Trinkaus, Erik, and Pat Shipman. The Neanderthals. New York:Alfred A. Knopf, 1993.
Graves, Peter. “New Models and Metaphors for the NeanderthalDebate.” Current Anthropology, 1991, 255–274.
Hublin, John J. “A Late Neanderthal Associated With UpperPaleolithic Artifacts.” Nature, May 16, 1996, 224–226.
Kahn, Patricia, and Ann Gibbons. “DNA From an Extinct Hu-man.” Science, July 11, 1997, 176–178.
Klein, Richard G. “Neanderthals and Modern Humans in WestAsia.” Evolutionary Anthropology, 1995/1996, 187–193.
Schwartz, Jeffrey H., and Ian Tattersall. “Significance of Pre-viously Unrecognized Apomorphies in the Nasal Region ofHomo neanderthalensis.” Proceedings of the National Acad-emy of Science, October 1996, 10852–10854.
Smith, Fred H. “The Neanderthals: Evolutionary Dead Ends orAncestors of Modern People?” Journal of AnthropologicalResearch, 1991, 219–238.
Stringer, Christopher B., and Robert Grun. “Time for the LastNeanderthal.” Nature, June 27, 1991, 701–702.
Weaver, Kenneth F., et al. “The Search for Early Man.” Na-tional Geographic, November 1985, 560–629.
“The Human Origins Program.” National Museum of NaturalHistory. Smithsonian Institution. Available online at http://
www.mnh.si.edu/anthro/humanorigins; website home page:http://www.mnh.si.edu (accessed July 15, 2003).
“Lucy in the Earth.” A Science Odyssey. Available online athttp://www.pbs.org/wgbh/aso/tryit/evolution/lucy.html; web-site home page: http://www.pbs.org/wgbh/aso/ (accessedJuly 16, 2003).
Walker, Phillip L., and Edward H. Hagen. “Human Evolution:The Fossil Evidence in 3D.” Department of Anthropology.University of California, Santa Barbara. Available online athttp://www.anth.ucsb.edu/projects/human; website homepage: http://www.anth.ucsb.edu (accessed July 15, 2003).
Mars Pathfinder ScienceResultsPhotographs
By: National Aeronautics and Space Administration (NASA)Date: October 1997Source: Photri Microstock. Available online athttp://mars.jpl.nasa.gov/MPF/ops/prm-thmb.html; websitehome page: http://mars.jpl.nasa.gov (accessed July 30, 2003).About the Organization: In 1958, Congress created NASAto recapture U.S. leadership in the space race after the SovietUnion (U.S.S.R.) stunned the United States and the world, in1957, by launching the world’s first intercontinental ballisticmissile and satellite, Sputnik. NASA launched the first probesto Mars in 1964 and landed the first man on the moon in1969. NASA launched the first space shuttle in 1981, andlanded Pathfinder and Sojourner on Mars in 1997. NASAplanned subsequent probes to Mars in 2003 and 2005. ■
IntroductionAmerican astronomer Percival Lowell stimulated in-
terest in Mars. Through his telescope at the Lowell Ob-servatory at Flagstaff, Arizona, Lowell in the 1890sbelieved he saw a network of canals. Intelligent beingsmust have built them, he reasoned, evidencing that Marsonce harbored life and, perhaps, still did.
During the space race between the United States andthe U.S.S.R., both nations sought to expand their knowl-edge of Mars. In 1958, Congress created NASA to leadthe American charge into space. In 1964, NASAlaunched Mariner 3, the first of its probes intended forMars. Technical problems scuttled Mariner 3, a loss thatdid not deter NASA from launching Mariner 4 in No-vember 1964. In July 1965, it flew within 6,000 miles ofMars—photographing Mars’ surface in more detail thanany telescope on Earth could hope to achieve. These pho-tos showed Mars to be cratered like the moon. Mariner 4detected an atmosphere only 1 percent as dense as Earth’s.In 1969, NASA launched Mariner 6 and 7 for Mars.
