DOCUNEIT XESUNE s. ED 124'429 - '51 020 993 TITLE NASA Facts',,Kars as a Planet" NSTITUTION National Aeronautics and Spaqe Administration, Washington, D.C. Educational'PiogramsDiv.- REPORT NO . _IF-60/8-75 PUB DATE [76'] - --NOTE .13p.; Not available in -hard copy due to nrginaV - . 'I . - . legibility AVAILABLE-FROM. Racnments._.U.S.'Governient Printilkl___ Office, Washington, D.C. 20402 - (Stock lb. 033-000-00623-34 $0.35). 'BURS PRICE MP-$O. 83 Plirr.7Postage:.HC Not Available from EDRS. DESCRIPTORS \Aerospace Technology; *Astronomy; Earth-S 'ence; *Instructional Materials; Science Education; *Scientific\Besearch; *Secondary School Science;- *Space Sciences IDENTIFIERS *Mars; Solar System ABSTRACT Presented is one of a series of National Aeronautics and Space Administration (NASA) facts about the exploratioh of Nars.. Photographs, showing Mars as seen from Earth tb\rough a telescope, show dark markings and polar caps.present. Photographs from Mariner 7, Mariner 4, and Mariner 9 are included. Presented is a compositeof several Mariner 9 photographs that reveal tile .summit craters andthe cliffs at the base of a high-pile of lava `with an altitude trace scheme drawn across a mountain dia ram:4ex lanation of the changes .occurrin'gon Mrs on the basis of c ose-up o serva ions y Mariner 9is presented. Both the geology and atmosphere of Mars are described. A contour napshowing the highest contours j.5 kilometers above andbelow the level on Mars et which water can exist as a liquid isincluded: Student involvement is facilitated by the inclusionof three suggested activities and suggested readings. (EB) **************************************************45**#**************** * . * Documents acquired by ERIC include many informal unpUblished. * .materials not available,frow other sources. ERIC Rakesevery effort * * to. obtain the ,best copy available. Nevertheless, items -ofmarginal * * reproducibility are often encountered and thisaffects the quality* * of the microfiche and hardcopy reproductions ERIC makesavailable * * via.,.thre ERIC Document Reproduction Service (EMS). EDRS is not. * * responsible for the quality of the oFiginaldocument; Reproductions * * supplied by EDRS are the best that can bemade fiom the original. * *******44*************************************************************** 121. U.S DEpARTMEKTOF NEAL/H. EDUCATION t WELFARE ItfriONALINSTITUTEOF EDUCATION THIS DOCUMENT k1AS SEEN REPRO- ,DuCED ExAtTLy AS RECEIVED FROM An Educational Publi Cabon /THE PERSON OR ORGANIZATION ORIGIN. .of the Almo IT POINTS OF VIEW OR OPINIONS ST,ATE0 DO NOT NECESSARILY REPRE- National Aeronautics and .SENT OFF ociAL. kATIONAL oNSTaTUTE OF Space Adminstration EDUCATION POSITION OR POLICY NF -60/8-75 C\I ,-i-i-MARS AS. A PLANET ,c=1 One of a series of NASA Facts about the explore- . Iron of Mars, Surface Features -of Mars Some astronomers Claimed that they could see linearmarkingscriss-crossingtheplanetin The first great change in human attitude toward intricate, geometrical patterns, .marki,ngs which the planets came in the seventeenth century. With were popularly called canals, from the Italian the. invention pf the telescope the planets were "canali" or "channels." A few, such as Percival seen to have size, they were no longer points of Lowellih the last century, believed that these linear lightilke the stars, but worlds that might be similar markings were evidence of intelligent beings on to the Earth. The second great change came with Mars conserving water supplies on a dying planet. the space age when close inspection of the planets This :viewpoint was not, however, accepted by the .by spacecraft changed them from remote and majority of astronomers. distant worlds to places that could be explored. Mars, too, was known to possess an atmosphere. The first record of anyone seeing features on _Photographs taken in ultraviolet light, which does ,.the surface of Mars. is that of Christian Huygens, not, penetrate an atmosphere welt, showed a 'a Dutch physicist and astronomer. In 1659 he made larger disc to Mars than photographs taken in aroucjtkatch_'-0 infrarQd ht whi h .en- r t now known as the Syrtis Major ("Great Quick- face. Moreover, astronomers often observed light sands"). markings., and, hazes' which they interpreted as clouds.and dust in the-atmosphere of Mars. The .features on Mars are digi.cult to observe with small telescopes because although Mars The first spacecraft to reach Mars, NASA's approaches close .to Earth compared with most Mariner4(1965), provided only-e limited number other planets of the Solar System, its physical of telescopic close-ups across the Red Planet. size is small: a little more tha,n half the diameter of None of the familiar markings that astronomers ,Earth. Classical markings on Mars (Figure 1) ap- see from Earth could be identified. But many of pear dark grey or bluish green upon a reddish- the pictures showed