![This side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from the Martian surface by NASA's Curiosity rover. These images, made from data obtained by Curiosity's Chemistry and Mineralogy instrument (CheMin), show the patterns obtained from a drift of windblown dust and sand called "Rocknest" and from a powdered rock sample drilled from the "John Klein" bedrock.The presence of abundant clay minerals in the John Klein drill powder and the lack of abundant salt suggest a fresh water environment. The presence of calcium sulfates rather than magnesium or iron sulfates (as found at Meridiani Planum by NASA's Mars Exploration Rover Opportunity) suggests a neutral to mildly alkaline pH environment. The Rocknest sand shadow mineralogy suggests a dry, aeolian environment with low water activity. The John Klein mineralogy suggests a lacustrine environment with high water activity.As seen on the left, the Rocknest data reveal abundant plagioclase feldspar, pyroxene and olivine minerals. The data also indicate reveal small amounts of magnetite and anhydrite. In addition, the Rocknest sample contains 25 to 35 percent amorphous material.X-ray diffraction analysis of the John Klein drill powder reveals abundant phyllosilicate, plagioclase feldspar, pyroxene, magnetite and olivine. Alternatively, the clay minerals could have been transported by water from sources higher up the sediment fan to form the John Klein mineral assemblage. The region of the pattern indicating the phyllosilicates is labeled in the annotated version of this image. The data also show minor amounts of anhydrite and bassanite. The John Klein sample also contains about 20 percent amorphous material.](http://cdn2-b.examiner.com/sites/default/files/styles/thumbnail/hash/4d/8d/4d8da0af79d795a4ddb71096345a6583.jpg?itok=Uv1UhcPH "This side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from the Martian surface by NASA's Curiosity rover. These images, made from data obtained by Curiosity's Chemistry and Mineralogy instrument (CheMin), show the patterns obtained from a drift of windblown dust and sand called "Rocknest" and from a powdered rock sample drilled from the "John Klein" bedrock.The presence of abundant clay minerals in the John Klein drill powder and the lack of abundant salt suggest a fresh water environment. The presence of calcium sulfates rather than magnesium or iron sulfates (as found at Meridiani Planum by NASA's Mars Exploration Rover Opportunity) suggests a neutral to mildly alkaline pH environment. The Rocknest sand shadow mineralogy suggests a dry, aeolian environment with low water activity. The John Klein mineralogy suggests a lacustrine environment with high water activity.As seen on the left, the Rocknest data reveal abundant plagioclase feldspar, pyroxene and olivine minerals. The data also indicate reveal small amounts of magnetite and anhydrite. In addition, the Rocknest sample contains 25 to 35 percent amorphous material.X-ray diffraction analysis of the John Klein drill powder reveals abundant phyllosilicate, plagioclase feldspar, pyroxene, magnetite and olivine. Alternatively, the clay minerals could have been transported by water from sources higher up the sediment fan to form the John Klein mineral assemblage. The region of the pattern indicating the phyllosilicates is labeled in the annotated version of this image. The data also show minor amounts of anhydrite and bassanite. The John Klein sample also contains about 20 percent amorphous material."){kind=small}
![This false-color map shows the area within Gale Crater on Mars, where NASA's Curiosity rover landed on Aug. 5, 2012 PDT (Aug. 6, 2012 EDT) and the location where Curiosity collected its first drilled sample at the "John Klein" rock. The image merges topographic data with thermal inertia data that record the ability of the surface to hold onto heat. Red indicates a surface material that retains its heat longer into the evening than other areas, suggesting differences relative to its surroundings. Curiosity crossed the boundary from lower thermal inertia values to higher values on Dec. 8, 2012 while driving down into an area known as "Yellowknife Bay". The black oval indicates the targeted landing area for the rover, known as the "landing ellipse," and the black cross shows where the rover actually touched down at what has since been named the Bradbury Landing site. The blue circle indicates where the John Klein drill site is within the Yellowknife Bay area.An alluvial fan, or fan-shaped deposit where debris spread out downslope, has been highlighted in lighter colors for better viewing. On Earth, alluvial fans often are formed by water flowing downslope. The John Klein outcrop is part of a geologic layer, known as "Sheepbed," which is a mudstone with abundant evidence for ancient aqueous processes. It seems likely that sediments were transported downhill from the eroding crater rim and became part of alluvial fan systems. The materials then flowed out where water and sediments accumulated to form