Channels on Martian Surface Still a Mystery

by Sequoyah High School 2012 1st period honors physics students (students are listed by name at the end of the article).

Since humans first looked up and pondered the heavens, mankind has contemplated the possibility of life beyond Earth. From Kepler’s 1634 science fiction account of travelling to the moon in his book The Dream to H. G. Wells’ The War of the Worlds, and even popular blockbusters such as Mars Attacks and Men in Black, man’s fascination with space and the possibility of the life-forms that dwell there is well documented. NASA’s Odyssey Program now allows humankind to search beyond the limits of Earth’s atmosphere and beyond Earth’s moon to discover a planet that exhibits similarities with Earth.  One of those similarities is the presence of water, “a necessary condition for the emergence of life” (NASA Astrobiology Institute, 2007).  Since water is a necessary condition for life, the Sequoyah High School Honors Physics students sought to obtain evidence to determine the presence of water on the Martian surface. The research question was, “Among channels existing on the surface of Mars, how prevalent are those exhibiting evidence of origins in fluvial systems rather than volcanic flow?”

Channels provide evidence of flowing liquid which could possibly have been water, and the existence of water indicates that certain life-forms could be possible. Also, the presence of water on Mars provides a similarity with Earth and allows researchers to better understand the relationship between the history of Mars and the future of Earth. The hypothesis for this research is, Images of channels on the Martian surface and the examination of characteristics of those channels will indicate that some were created by water flow.

Background

Mars is a frozen desert, filled with dry dust, and apparently void of life, so it is surprising that Mars and Earth share some common characteristics.  Mars is very similar to Earth in that it has an atmosphere, albeit much less dense than Earth’s, and this atmosphere produces clouds and wind (Miles and Peters, 2008).  Also, Mars and Earth possess polar ice caps; however, the NASA probe Mariner 7 revealed that the Martian ice caps are carbon dioxide (dry ice) instead of water (Watt, 2002, pg. 6).  NASA researchers postulate that water ice is buried below the dry ice but efforts to prove this point have not been successful (Watt, 2002, pg. 15).  Recent evidence does support that flowing water did exist on Mars sometime during its history, and water in the form of ice may still exist today (Arizona State University Mars Space Flight Facility, n.d.).

Characteristics of Mars’ surface that would indicate past or present existence of water are “small islands, secondary channels that branch off and rejoin the main one and eroded bars on the insides of the curves of the channels” (Zubritsky, 2010). The history of the channels is still unclear, but the widely held belief is that water carved some of the channels present on Mars’ surface. Additionally, studies suggest that lava systems could potentially form the same channels. Scientists, under a team lead by Jacob Bleacher, examined lava flows on Earth and determined that those flows could also produce terraced walls; however, the team said their findings did not rule out the possibility for the existence of water on the surface (Zubritsky, 2010).

Indeed, chemical analysis goes against Bleacher’s hypothesis on the history of the channels on Mars. When the Phoenix Mars Lander arrived on Mars, it was able to collect samples of soil to analyze before the lander stopped working. Mars’ atmosphere is thinner than Earth’s, so carbon is lost to space. Scientists would expect that the atmosphere of Mars would be heavily depleted of Carbon-12 and made primarily of heavier Carbon-13; however, the analysis done by the Phoenix showed large amounts of Carbon-12, suggesting the carbon was replenished recently. An even more surprising finding was the presence of oxygen isotopes in the Martian atmosphere. Scientists cite the presence of oxygen as evidence of liquid water on Mars in recent history because the carbon dioxide reacted with oxygen (Webster & Jeffs, 2010).

