1. Searching for Life FYOS

2. = feature whose presence or abundance can be attributed to life Biomarkers (=biosignatures)

3. Remote Detection of Life Sign We will not be able to “resolve” the extrasolar planet We will not be able to “resolve” the extrasolar planet Everything we learn about the planet will be obtained from disk-averaged data. Everything we learn about the planet will be obtained from disk-averaged data. The signs of life must be a global phenomenon The signs of life must be a global phenomenon

4. Phase and Seasonal Variations Viewing Angle Differences

5. Vegetation signature

6. Surface Biosignatures : Vegetation “Red-Edge” Vegetation Red-Edge

7. Spectra of Terrestrial Planet in Solar System Terrestrial planets in our Solar System offer diverse spectra that will be a set of nice references to exoplanet! O2O2 Iron oxides CO 2 H2OH2OH2OH2O EARTH-CIRRUS VENUS X 0.60 MARS EARTH-OCEAN H2OH2O H2OH2O H 2 O ice ? O3O3 O2O2

8. Modern Earth 355ppm CO 2 Earth’s changing appearance at IR

9. Proterozoic 0.1PAL O 2 100ppm CH 4 15% decrease in ozone column depth Segura, Krelove, Kasting, Sommerlatt,Meadows,Crisp,Cohen Changing Biosignatures with time Mid-Proterozoic Earth-like atmospheres show strong signatures from both CH 4 and O 3

10. Archean N 2 99.8% 2000ppm CO 2 1000ppm CH 4 100ppm H 2 Karecha, Kasting, Segura, Meadows, Crisp, Cohen Changing Biosignatures with time

11. CO 2 CH 3 Cl CH 4 O 3 + N2ON2O H2OH2O Earth AD Leo planet Earth-like Planets Around M Stars Segura et al., Astrobiology, 2005.

12. Can we detect Biosignatures with TPF-C?

13. Terrestrial Planet Finders Direct detection of planets Launch 2015? Terrestrial Planet Finder NASA Darwin ESA

14. TPF survey range 25,000 Ly radius of ~200 Ly

15. Level of Technological Advancement Nikolai Kardashev (1932 -- ) : based on the amount of usable energy at alien’s disposal. Nikolai Kardashev (1932 -- ) : based on the amount of usable energy at alien’s disposal. 1.Type I – planetary civilizations : use the resources of their home planet (us!) energy usage upto 10 17 Watts 2.Type II – stellar civilizations : a civilization that is able to harness all of the power available from a single star energy usage up to 10 26 Watts 3.Type III – Galactic civilizations : can employ the resources of the entire galaxy energy usage of 10 37 Watts

16. Detecting Type II civilizations If we capture the energy released by the Sun for just 1 second… If we capture the energy released by the Sun for just 1 second…  enough energy for us to live next 1 million years! Advanced civilization, in a full scale usage of their host star energy, could have built a thin-wall energy collecting sphere around their star Advanced civilization, in a full scale usage of their host star energy, could have built a thin-wall energy collecting sphere around their star  Dyson sphere

17. Dyson Sphere in the Startrek Seen from the USS Enterprise bridge

18. Dyson Sphere in the Startrek The Enterprise in orbit around the Dyson sphere

19. Variants of Dyson Sphere Dyson Ring Dyson Swarm

20. Other Attempts (or suggestions) Artifacts which can be detectable from a great distance… Artifacts which can be detectable from a great distance… Karl Gauss (1777-1855) suggested planting trees in Siberia in the form of a right triangle so that it can be recognized by peoples on the Moon… Karl Gauss (1777-1855) suggested planting trees in Siberia in the form of a right triangle so that it can be recognized by peoples on the Moon… Dig trenches in the Sahara in various geometric shapes and fill them with oil and lit. Dig trenches in the Sahara in various geometric shapes and fill them with oil and lit.

21. Alien Artifacts Instead of sending a signal, advanced aliens might have visited Earth already and buried their instruction somewhere in the Solar System! Some believe that UFOs, crop circles, etc. are those… Some believe that UFOs, crop circles, etc. are those… 2001: A Space Odyssey : Advanced alien being buried their signaling device under the ground of the Moon. 2001: A Space Odyssey : Advanced alien being buried their signaling device under the ground of the Moon.

22. Best to places to hide Lagrange Points Lagrange Points

23. Next Presentations (~ 5 min long) Z. Rindik : “SETI Wow! signal”  Feb 29 Z. Rindik : “SETI Wow! signal”  Feb 29 On Mar 7 C.Barmore & G. Chant : “SETI debate : Zuckerman” C.Barmore & G. Chant : “SETI debate : Zuckerman” S. Jordan & T. West : “SETI debate : Shostak” S. Jordan & T. West : “SETI debate : Shostak”