a habitable environment represented by the Sheepbed mudstone.This image was obtained by the Thermal Emission Imaging System on NASA's Odyssey orbiter.](http://cdn2-b.examiner.com/sites/default/files/styles/thumbnail/hash/81/84/8184f5495dcfaf713df337c8b179d275.jpg?itok=_ypzkKGG "This false-color map shows the area within Gale Crater on Mars, where NASA's Curiosity rover landed on Aug. 5, 2012 PDT (Aug. 6, 2012 EDT) and the location where Curiosity collected its first drilled sample at the "John Klein" rock. The image merges topographic data with thermal inertia data that record the ability of the surface to hold onto heat. Red indicates a surface material that retains its heat longer into the evening than other areas, suggesting differences relative to its surroundings. Curiosity crossed the boundary from lower thermal inertia values to higher values on Dec. 8, 2012 while driving down into an area known as "Yellowknife Bay". The black oval indicates the targeted landing area for the rover, known as the "landing ellipse," and the black cross shows where the rover actually touched down at what has since been named the Bradbury Landing site. The blue circle indicates where the John Klein drill site is within the Yellowknife Bay area.An alluvial fan, or fan-shaped deposit where debris spread out downslope, has been highlighted in lighter colors for better viewing. On Earth, alluvial fans often are formed by water flowing downslope. The John Klein outcrop is part of a geologic layer, known as "Sheepbed," which is a mudstone with abundant evidence for ancient aqueous processes. It seems likely that sediments were transported downhill from the eroding crater rim and became part of alluvial fan systems. The materials then flowed out where water and sediments accumulated to form a habitable environment represented by the Sheepbed mudstone.This image was obtained by the Thermal Emission Imaging System on NASA's Odyssey orbiter."){kind=small}
![These images compare rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars. On the left is "Wopmay" rock, in Endurance Crater, Meridiani Planum, as studied by the Opportunity rover. On the right are the rocks of the "Sheepbed" unit in Yellowknife Bay, in Gale Crater, as seen by Curiosity.The "Wopmay" rock is formed from sandstone, which scientists think were formed partly in the presence of water. They also think the concretions were formed in the presence of water. The "Wopmay" rock records an ancient aqueous environment that was likely too acidic, too nutrient-poor, and too salty for microorganisms to survive.The "Sheepbed" rock, on the other hand, records an ancient aqueous environment that was habitable. While being formed much like the "Wopmay" rock, the "Sheepbed" rock was fractured and filled with sulfate minerals when water flowed through subsurface fracture networks. The "Sheepbed" rock indicates a habitable environment characterized by neutral pH, chemical gradients that would have created energy for microbes, and very low salinity, which would have helped the metabolism of any microorganisms that might have been present.Both color images have been white–balanced using the same technique to show roughly what they would look like if they were on Earth.The "true color" image from Opportunity's panoramic camera (Pancam) was acquired on Oct. 6, 2004, while the image from Sheepbed was from Curiosity's Mast Camera on Feb. 18, 2013.](http://cdn2-b.examiner.com/sites/default/files/styles/image_content_width/hash/50/d1/50d1d19e276ca8f42da6a45f26e65393.jpg?itok=GzlMBo-t "These images compare rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars. On the left is "Wopmay" rock, in Endurance Crater, Meridiani Planum, as studied by the Opportunity rover. On the right are the rocks of the "Sheepbed" unit in Yellowknife Bay, in Gale Crater, as seen by Curiosity.The "Wopmay" rock is formed from sandstone, which scientists think were formed partly in the presence of water. They also think the concretions were formed in the presence of water. The "Wopmay" rock records an ancient aqueous environment that was likely too acidic, too nutrient-poor, and too salty for microorganisms to survive.The "Sheepbed" rock, on the other hand, records an ancient aqueous environment that was habitable. While being formed much like the "Wopmay" rock, the "Sheepbed" rock was fractured and filled with sulfate minerals when water flowed through subsurface fracture networks. The "Sheepbed" rock indicates a habitable environment characterized by neutral pH, chemical gradients that would have created energy for microbes, and very low salinity, which would have helped the metabolism of any microorganisms that might have been present.Both color images have been white–balanced using the same technique to show roughly what they would look like if they were on Earth.The "true color" image from Opportunity's panoramic camera (Pancam) was acquired on Oct. 6, 2004, while the image from Sheepbed was from Curiosity's Mast Camera on Feb. 18, 2013.")