Certain images of Mars indicate that water or other liquids once flowed on the surface of Mars creating channels and gullies.  The channels are characterized by a branching pattern, referred to as a dendritic pattern, associated with water flowing.  These channel systems have been found in the Echus and Melas Chasma regions of Mars. Scientists also speculate that snow or rainfall could have contributed to the flowing water (Arizona State University Mars Space Flight Facility, n.d.). The fact that these channels form meandering patterns in much the same fashion as water channels found on Earth suggests that similar factors are causing these channels to form on both planets. Meandering fluvial systems on Earth are often the result of vegetation creating a trap for sediment to discourage erosion which in turn causes the channels to snake throughout the landscape. Although Mars lacks this type of vegetation, scientists believe that the clay sediment found on Mars, in addition to microbial crusts found on the surface, provides the same cohesion required to prevent erosion and make the channels curve. With this evidence in mind, the theory that water once flowed through the channels is still sound even without the specific circumstances outlined by the water systems on Earth. Scientists speculate that “large meteor impact or volcanic eruption” could have “melted ice and created a wet micro-climate for a short period of time in the recent past” (Schirber, 2009). The occurrence of large impact craters could have contributed to flooding that resulted in the channel formation seen on Mars today. “The force of the impact melted the permafrost . . . . and caused the resulting water to flow violently away from the crater” (Watt, 2002, pg. 17-18).

When evaluating images of channels, one must discern the differences between channels formed by lava flow and those formed by the flow of water.  Also, certain characteristics of channels resulting from water flow give clues to the amount of water present.  The channel walls, floors, and tributaries may be analyzed to determine water volume (Watt, 2002, pg. 18).

Figure 1, THEMIS Image No. V11030007 provides insight into the differences between channels formed by lava flow and those formed by water.  This figure is a THEMIS image of a section of the channel system Hebrus Vallis. The perpendicular flow of channels apparent in this image is not associated with fluvial systems and is more indicative of a channel system formed by flowing lava.  Indeed, Hebrus Vallis originates close to the base of the Elysium volcanic complex and was likely formed by volcanic activity (Christensen, 2004, Image No. V11030007). Lava channels are also characterized by rafting where hard pieces of crust harden and create a damming effect, thus causing the lava to sharply change its flowing pattern and in many cases create perpendicular channels (Swann, 2012), and generally, multiple lava flows occur in one image (Mars Student Imaging Program, 2007).

A channel indicating water flow is provided in Figure 2, THEMIS Image No. V03701003, a section of the Minio Vallis Channel (Christensen, 2004, Image No.  V03701003). Channels formed by water flow exhibit a meandering shape. Typically, these patterns are formed by water flow responding to resistance to erosion on the surface, whereas lava simply cuts through and branches off abruptly. Conversely, water creates main channels that have secondary channels branching off and rejoining the main one.

Methods

Data was collected via the Thermal Emission Imaging System (THEMIS), a camera onboard Mars Odyssey, capable of producing images with both visible and infrared light.  Utilizing visible imaging, the instrument is capable of “20-meter resolution measurements of the surface,” and infrared data may be used to enhance the visual images (Watt, 2002, pg. 42). The image data was collected via real-time streaming from the current orbital location of Mars Odyssey.  Two images were received from the THEMIS camera; however, only one of the images was able to be analyzed due to dust distortion of the other picture.

The research focused on the presence of channels and specifically whether those channels were formed by lava or water flow. Specific criteria were applied to determine the cause of formation of the channels in the image collected and surrounding area. These criteria were:

Features indicating past water flow

Primary Criteria

  • Dendritic Patterns
  • Meandering patterns in much the same fashion as water channels found on Earth
  • Smooth transitions from channel bed to surrounding area

Secondary Criteria

  • Secondary channels that branch off and rejoin the main one
  • Streamlined islands

Features indicating past lava flow

Primary Criteria

  • Lava flows 90o perpendicular out of the channels
  • Multiple lava flows in one image.
  • Abrupt bump in the transition from channel bed to surrounding area

Secondary criteria

  • Abrupt changes in channel direction

The transition from channel bed to surrounding area was surmised using JMARS to develop elevation views of the identified channels. An example of a smooth transition indicative of a water channel is provided to the left as a standard for comparison.  This graph was developed using the JMARS MOLA 128ppd Elevation feature for a channel occurring at 337.75E, 8.625 N. Likewise, the figure below, developed using the same feature illustrates a typical transition for a lava channel.

Our target image was qualitatively analyzed and significant features such as the characteristics of the channels that support its formation by water or lava were labeled on the image (See THEMIS target image in Data). The area surrounding the target image was analyzed qualitatively in a similar fashion and MOLA elevation views were generated to evaluate the channel bed transitions. The JMARS images and MOLA elevation views are provided in the Data section. The information and data collected were organized according to the following table:

Image   ID No.