craters similar to those on ocher background with white polar caps-that vary the Moon. Many scientists erroneously concluded in size with .the Martian seasons. that Mars was a moon-like body; itssurface shattered and splattered by the impact of large The first major map of Mars was published by bodies falling,from. space; some the size of small Wilhelm .Beer and J. H. von Maedler in 1840. But mountains. A few pointed out, however that there this map bears little resemblance to the Martian was evidence of linear features on Mars (Figure 2) features now mapped in great detail by NASA's that could be faults such at those that. border Mars-orbiting spacecraft, Mariner 9. rift valleys on Earth, and that these might be Before this spacecraft produced detailed pic- evidence of vulcanism on Mars. tures of Mars, controversy raged fortmany years Subsequent NASA spacecraft, Mariners 6 and on the nature of the illusive Martian markings; 7 (1969), again revealed heavily- cratered terrain, especially since their intensities and shapes ap- hut with some unusual features that were difficult peared to vary with seasons on Mars. And.another to explain if the Martian surface had been formed great controversy raged on the nature of the sea- solely by the impact of large meteorites;In places, sonal polar caps as to whether they were of ice Mars seemed to have collapsed inwards to pro- and snow like Earth's caps, or of frozen carbon duce complex patterns of fractures and slumped 'dioxide. terrain. Additionally, these pictures revealed that 1 fec.f Figure 1.Mars as seen from Esith through a leisscops shows dark markings and polar caps. Thesl yary with the seasons on Mars. This sides of Mariner 7 pictures' shows rotation of' Mars at about the same resolution. ' . 2 3 , O J.*? thepol ps,probably consisted of thin carbon- old tennis ball with no visible details except for clkod e snow which disappears quickly, but with a faint polar cap. The spacecraft had arrived when 2a.pennanent ice cap over a much smaller area Mars was engulfed in a monstrous wind storm of of each polarregion.Peculiar. ridges near the which shrouded the whole of the planet, 'with cloufs poles_suggastad that the ice caps may be layered of sand and duit (Figure 3). with dust The storm had,started in regions called Helles- In 1971 Mariner 9 went into orbit ardund Mars pontus and Noachis in the sOutbarn hemisphere, and began a detailed photographic survey of the and then spread rapidly to engulf all the planet. As Martian surface. The first pictures were disappoint- seen from Eattli,detailed markings on Mars . ing.Mars showed a uniform, image resembling an jaded. As seen from Mariner 9, the yellowish cloud " Figure 2.The first spacecraft (Marinir 4) to arrive at Mars, showed large eaters but 240 hinted at volcanic acth4ty by the - presence of a lineament cutting diagonally across the bottom right-hand corner of. the picture. 0 4 3 obscured everything, except for the *south poly major storms may occur, each year on Mars, but cap and four dark 'spots. are not so easily observed from Earjh when Mars is not at the close (perihelic) oppositions. Intense dust' storms had also been observed on Mars. in 1892, 1924, 1941, and 1956, and later in elradually the 1971storm cleared and a group 1973. Each engulfed the planet when Mars was of huge volcanoes was seen, their cratered peaks at its closest to the Sun (perihelion). It seems that projecting rifiles'abOve the settling dust fn sub- . Figure 3. When Mariner I arrived at Mars in 1.71 the planet was shrouded in duit and only the south polar capand,four dark spots were visible. .4 5 ,, , . ,... , ,. , 11 'Zi! sequent months a completely new interpretation come. Even. on Earth, volcanoes often- remain of the Martian features had to be accepted. Mars dormant for centuries between eruptions. could not be considered a dead world. About half 'of the planet's surface is Very old and heavily Another newly-discovered feature on Mars is a cratered, much like the highlands or the backside unique super Grand Canyon that stretches across of the Moon. The other half is. younger terrain the planet a distance equal to the width of the containing the biggest volcano known and the United States. The, canyon (Figure 5) is 120 kilo- meters (75 'miles) wide and 6 kilometers (4* miles) , equivalent of ocean basins, fractured and over- lain with sedimentery and wind-borne deposits. deep. Its wane show evidence of erosion as though streams of *water have flowed into it from the .The big volcano (Figure 4) is seen from Earth Surface and from underground sources. Also at its as a light spot on Mars. It was called Nix Olympica eastern end the material that was_washed from It (Snows of Olympus) but has.baeruenamedOlym appears to be deposited in great plains extending pus Mons (Mount Olympus) since it is holirkti-own .northWard toward the pole. to be a mountain, the highest feature on Mars.