On Tuesday, NASA announced that its Curiosity rover has collected a rock sample that indicates that Mars could have supported microbial life at some point in the past.
The sample that was analyzed came from Gale Crater, near the site where Curiosity landed on Aug. 6, 2012, and discovered an ancient streambed in September. The sedimentary rock that was part of an ancient streambed descending from the rim of Gale Crater contained carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur, all of which play important roles in lifeforms on Earth.
“A fundamental question for this mission is whether Mars could have supported a habitable environment. From what we know now, the answer is yes,” said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington, DC.
“Clay minerals make up at least 20 percent of the composition of this sample,” said David Blake, principal investigator for the CheMin instrument at NASA's Ames Research Center in Moffett Field, Calif.
The Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) systems onboard the Curiosity rover indicate that the Yellowknife Bay area currently being explored by the rover was once at the end of either an ancient river system or an intermittently wet lacustrine environment. The bedrock in the area is fine-grained mudstone that shows evidence of multiple periods of intermittently wet conditions, including nodules and veins. This ancient wet environment, unlike some others on Mars, was not strongly acidic, very salty, or lacking in chemical gradients.
The rocks in the area contain clay minerals, as well as sulfate minerals. The presence of calcium sulfate indicates neutral or mildly alkaline pH, in the 7-8 range. The clay minerals result from fresh water mixing with igneous minerals. There is also a gradient of oxidized, less-oxidized, and a small amount of non-oxidized chemicals, which could have provided an energy source for microorganisms. This electrochemical gradient was first hinted at when the drill cuttings were revealed to be gray rather than red.
“The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,” said Paul Mahaffy, principal investigator of the SAM suite of instruments at NASA's Goddard Space Flight Center in Greenbelt, Md.
“We have characterized a very ancient, but strangely new 'gray Mars' where conditions once were favorable for life. Curiosity is on a mission of discovery and exploration, and as a team we feel there are many more exciting discoveries ahead of us in the months and years to come,” said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology in Pasadena, Calif.
Observations will continue to be made in the Yellowknife Bay area for several months before the rover is driven to Mount Sharp, the central mound inside Gale Crater. There, scientists will study the layers of minerals that are exposed, which may provide more information about the diversity and duration of habitable environmental conditions.
NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Curiosity project for NASA's Science Mission Directorate in Washington, DC.