Lat.   (N)

Long.   (E)

Channels   (Y/N)

Specific   observations of feature

Formed   by Lava or Water?

           
           

Data

We collected 2 THEMIS images but were only able to use one of them due to dust distortion of one of the images. The location of the Martian surface depicted in the THEMIS target image is shown on the following Google Mars image (Google Mars, 2012):

The observations resulting from the qualitative analysis are labeled on the THEMIS image shown on the right.

The table below the image delineates the features that were observed in the surrounding areas of our target image of Martian surface.

      Table 1: Observations
 
Image ID No. Lat. (N) Long. (E) Channels (Y/N) Specific observations of feature Formed by lava or water?
V46057015 18.662 184.154 Y Streamlined islands,
Meandering patterns
Water
JMARS 11.375 181.25 Y Streamlined islands,
Meandering patterns,
1 perpendicular channel
Indeterminate.First two observations indicate water;
3rd indicates lava.
JMARS 18.125 185 Y Streamlined islands,
Meandering patterns
Water
JMARS 32.339 165.005 Y Meandering patterns.
Abrupt transition across
channel bed
Indeterminate; displays characteristics of both.
JMARS 18.586 184.194 Y Meandering patterns.
Smooth transition across
channel bed.
Secondary channels branch off
and re-join main channel.
Streamlined islands.
Water
JMARS 12.75 182.625 Y Dendritic patterns.
Secondary channels branch off
and re-join main channel.
Streamlined islands.
Abrupt transition across
channel bed.
Abrupt changes
in channel direction 
Indeterminate; displays characteristics of both.
JMARS 11.590 N 180.746 Y Secondary channels branch off
and re-join main channel.
Streamlined islands.
Abrupt transition across
channel bed.
Indeterminate; displays characteristics of both.

Table 2: Sample images and corresponding elevation views

Location JMARS image MOLA Elevation View
165.005 E, 32.339 N    
184.194 E, 18.586 N    
182.625 E, 12.75 N    
180.746 E, 11.590 N    
183.834 E, 16.303 N    

Discusson

As shown in Table 1 of the Data section, the THEMIS image displays characteristics that provide evidence of the past existence of fluvial systems.  These characteristics include very wide, shallow channels, streamlined islands, and meandering patterns; however, features in the surrounding area indicate evidence of lava systems.  One of those features is rafting, a condition associated with lava flow that is typically indicated by 90o bending of the channel (indicated in JMARS 11.375N and 181.25E). Our observation of rafting indicates that the characteristics of this area do not support water formation. All other surrounding areas that we analyzed were either indeterminate or indicated water formation. Out of the 7 areas analyzed, 4 areas were indeterminate with respect to cause of channel formation. While there is evidence supporting fluvial systems in our target THEMIS image, there is not enough evidence from the surrounding area for us to conclude our channel was created by water flow.

Based on images of the area surrounding our THEMIS image and the MOLA elevation maps, we have decided that the data is inconclusive.  Features found in the images and elevation maps contained characteristics of both water and lava. While most of the elevation maps leaned toward lava, there were features that were characteristic of water in the JMARS images. Since the area displays evidence of both fluvial and lava systems, it is possible that a volcanic eruption could have melted ice and created a system of water and lava as described by Schirber (2009), but future work is needed before this conclusion can be drawn.

When collecting our data, errors may have occurred due to a few factors. Inaccuracies could have occurred because of the inexperience of the student researchers.   Being in high school, the researchers have not had much exposure to Mars and its features, and this was our first experience interpreting satellite images and using JMARS.  Also, at the time the images were taken, there was a dust storm on Mars that prevented one of our images from being analyzed. Our data could have been misinterpreted because of the student researchers’ bias towards water systems.  Our question addresses the prevalence of fluvial systems, so there is a possibility that we were leaning towards fluvial systems over lava.