Mars Pathfinder Science Results
Science and Technology ■ 573American Decades Primary Sources, 1990–1999
Two years later, Soviet probe Mars 3 landed a cap-sule on Mars during a dust storm that disabled the cap-sule after twenty seconds. In 1974, Soviet probe Mars 5orbited Mars, detecting a weak magnetic field on theplanet—implying that Mars had once had a radioactivecore that melted rock and metals, including iron in its in-terior. The movement of molten iron inside Mars gener-ated a magnetic field.
Meanwhile, in 1972, Mariner 9 became the firstU.S. probe to orbit Mars, sending back more than 7,000photos of its surface. Mariner 9 revealed that Mars hadvolcanoes, evidence that Mars had once had a radioac-tive core whose pressure and heat vented through vol-canoes, evidence that Mars 5 corroborated. In 1975,NASA launched Viking 1 and 2, both of which set land-ing craft on Mars. The crafts tested soil samples and
rock, and the probes relayed photos back to Earth, Viking2 until 1980.
SignificanceNASA crowned these efforts, landing Pathfinder on
Mars on July 4, 1997. Pathfinder released Sojourner, thefirst automated rover, to analyze and photograph soil androck. The first of the accompanying photos shows So-journer on its approach to a Martian rock. Other photosfrom Pathfinder and Sojourner reveal that wind haseroded Martian rocks, further evidence of Mars’ atmos-phere. Other rocks display pits and pebbles alongsidethem that scientists believe wind may have dislodgedfrom larger rocks. Between July 4 and October 7,Pathfinder and Sojourner relayed some 16,000 photos toEarth, the largest collection from a single probe.
Mars Pathfinder Science Results
574 ■ Science and Technology American Decades Primary Sources, 1990–1999
Primary SourceMars Pathfinder Science ResultsSYNOPSIS: The first of these three photos shows Sojourner on its approach to a Martian rock nicknamed “Yogi” on July 9,1997. To the rover’s immediate left is the smaller rock called “Barnacle Bill.”At the lower left corner of the image is theramp used by Sojourner to drive off Pathfinder. Other photos from Pathfinder and Sojourner reveal that wind has erodedMartian rocks, further evidence of Mars’ atmosphere. COURTESY OF PHOTRI MICROSTOCK. REPRODUCED BY PERMISS ION.
Mars Pathfinder Science Results
Science and Technology ■ 575American Decades Primary Sources, 1990–1999
Primary SourceMars Pathfinder Science ResultsClose-up of the rock “Yogi,” taken by Sojourner on July 9, 1997. Sojourner used its Alpha Proton X-Ray Spectrometer (APXS)instrument to conduct a study of Yogi’s chemical composition. The rover’s track marks are also visible in the foreground.Multiple soil mechanics experiments were performed by Sojourner’s cleated wheels at this location. COURTESY OF PHOTRI MI -CROSTOCK. REPRODUCED BY PERMISS ION.
Primary SourceMars Pathfinder Science ResultsOne of Sojourner’s two front cameras took this image of several large rocks on July 10, 1997. The lander and its deployedrear ramp are at the upper left. The rover was near the rock “Yogi” when the image was taken. COURTESY OF PHOTRI MICRO-STOCK. REPRODUCED BY PERMISS ION.
That year NASA’s Mars Global Surveyor began or-biting Mars with the objective of mapping its entire sur-face. With these maps, NASA scientists hoped to identifylanding sites for probes they intended to launch in 2003and 2005.
The exploration of Mars, from Mariner 4 toPathfinder, reveals that Mars was once like Earth in hav-ing liquid water, a radioactive core, and active volcanoes.These conditions, along with an atmosphere, may have per-mitted the evolution of microbial life, a humble step wellbelow the intelligent beings Percival Lowell had envi-sioned. Some scientists believe a Martian asteroid containstiny etchings left by microorganisms, though others con-tend these etchings resemble those on lunar rock, whereno life existed. Even if Mars once harbored life, scientistsbelieve none now exists on the barren, arid planet.
Hamilton, John. The “Pathfinder” Mission to Mars. Min-neapolis, Minn.: Abdo & Daughters, 1998.
Pritchett, Price. The Mars “Pathfinder.” Dallas, Tex.: Pritchett& Associates, 1998.