![These images compare rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars. On the left is "Wopmay" rock, in Endurance Crater, Meridiani Planum, as studied by the Opportunity rover. On the right are the rocks of the "Sheepbed" unit in Yellowknife Bay, in Gale Crater, as seen by Curiosity.The "Wopmay" rock is formed from sandstone, which scientists think were formed partly in the presence of water. They also think the concretions were formed in the presence of water. The "Wopmay" rock records an ancient aqueous environment that was likely too acidic, too nutrient-poor, and too salty for microorganisms to survive.The "Sheepbed" rock, on the other hand, records an ancient aqueous environment that was habitable. While being formed much like the "Wopmay" rock, the "Sheepbed" rock was fractured and filled with sulfate minerals when water flowed through subsurface fracture networks. The "Sheepbed" rock indicates a habitable environment characterized by neutral pH, chemical gradients that would have created energy for microbes, and very low salinity, which would have helped the metabolism of any microorganisms that might have been present.Both color images have been white–balanced using the same technique to show roughly what they would look like if they were on Earth.The "true color" image from Opportunity's panoramic camera (Pancam) was acquired on Oct. 6, 2004, while the image from Sheepbed was from Curiosity's Mast Camera on Feb. 18, 2013.](http://cdn2-b.examiner.com/sites/default/files/styles/profile_large/hash/18/70/1870535f288edd2160b1f91351f83604.jpg?itok=nR0sXlqb "These images compare rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars. On the left is "Wopmay" rock, in Endurance Crater, Meridiani Planum, as studied by the Opportunity rover. On the right are the rocks of the "Sheepbed" unit in Yellowknife Bay, in Gale Crater, as seen by Curiosity.The "Wopmay" rock is formed from sandstone, which scientists think were formed partly in the presence of water. They also think the concretions were formed in the presence of water. The "Wopmay" rock records an ancient aqueous environment that was likely too acidic, too nutrient-poor, and too salty for microorganisms to survive.The "Sheepbed" rock, on the other hand, records an ancient aqueous environment that was habitable. While being formed much like the "Wopmay" rock, the "Sheepbed" rock was fractured and filled with sulfate minerals when water flowed through subsurface fracture networks. The "Sheepbed" rock indicates a habitable environment characterized by neutral pH, chemical gradients that would have created energy for microbes, and very low salinity, which would have helped the metabolism of any microorganisms that might have been present.Both color images have been white–balanced using the same technique to show roughly what they would look like if they were on Earth.The "true color" image from Opportunity's panoramic camera (Pancam) was acquired on Oct. 6, 2004, while the image from Sheepbed was from Curiosity's Mast Camera on Feb. 18, 2013.")
![This false-color map shows the area within Gale Crater on Mars, where NASA's Curiosity rover landed on Aug. 5, 2012 PDT (Aug. 6, 2012 EDT) and the location where Curiosity collected its first drilled sample at the "John Klein" rock. The image merges topographic data with thermal inertia data that record the ability of the surface to hold onto heat. Red indicates a surface material that retains its heat longer into the evening than other areas, suggesting differences relative to its surroundings. Curiosity crossed the boundary from lower thermal inertia values to higher values on Dec. 8, 2012 while driving down into an area known as "Yellowknife Bay". The black oval indicates the targeted landing area for the rover, known as the "landing ellipse," and the black cross shows where the rover actually touched down at what has since been named the Bradbury Landing site. The blue circle indicates where the John Klein drill site is within the Yellowknife Bay area.An alluvial fan, or fan-shaped deposit where debris spread out downslope, has been highlighted in lighter colors for better viewing. On Earth, alluvial fans often are formed by water flowing downslope. The John Klein outcrop is part of a geologic layer, known as "Sheepbed," which is a mudstone with abundant evidence for ancient aqueous processes. It seems likely that sediments were transported downhill from the eroding crater rim and became part of alluvial fan systems. The materials then flowed out where water and sediments accumulated to form a habitable environment represented by the Sheepbed mudstone.This image was obtained by the Thermal Emission Imaging System on NASA's Odyssey orbiter.](http://cdn2-b.examiner.com/sites/default/files/styles/profile_large/hash/be/9c/be9c20c5c7e1eda88dbae56ada993f59.jpg?itok=XDXqCW1W "This false-color map shows the area within Gale Crater on Mars, where NASA's Curiosity rover landed on Aug. 5, 2012 PDT (Aug. 6, 2012 EDT) and the location where Curiosity collected its first drilled sample at the "John Klein" rock. The image merges topographic data with thermal inertia data that record the ability of the surface to hold onto heat. Red indicates a surface material that retains its heat longer into the evening than other areas, suggesting differences relative to its surroundings. Curiosity crossed the boundary from lower thermal inertia values to higher values on Dec. 8, 2012 while driving down into an area known as "Yellowknife Bay". The black oval indicates the targeted landing area for the rover, known as the "landing ellipse," and the black cross shows where the rover actually touched down at what has since been named the Bradbury Landing site. The blue circle indicates where the John Klein drill site is within the Yellowknife Bay area.An alluvial fan, or fan-shaped deposit where debris spread out downslope, has been highlighted in lighter colors for better viewing. On Earth, alluvial fans often are formed by water flowing downslope. The John Klein outcrop is part of a geologic layer, known as "Sheepbed," which is a mudstone with abundant evidence for ancient aqueous processes. It seems likely that sediments were transported downhill from the eroding crater rim and became part of alluvial fan systems. The materials then flowed out where water and sediments accumulated to form a habitable environment represented by the Sheepbed mudstone.This image was obtained by the Thermal Emission Imaging System on NASA's Odyssey orbiter.")