Conclusion

This project allowed the Sequoyah High School Honors Physics students to investigate evidence to address mankind’s persistent curiosity about the potential for life on Mars.  Specifically, the research effort focused on the presence of water since water is a necessary condition for life. Since the presence of channels provides evidence concerning the existence of water, the research was driven by the question, “Among channels existing on the surface of Mars, how prevalent are those exhibiting evidence of origins in fluvial systems rather than volcanic flow?”  The hypothesis developed was: Images of channels on the Martian surface and the examination of characteristics of those channels will indicate that some were created by water flow. Based on the evidence found in our target image and a thorough examination of the surrounding area, we are unable to conclude the exact method of formation of the channels that we reviewed because they displayed features of both water and lava systems.

The research question was developed with the goal of gaining an understanding of the relationship between life-sustaining water on Earth and the presence of water on Mars. Understanding this relationship offers insight into the future of our planet based on the history of Mars and the fate of Martian fluvial systems. Unfortunately, our data were inconclusive and more work is necessary to accurately determine the cause of channel formation in our target area of the Martian surface. If we expanded our surrounding area, we might find evidence of volcanic systems or impact craters that would provide more insight into the history of our area. Additionally, investigating the history of weather phenomena in our area could provide more evidence to assist in establishing more definitively the origins of the channel systems in our target area.

Acknowledgements

The Sequoyah High School Honors Physics class would like to acknowledge and thank our teacher Mrs. Geddes for providing mentorship and guidance for this project. We would also like to thank Jessica Swann of the Mars Space Flight Facility for her dedication to our efforts.

The students of the Sequoyah High School 2012 1st period honors physics are: Michelle Blankinship, Deanna Cape, Megan Cargin, Cody Copeland,  Tori Falco, Bobby Flanagan, Joe Garcia, Christina Herd, Natalie Hopkins, Stephen Ibar, Emily Kidd, Lauren LoPiccolo, Megan Pace, Connor Reeder, James Rogers, Priscilla Rojas, Megan Simms, Anna Singh, Haley Smith, Ayana Thomas, Yulian Vieta, Kristin White, and Derek Willingham.

References

Arizona State University Mars Space Flight Facility. (n.d.). Mars has more channels than previously thought. Retrieved April 3, 2012, from Mars Odyssey THEMIS: http://themis.asu.edu/node/5399

Christensen, P.R., N.S. Gorelick, G.L. Mehall, and K.C. Murray. THEMIS Public Data Releases, Planetary Data System node, Arizona State University, <http://marsed.asu.edu/files/MSIPResourceManualv200.pdf&gt;.

Google Mars. (2012). 18.622 N and 184.154 E Retreived May 21, 2012.

Mars Student Imaging Program. (2007, May 31). Feature ID Chart.  Retrieved April 3, 2012, from Welcome to the Mars Student Imaging Program: http://marsed.mars.asu.edu/files/msip_resources/FeatureIDCharts.pdf

Miles, K. and Peters, C. (2008). The Martian Atmosphere. Retrieved April 3 2012, 2012, from Starry Skies: http://starryskies.com/solar_system/mars/martian_atmosphere.html

NASA Astrobiology Institute. (2007, December 21). Is Water Necessary for Life? Retrieved April 3, 2012, from Astrobiology: Life in the Universe: http://astrobiology.nasa.gov/nai/seminars/detail/161.

Schirber, M. (2009, December 10). The meandering channels of mars. Retrieved April 12, 2012, from Astrobiology Magazine: http://www.astrobio.net/exclusive/3337/the-meandering-channels-of-mars.

Swann, J. (2012, April 18), Education and Technology Specialist with Mars Space Flight Facility, in a teleconference with Sequoyah High School Honors Physics Students.

Watt, K. (2002). Mars Student Imaging Project: Resource Manuel. Retrieved June 29, 2006, (April 3, 2012) from Arizona State University, Mars Student Imaging Project Web site: http://msip.asu.edu/curriculum.html.

Webster, G. &. (2010, September 9). NASA Data Shed New Light About Water and Volcanoes on Mars. Retrieved April 12, 2012, from http://www.nasa.gov: http://www.nasa.gov/mission_pages/phoenix/news/phx20100909.html.

Zubritsky, E. (2010, March 4). Lava likely made river-like channel on Mars. Retrieved April 12, 2012, from http://www.nasa.gov: http://www.nasa.gov/topics/solarsystem/features/mars-lava-channels.html.

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