Shirley, Donna. Managing Martians. New York: BroadwayBooks, 1998.
Arvidson, Raymond E., et al. “The Surface of Mars.” ScientificAmerican, March 1978, 76–89.
James, J.N. “The Voyage of Mariner IV.” Scientific American,March 1966, 42–52.
Wilson, Nigel. “Shark Bay May Hold Clue to Life on Mars.”Australian, November 13, 2002, 4.
“Mars Atmospheric and Geological Imaging.” Lunar and Plan-etary Laboratory. University of Arizona. Available online athttp://www.lpl.arizona.edu/IMP; website home page: http://www.lpl.arizona.edu (accessed July 16, 2003).
“Mars Missions—Past, Present, and Future.” Available onlineat http://mars.sgi.com (accessed July 16, 2003).
“Mars Pathfinder.” Live from Earth & Mars. Available onlineat http://www-k12.atmos.washington.edu/k12/mars/pathfinder.html; website home page http://www-k12.atmos.washing-ton.edu/k12 (accessed July 16, 2003).
“Mars Pathfinder.” MarsNews.com. Available online at http://www.marsnews.com/missions/pathfinder; website homepage: http://www.marsnews.com (accessed July 16, 2003).
Williams, David R. “Mars Pathfinder Images.” National SpaceScience Data Center. National Aeronautics and Space Ad-ministration. Available online at http://nssdc.gsfc.nasa.gov/planetary/marspath_images.html; website home page: http://nssdc.gsfc.nasa.gov (accessed July 16, 2003).
Williams, David R. “Mars Pathfinder Project Information.” Na-tional Space Science Data Center. National Aeronautics andSpace Administration. Available online at http://nssdc.gsfc.nasa.gov/planetary/mesur.html; website home page:http://nssdc.gsfc.nasa.gov (accessed July 16, 2003).
“Pathfinder Arrives at Mars.” SpaceViews. Available online athttp://www.seds.org/spaceviews/pathfinder; website homepage: http://www.seds.org/spaceviews (accessed July 16,2003).
“14 Answers From GarryKasparov”Interview
By: Garry KasparovDate: 1997Source: Kasparov, Garry. “14 Answers From Garry Kas-parov.” Interview by Spiros Tzelepis. Available online athttp://users.otenet.gr/~tzelepisk/yc/kasp.htm; website homepage: http://users.otenet.gr (accessed July 15, 2003).About the Author: Garry Kasparov (1963– ) was born inBaku, Azebaijan, a former Soviet republic. At nine, he won asemifinal of the Blitz championship for adults in Baku, and attwelve he won the Soviet Junior Championship, the youngestplayer to win this title. In 1980, he won the World JuniorChampionship and, in 1985, rose to be the world’s highest-ranked chess player, a position he held into the early twenty-first century. ■
IntroductionThe fascination with computers stems, in part, from
the possibility that humans might build computers withan intelligence equal to or greater than their own. Shouldcomputers reach such a stage, they would presumablythink and behave like humans and even display emotions.Many people doubt computers will ever exhibit these ca-pabilities, but Tulane University mathematical physicistFrank J. Tipler disagrees.
Tipler attributes the inability of computers to thinkand behave like humans to the fact that they do not yethave the memory or speed of the human brain—able tocode some 1017 bits of information in its memory and toprocess information at 10 trillion floating point opera-tions per second (flops). Today’s computers cannot matchthese numbers, though Tipler expects them to equal thesenumbers by 2030.
At that date, assuming Tipler is right, computers willbe able to pass a test British mathematician and computerscientist Alan M. Turing devised in 1950. He imaginedtwo rooms, one with a person and the other with a com-puter. Someone outside these rooms attempts to engagethe occupants of both rooms in conversation in hopes ofdistinguishing the person from the computer. But, if aftermonths of dialogue, he cannot identify which room con-tains the person and which the computer, he must concludethat the computer has equaled humans in language—implying that it has equaled humans in intelligence.
“14 Answers From Garry Kasparov”
576 ■ Science and Technology American Decades Primary Sources, 1990–1999