GS Paper - 3 (Space Technology)

NASA's Curiosity rover landed on Mars on 6 August 2012 and since then has roamed Gale Crater taking samples and sent the results back home for researchers to interpret. Analysis of carbon isotopes in sediment samples taken from half a dozen exposed locations, including an exposed cliff, which left researchers with three plausible explanations for the carbon's origin -- cosmic dust, ultraviolet degradation of carbon dioxide, or ultraviolet degradation of biologically produced methane.

What the researchers said

  1. Carbon has two stable isotopes, 12 and 13. By looking at the amounts of each in a substance, researchers could determine specifics about the carbon cycle that occurred, even if it happened a very long time ago.
  2. The amounts of carbon 12 and carbon 13 in our solar system are the amounts that existed at the formation of the solar system.
  3. Both exist in everything, but because carbon 12 reacts more quickly than carbon 13, looking at the relative amounts of each in samples can reveal the carbon cycle.
  4. Curiosity, which has been led by NASA's Jet Propulsion Laboratory in Southern California, has spent the last nine years exploring an area of Gale Crater that has exposed layers of ancient rock.
  5. The rover drilled into the surface of these layers and recovered samples from buried sedimentary layers. Curiosity heated the samples in the absence of oxygen to separate any chemicals.
  6. Spectrographic analysis of a portion of the reduced carbon produced by this pyrolysis showed a wide range of carbon 12 and carbon 13 amounts depending on where or when the original sample formed.
  7. To explain the exceptionally depleted samples, the researchers suggested three possibilities -- a cosmic dust cloud, ultraviolet radiation breaking down carbon dioxide, or ultraviolet degradation of biologically created methane.