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Life in the Universe

Life in the Universe. 029:062 Guest Lecture Catherine Whiting. Life in the Universe. What are the chances of extraterrestrial life in the universe? How common are extrasolar planets ? How many of these planets are suitable for life? (at least earth-like life)

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Life in the Universe

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  1. Life in the Universe 029:062 Guest Lecture Catherine Whiting

  2. Life in the Universe • What are the chances of extraterrestrial life in the universe? • How common are extrasolar planets? • How many of these planets are suitable for life? (at least earth-like life) • What characteristics would this life possess? • How would we make contact?

  3. Extrasolar Planets • Detection Methods

  4. Extrasolar Planets • Detection Methods • Eclipses

  5. Extrasolar Planets • Detection Methods • Doppler Shifts – planet causes star to wobble

  6. Extrasolar Planets • Detection Methods • Imaging HR 8799 Infrared Image Planets only 60 million years old- still glowing from formation

  7. Extrasolar Planets • Detection Methods • Eclipses, Doppler Shifts, Imaging • Subject to selection effects- meaning we tend to detect mostly Jupiter-like planets that are close to their stars because our detection methods are best-suited to detecting Jupiter-like planets • Earth-like planets now being detected - Kepler Mission

  8. Example: Gliese 581 • Red dwarf star • 20.3 light years away • At least 6 known planets- some could support life

  9. Habitable Zone • Life on Earth appears to require water • Planets with water may be the most promising places for life • In order to have liquid water, the temperature of the planet must be between freezing and boiling points • This limits its distance from its star- Habitable Zone-

  10. Habitable Zone

  11. More than 450 new planets have been discovered since 1995

  12. 99% of all organic material consists of 4 elements: Hydrogen, Carbon, Oxygen, Nitrogen

  13. Chemical Abundances in Stars

  14. Ammonia, Methane, Water + Lightning= Amino Acids !

  15. Miller-Urey Experiment • Cosmos Episode 2: time: 46:15 • http://www.youtube.com/watch?v=p1Zh69TB0lU

  16. Drake Equation • Carl Sagan Video: • http://www.youtube.com/watch?v=MlikCebQSlY&feature=related • Carl Sagan translated for rednecks: • http://www.youtube.com/watch?v=DI9ImScQGAo&feature=related

  17. What would aliens look like? • Cosmos Episode 2: time: 52:50 http://www.youtube.com/watch?v=p1Zh69TB0lU

  18. Discussion Questions • Would alien civilizations be hostile? • Are aliens already secretly here? • Colonization, government conspiracy • Would we even be able to comprehend them?

  19. SETI (Search for ExtraTerrestrial Intelligence) • If there are other civilizations out there, are they trying to contact us? • There are active searches for ET signals, mainly in the radio, some using visible light.

  20. Arecibo Message

  21. Voyager

  22. Voyager Decoded

  23. Voyager Message • http://voyager.jpl.nasa.gov/spacecraft/index.html

  24. Discussion Questions • If we were to send another Voyager or Arecibo message, what would you include? • Instruments? • Music? • Videos? • Sounds? • Information?

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