1 / 25

Micro fossil in a meteorite ?

Micro fossil in a meteorite ?. (R. Hoover 2011). Lecture 7: Geologic History of Life. Oldest signatures of life in sedimentary rocks: Microfossils Molecular fossils (mainly lipids) Stromatolites C and S isotopic signatures Pattern of nested similarity. A fossil cyanobacterium

shaw
Download Presentation

Micro fossil in a meteorite ?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Micro fossil in a meteorite ? (R. Hoover 2011)

  2. Lecture 7: Geologic History of Life • Oldest signatures of life in sedimentary rocks: • Microfossils • Molecular fossils (mainly lipids) • Stromatolites • C and S isotopic signatures • Pattern of nested similarity A fossil cyanobacterium in circa 1.5 Gyr old sedimentary rocks - (A. Knoll).

  3. Microscopic fossils in ALH-84001 ?

  4. Methane release on Mars - 2009

  5. A hole on Mars ?

  6. Lecture 9: Habitable zones How do we define a habitable zone (HZ) ? The habitable zone in the Solar System. Life beyond the habitable zone ?

  7. Defining a Habitable Zone: Range of distances from the star where the temperature on some of the surface of a rocky planet allows water to be liquid. (The planet must have enough mass to keep an atmosphere.)

  8. Defining a Habitable Zone:

  9. The phase diagram of pure water:

  10. The phase diagram of pure water:

  11. Three important properties of water: Liquid in range of temperatures favorable to long-chain polymer forming; (2) Solid form (ice) floats in it own liquid - environmental stability; (3) Is a polar molecule - help membrane formation.

  12. The Terrestrial Planets Mercury Venus Earth Mars

  13. Mars - evidence for water

  14. Mars - evidence for water

  15. A changing Habitable Zone: HZ: shaded - now, dashed - once. The Sun, as all stars, evolves (burns its ‘fuel’ and changes structurally) - it will become cooler and larger.

  16. A changing Habitable Zone:

  17. A changing Habitable Zone:

  18. Beyond the HZ: Radiant heating from a parent star is not the only way to provide an energy source: Planetary interiors: radioactive & core heat Deep Biosphere Lab (Sweden): hyperthermophiles at depths of ~ 6 km (80 C). (2) Tidal heating

  19. Beyond the HZ: Titan

  20. Liquid CH4 & Water ice Liquid H2O & Silicate rock :Titan:::Earth Titan properties • 50% silicates, 50% ices; probably differentiated • Atmosphere is >90% N2 and 2-5% CH4 • Ts= 94K, Ps= 1.5 bar Near triple point Similar mechanical strength

  21. Lakes and channels on Titan!

  22. Main points to take home:

More Related