Posts Tagged ‘Mars’

Methane on Mars: Extremophiles or Geothermal ?

Monday, February 9th, 2009 by Evan Finnes

Could the detection of methane on Mars be an indication of microbial life, or is a geologic process causing this chemical anomaly?    Prior to 2003, no methane was observed in the Martian atmosphere, beginning on 2003 methane was detected using three ground-based infrared spectrometers.  This Methane was then observed over a three year period (seven Earth years).  The largest plumes were observed during the summer months, the largest contained approximately 19000 metric tons of methane.

The Martian atmosphere is composed of 95% carbon dioxide, 2.7% nitrogen, .07% carbon monoxide, .13% oxygen, 1.6% argon, and trace amounts of water vapor.   Small amounts of methane may be produced due to atmospheric processes but would be relatively short lived due to the ionization of the compound, caused by UV radiation.  Therefore any large amounts of methane present in the atmosphere would have to be the result of the release of a subsurface reservoir.  The origin of such methane reservoirs is unknown, but could be due to biologic or natural processes. 

If 90% of Earth’s methane is produced by life forms, could the methane on Mars also be produced biologically?  Extremophiles could live deep below the surface of Mars where they could use hydrogen as an energy source; this energy could be produced when water exposed to radiation is dissociated into H2 and oxygen.  This reaction also reduces carbon dioxide to methane, which could accumulate in subsurface reservoir s.  If these reservoirs are connected to the surface along faults or fractures, seasonal variations could result in the opening of such cracks which could lead to the release of any methane accumulations.  Extremophiles of this type can be found 3 km below the Witwatersrand Basin of South Africa. 

Another possible source of the methane deposits could be of geologic origin.  Such processes could include the production of magma, or the serpentinization of basalt.  Either of these possibilities could also result in the buildup of subsurface methane deposits.  Much like the extremophile scenario, these deposits could also be released due to the temperature variations that occur with seasonal changes.

The methane appears in highest concentrations at three regions:  Arabia Terra, Nili Fossae, and the South-East corner of Syrtis Major.  The Mars Reconnaissance Orbiter and Mars Express observed that the outcrops in the Nili Fossae region are rich in hydrated minerals.  This suggests that this area resides above a magma chamber.  The largest plume was observed over shield volcano located between Sytris Major and Nili Fossae.  This further suggests that the area is above a magma chamber, and that the production of magma, or the serpentinization of basalt is responsible for the release of the methane plumes, and are probably not the result of the presents of Martian extremophiles.        

[Slashdot] [Digg] [Reddit] [] [Facebook] [Technorati] [Google] [StumbleUpon]

Large Deposits of Water-Ice Found on Mars

Monday, November 24th, 2008 by Evan Finnes

On November 20th, 2008, NASA confirmed that the Mars Reconnaissance Orbiter has discovered ancient glaciers of water-ice preserved under a layer or dust and rock. These subsurface glaciers are located at altitudes much lower than any previously discovered layers of ice, and also contain more water-ice than any other region on Mars, including the poles.

These glaciers were discovered underneath a formation that had been puzzling geologists for years. These formations are known as “aprons” because of the way they gently slope upwards. The glaciers were discovered after ground penetrating radars were pointed at these “aprons” because the radio waves were reflected without a significant loss of energy shortly after penetrating the surface. The radio waves that are not reflected travel through these formations with an apparent velocity, which is consistent with the composition of water-ice.

Hundreds of these apron-like features are located in latitude bands between 35 and 60 degrees on either side of the Martian equator. They are also commonly located beneath cliffs and are typically tens of kilometers long, and may be the remnants of a giant ice sheet, which may have at one time engulfed these mid-altitude regions. Many scientists believe that Mars was once tilted in such a fashion that the poles pointed toward the Sun, leaving the mid-latitude regions in a much cooler climate. This discovery offers proof to this hypothesis.

Studying these ice-sheets could help us understand processes that effect climate change, which is a poorly understood phenomenon, here on Earth. Our last glacial Maximum occurred about 20,000 years ago, when much of the North American and Eurasian continents were covered in an ice sheet over 3 kilometers thick. There are many factors which are thought to cause the onset of an ice age, such as: changes in the atmosphere, tectonic geography, variation in the Earth’s orbit, and variations in solar energy. The changes in the atmosphere which effect the onset of glaciers is not well understood, although, there is some proof that CO2 levels shrink during the onset of an ice age, and increase during interglacial periods. The effects of increased CO2 on the climate have long been a subject of great debate. Tectonic geography affects the onset of ice ages by arranging the continents in such a way that they prevent the flow of warm water from the equator to the poles; this allows the formation of ice sheets. These ice-sheets increase the planets albedo, which decreases the amount of solar radiation, which is absorbed. This decrease in absorbed energy allows the ice sheets to expand. There are three known configurations which block or reduce this flow of warm water–two of which exist today. A continent sits on top of a pole, such as Antarctica. Or a polar sea, such as the Arctic Ocean, is nearly land-locked. The third configuration consists of a single mass continent which covers much of the equator. Such a mass continent existed between 850 and 635 million years ago during the Cryogenian period, and was called Rodinia. Variations in the Earth’s orbit, called Milankovitch cycles, suggests that major ice ages occur every 100,000 years due to periodic changes in Earth’s eccentricity, axial tilt, and orbital periods; however, how these variations effect the climate are not well understood.

The discovery of these large volumes of water-ice on Mars will be very important to the future colonization, and manned missions to mars. This ice will serve as drinking water, and as a source of energy, which will be used in hydrogen fueled vehicles. This will defiantly reduce costs for such future missions because fewer supplies will have to be shipped to the red planet.