![This side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from the Martian surface by NASA's Curiosity rover. These images, made from data obtained by Curiosity's Chemistry and Mineralogy instrument (CheMin), show the patterns obtained from a drift of windblown dust and sand called "Rocknest" and from a powdered rock sample drilled from the "John Klein" bedrock.The presence of abundant clay minerals in the John Klein drill powder and the lack of abundant salt suggest a fresh water environment. The presence of calcium sulfates rather than magnesium or iron sulfates (as found at Meridiani Planum by NASA's Mars Exploration Rover Opportunity) suggests a neutral to mildly alkaline pH environment. The Rocknest sand shadow mineralogy suggests a dry, aeolian environment with low water activity. The John Klein mineralogy suggests a lacustrine environment with high water activity.As seen on the left, the Rocknest data reveal abundant plagioclase feldspar, pyroxene and olivine minerals. The data also indicate reveal small amounts of magnetite and anhydrite. In addition, the Rocknest sample contains 25 to 35 percent amorphous material.X-ray diffraction analysis of the John Klein drill powder reveals abundant phyllosilicate, plagioclase feldspar, pyroxene, magnetite and olivine. Alternatively, the clay minerals could have been transported by water from sources higher up the sediment fan to form the John Klein mineral assemblage. The region of the pattern indicating the phyllosilicates is labeled in the annotated version of this image. The data also show minor amounts of anhydrite and bassanite. The John Klein sample also contains about 20 percent amorphous material.](http://cdn2-b.examiner.com/sites/default/files/styles/profile_large/hash/57/4c/574cf28bc2030d80b3312b126c2dd111.jpg?itok=G3IW-_op "This side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from the Martian surface by NASA's Curiosity rover. These images, made from data obtained by Curiosity's Chemistry and Mineralogy instrument (CheMin), show the patterns obtained from a drift of windblown dust and sand called "Rocknest" and from a powdered rock sample drilled from the "John Klein" bedrock.The presence of abundant clay minerals in the John Klein drill powder and the lack of abundant salt suggest a fresh water environment. The presence of calcium sulfates rather than magnesium or iron sulfates (as found at Meridiani Planum by NASA's Mars Exploration Rover Opportunity) suggests a neutral to mildly alkaline pH environment. The Rocknest sand shadow mineralogy suggests a dry, aeolian environment with low water activity. The John Klein mineralogy suggests a lacustrine environment with high water activity.As seen on the left, the Rocknest data reveal abundant plagioclase feldspar, pyroxene and olivine minerals. The data also indicate reveal small amounts of magnetite and anhydrite. In addition, the Rocknest sample contains 25 to 35 percent amorphous material.X-ray diffraction analysis of the John Klein drill powder reveals abundant phyllosilicate, plagioclase feldspar, pyroxene, magnetite and olivine. Alternatively, the clay minerals could have been transported by water from sources higher up the sediment fan to form the John Klein mineral assemblage. The region of the pattern indicating the phyllosilicates is labeled in the annotated version of this image. The data also show minor amounts of anhydrite and bassanite. The John Klein sample also contains about 20 percent amorphous material.")
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