EDUCATOR’S PAGE
Other minerals discovered on Mars, like goethite and arosite, imply alteration in the presence of water[13]. Goethite is a hydrous form of iron oxide and arosite is a hydrous potassium iron sulfate. Adding to the mounting evidence of a watery past for Mars are laminated mud- stones on the floor of Gale Crater[14]. Less surprising, crossbedding in sandstones is documented near Mount Sharp[15] and the 4000 km long, 7 km deep, Valles Marineris, exhibits layers of rock much like the Grand Canyon on Earth. Both Gale Crater and Mount Sharp are areas examined by the Curiosity rover in its nearly 13 kilometer trek across the sur- face of Mars since landing in 2012.
From a broader perspective, Mars exhibits a crustal dichotomy, with the southern hemisphere having a higher elevation and older surface (i.e., more craters) than the northern hemisphere. Unlike Earth, Mars shows no sign of ever having experienced large scale plate tectonics. The presence of truly enor- mous shield volcanoes, like Olympus Mons, is evidence for a stationary crust, because the volcanoes continued to build in a single location (unlike the chain of Hawaiian Islands on Earth). Some of the youngest lava flows on Mars appear to be within Elysium Planitia, a large volcanic region, at Athabasca Valles.[16]. Whether Mars is volcanically active, dead, or dor- mant, remains to be determined.
Not all data about Mars has been collected remotely. In addition to the data collected at Mars, several meteor- ites have traveled from the planet and landed on Earth (probably blasted to escape velocities by impacts on Mars). Over 60,000 meteorites have been found on Earth, and ust over 120 are from Mars[17]. Included among these are the shergottites, nakhlites, and chassignites (SNCs). Basaltic meteorites provide direct evidence from Mars of volcanism as early as 180 million years ago [18].
Summary
Mars has been the subect of intense scientific investigation, driven largely by its proximity and similarity to Earth, but also because of the presence of water and potential for life. We continue to learn more about this enigmatic planet through the on-going activities of the Curiosity rover and the MAVEN orbiter. As humans ponder the possibility of set- tling on other planetary bodies in our solar system, Mars is clearly a candidate at the top of the list as NASA explores the
potential for sending manned missions to the Red Planet.
Featured resource
This issue’s featured resource is the Mars Exploration web page at http://
mars.nasa.gov/ suitable for children and adults, the website features direct links to the latest updates and images from Mars. A menu bar on the left side of the main page provides links to all of the current NASA missions active on Mars. Also at the main page is a link to Mars Quick Facts, which takes you to a colorful set of pictographs with general informa- tion about the planet as compared to the Earth. A series of dropdown menu bars at the top of the page enable you to search out and access various other links per- taining to programs, news, multimedia, and more.
References
1. NASA. (n.d.). Mars exploration: Historical log. Retrieved from
http://mars.nasa.gov/program- missions/missions/log/
2. Hille, K. (2015, July 30). MAVEN mission overview. Retrieved from
http://www.nasa.gov/mission_ pages/maven/overview/
index.html
3. Garner, R. (2015, November 10). Visualizing Mars’ atmosphere loss. Retrieved from
http://www.nasa. gov/image-feature/goddard/visu- alizing-mars-atmosphere-loss
4. Munsell, K. (2016, March 9). InSight. Retrieved from
http://insight.jpl.
nasa.gov/home.cfm
5. Williams, D. R. (2016, April 19). Mars fact sheet. Retrieved from
http://nssdc.gsfc.nasa.gov/plan- etary/factsheet/
marsfact.html
6. Erickson, K. (2011, September 20). Planet gobbling dust storms. Retrieved from http://science.
nasa.gov/science-news/science-at- nasa/2001/ast16jul_1/
7. Erickson, K. (2011, September 20). The devils of Mars. Retrieved from
http://science.nasa.gov/science- news/science-at-nasa/2005/14jul_ dustdevils/
8. NASA administrator. (2013, July 28). South polar winter snow depos- its. Retrieved from http://www.
nasa.gov/mission_pages/MRO/ multimedia/
pia16138.html#. V1iKQ74XHa4
9. Connolly, J. & Lloyd, C. (2006, July 10). Why do we want to study and travel to Mars? Retrieved from
https://education.jsc.nasa.gov/ explorers/
p8.html
10. NASA Administrator. (2013, July 28). NASA helps see buried Mars flood channels in 3-D. Retrieved from
http://www.nasa.gov/mission_ pages/MRO/news/mro20130307. html#.V1iOA74XHa4
11. Brown, D., Cantillo, L, & Webster, G. (2015, September 28). NASA confirms evidence that liquid water flows on today’s Mars. Retrieved from
https://www.nasa.gov/ press-release/nasa-confirms-evi- dence-that-liquid-water-flows-on- today-s-mars
12. NASA. (n.d.). Mars exploration: Chemistry & mineralogy X-ray dif- fraction. Retrieved from http://
mars.nasa.gov/msl/mission/ instruments/spectrometers/che- min/
13. NASA. (n.d.). Mars exploration: Characterize the geology of Mars. Retrieved from
http://mars.nasa. gov/mer/science/goal3-results. html
14. Greicius, T. (2015, October 8). Secrets of ‘hidden valley’ on Mars. Retrieved from
https://www.nasa. gov/image-feature/jpl/pia19840/ secrets-of-hidden-valley-on-mars
15. Greicius, T. (2015, September 11). Vista from Curiosity shows crossbed- ded Martian sandstone. Retrieved from
https://www.nasa.gov/ image-feature/jpl/msl/pia19818/ vista-from-curiosity-shows-cross- bedded-martian-sandstone
16. Whatmore, R. (201, January 11). Turbulent lava flow in Mars’ Athabasca Valles. Retrieved from
http://www.nasa.gov/mission_ pages/MRO/multimedia/mro-
20100111.html
17. Baalke, R. (n.d.). Mars meteorites. Retrieved from
http://www2.jpl.
nasa.gov/snc/
18. Lunar and Planetary Institute. (2016). Shaping the planets: Volcanism. Retrieved from http://
www.lpi.usra.edu/education/ explore/shaping_the_planets/vol-
canism.shtml
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