On Earth, such buried glaciers in Antarctica preserve traces of ancient organisms. So these Martian glaciers might also serve as a place to look for fossil evidence of past life on Mars. In addition to fossil life, localized heating due to volcanism may have melted some ice, which could provide an environment for microorganisms to evolve.

The discovery of subsurface glaciers on Mars will help us understand the processes which evoke climate change on Earth, provide a place to gather food and fuel for future missions to Mars, and could be one of the best places to look for signs of ancient organisms. Indeed, these will be places which will be thoroughly explored by rovers, Landers, and eventually, by mankind.

[Slashdot] [Digg] [Reddit] [] [Facebook] [Technorati] [Google] [StumbleUpon]

The Final Sols of the Phoenix Lander

Thursday, October 9th, 2008 by Evan Finnes

After two mission extensions, the Phoenix Lander has been on the Martian surface for five months. But with an approaching winter, the Lander is already beginning to lose power, as it must now sit in five hours of freezing darkness each day. The rover will slowly lose power until the end of October when it will no longer be able to use its robotic arm. Even though its days are numbered the Phoenix Lander is still making discoveries.

For the first time in Martian history, Phoenix observed Martian snowfall. The snow observed at an altitude of about 4km above the Lander, and it appears to have vaporized before reaching the surface. The Lander has also discovered several minerals that, on Earth, would typically form in the presence of water.

Potentially, the most exciting mineral discovered is Calcium Carbonate, (CaCO3). Calcium Carbonate is the main component of chalk, which forms in deep marine conditions from the gradual accumulation of calcite plates called coccoliths, which are shed from microorganisms called cocolithosphores. The discovery was made by the combined data of two instruments onboard the Phoenix Lander. The Thermal and Evolved Gas Analyzer,(TEGA), discovered that Carbon Dioxide was released from soil samples when exposed to high temperatures. The temperature at which the CO2 was released is a temperature which is known to breakdown CaCO3 into CO2. The Microscopy, Electrochemistry and Conductivity Analyzer, (MECA), found concentration of (Ca) in the soil; this confirms the presence of CaCO3 in the soil. The presence of Calcium Carbonate does not immediately imply that chalk or microorganisms have been discovered, future tests will have to be done to determine if the CaCO3 was formed due to ancient marine life.

Both MECA and TEGA discovered have smooth-faced layered particles which resemble clay. Clay minerals have a crystal structure which allows them to store water between Silicon and Oxygen Bonds. These bonds are relatively weak, this allows the bonds to expand and contrast depending on the water content of the environment they are in. These weak bonds also break easily along the bonding planes which give them the smooth and layered surfaces which were observed by the Lander.

Currently, Phoenix is beginning to analyze the soil found in a region called “Galloping Hessian”. This area is being explored because of its high concentration of salts. On Earth Salts are also commonly found in dried up sea beds. As the darkness and the cold settles in over the Lander its days of discovery are nearing an end. Because of the extreme conditions of the Martian winter, which loom in the Landers very near future, scientists do not think that they will be able to resurrect it when spring finally returns.

[Slashdot] [Digg] [Reddit] [] [Facebook] [Technorati] [Google] [StumbleUpon]

Mars Atmosphere and Volatile EvolutioN

Monday, September 22nd, 2008 by Evan Finnes

NASA has chosen a new mission in the Mars Exploration Program to study the Martian atmosphere. The purpose of the $485 million MAVEN mission, (Mars Atmosphere and Volatile EvolutioN), is to study the Martian Atmosphere, climate history, and potential habitability. This mission is intended to take the most detailed measurements ever recorded in the Martian atmosphere.

After the launch in 2013, MAVEN will enter an elliptical orbit from 90 to 3870 miles above the Martian surface where it will take measurements for an entire Earth year. Maven will also descend to an altitude of 80 miles above the surface where it will take detailed measurements of the upper atmosphere. After the mission is complete MAVEN will be used as a communications satellite for future rovers and landers.

The Martian atmosphere is relatively thin, with pressures ranging from .03 kPa to 1.155 kPa, and an average sea-level pressure of about .6 kPa (nearly 170 times less than that of Earth). Even though the atmosphere on Mars is 4 km taller than Earths, its Mass is nearly 206 times less than Earths. The atmosphere is composed of 95% CO2, 3% N, 1.6% Ar, with trace amounts of O2, H2O, and CH4. The atmosphere has been divided into 4 subdivisions: lower atmosphere, middle atmosphere, Upper atmosphere, and exosphere. The lower atmosphere is region that is warmed from airborne dust particles. The middle atmosphere is distinguished only by a jet stream. The upper atmosphere is characterized by very high temperatures, and the atmospheric gasses are stripped apart by the sun. The exosphere, like on Earth, is the boundary-less region where the atmosphere slowly tappers out into space.

Because Mars has the only surface observable from Earth, its climate has been studied since the 17th century. The first up-close climate observations were made in the 60’s by the Mariner missions and the Viking missions of the 70’s. Today the Mars Global Surveyor keeps up where they left off. We know that the Martian climate has some similarities with the Earth, such as changing seasons, ice-ages, and even a sublimating south-pole which could indicate a warming climate. Unlike Earth, Mars lacks water and has a low ability to resist temperature change during a full heating/cooling cycle.

Recent Missions such as the rovers, Spirit and Opportunity, have shown that large amounts of water most likely existed on the Martian surface at one time. So with any luck, MAVEN will be able to provide some insight into where this water went, and what happened to a Martian atmosphere that was once able to support water and perhaps life. Even more importantly, MAVEN will help us understand the evolution and the eventual fate of our own atmosphere.

[Slashdot] [Digg] [Reddit] [] [Facebook] [Technorati] [Google] [StumbleUpon]

Our Undiscovered Universe Blog is proudly powered by WordPress
Entries (RSS) and Comments (RSS).