2. 10/14/03Prof. Lynn Cominsky1 Class web site: http://glast.sonoma.edu/~lynnc/courses/a305 Office: Darwin 329A and NASA E/PO (707) 664-2655 Best way to reach me: lynnc@charmian.sonoma.edu Astronomy 305/Frontiers in Astronomy

3. 10/14/03Prof. Lynn Cominsky2 Astrobiology Questions (3 weeks) Is there life elsewhere in our Solar system? Is there life elsewhere in our Solar system? Are Earth-like planets common? Are Earth-like planets common? Are we alone? Are we alone?

4. 10/14/03Prof. Lynn Cominsky3 Group 7

5. 10/14/03Prof. Lynn Cominsky4 Are we alone? Weekly radio show with SETI Institute staff: http://www.radioamerica.org 7 PM Sunday nights (PST)

6. 10/14/03Prof. Lynn Cominsky5 Expert Opinions From a conference on the subject featuring scientists and theologists From a conference on the subject featuring scientists and theologists http://www.meta-library.net/cqinterv/alone-frame.html http://www.meta-library.net/cqinterv/alone-frame.html http://www.meta-library.net/cqinterv/alone-frame.html Featuring: Jill Tarter, Alan Guth, Sandra Faber, Seth Shostak, etc. Featuring: Jill Tarter, Alan Guth, Sandra Faber, Seth Shostak, etc.

7. 10/14/03Prof. Lynn Cominsky6 Searching for signs of Intelligence Use form of electromagnetic radiation that travels throughout the Universe Use form of electromagnetic radiation that travels throughout the Universe Visible light – flashes Visible light – flashes Radio waves – continuous signals Radio waves – continuous signals X-rays or gamma-rays – possible but unlikely X-rays or gamma-rays – possible but unlikely Radio waves use least power Radio waves use least power AM radio – amplitude modulation AM radio – amplitude modulation FM radio – frequency modulation FM radio – frequency modulation

8. 10/14/03Prof. Lynn Cominsky7 Optical SETI Searches for pulses that arrive within a nanosecond in 3 coaligned detectors Searches for pulses that arrive within a nanosecond in 3 coaligned detectors Uses Lick 40 inch telescope Uses Lick 40 inch telescope Aims at known star systems or star clusters Aims at known star systems or star clusters

9. 10/14/03Prof. Lynn Cominsky8 SETI Institute/ Project Phoenix 1,000 - 3,000 MHz search band – 1 Mhz at a time 1,000 - 3,000 MHz search band – 1 Mhz at a time 28 million channel Phoenix receiver can accumulate radio energy for minutes 28 million channel Phoenix receiver can accumulate radio energy for minutes Sensitive targeted search, aimed at nearby stars Sensitive targeted search, aimed at nearby stars Parkes 210 foot telescope in New South Wales Australia Greenbank 140 foot telescope in West Virginia

10. 10/14/03Prof. Lynn Cominsky9 Allen Telescope Array Funded by Microsoft executives Paul Allen and Nathan Myhrvold ($12.5 million so far) Funded by Microsoft executives Paul Allen and Nathan Myhrvold ($12.5 million so far) Joint effort by SETI Institute and UC Berkeley Joint effort by SETI Institute and UC Berkeley 350 commercial 6-m satellite dishes covering 100 square meters 350 commercial 6-m satellite dishes covering 100 square meters Will cover frequencies between 1,000 and 10,000 MHz Will cover frequencies between 1,000 and 10,000 MHz

11. 10/14/03Prof. Lynn Cominsky10 SETI/SERENDIP IV Piggyback instrument at the 1000 foot Arecibo radio telescope in Puerto Rico Piggyback instrument at the 1000 foot Arecibo radio telescope in Puerto Rico 40 spectrum analyzer boards working in parallel 40 spectrum analyzer boards working in parallel Radio wavelengths are best due to low obscuration over great distances Radio wavelengths are best due to low obscuration over great distances

12. 10/14/03Prof. Lynn Cominsky11 SERENDIP/SETI@home 168 million channels every 1.7 seconds in a 100 MHz band centered at 1.42 GHz 168 million channels every 1.7 seconds in a 100 MHz band centered at 1.42 GHz = 35 Gbytes/day! = 35 Gbytes/day! Break it up into small pieces and let others help analyze the data Break it up into small pieces and let others help analyze the data Each download sends 107 s of 10 kHz data plus some supporting information = 0.3 Mbytes Each download sends 107 s of 10 kHz data plus some supporting information = 0.3 Mbytes

13. 10/14/03Prof. Lynn Cominsky12 Message Construction What would a signal look like from an alien being? What would a signal look like from an alien being? Frank Drake proposed to send a digital pattern that is given in your handout Frank Drake proposed to send a digital pattern that is given in your handout Try to figure out how to rearrange it to make the second image shown in the handout Try to figure out how to rearrange it to make the second image shown in the handout What could the areas 1-5 mean? What could the areas 1-5 mean?

14. 10/14/03Prof. Lynn Cominsky13 Message Construction This is the only signal we have deliberately sent at high power (using Arecibo radio telescope) This is the only signal we have deliberately sent at high power (using Arecibo radio telescope) 1679 bits = 73 lines x 23 bits per line 1679 bits = 73 lines x 23 bits per line Transmission took 3 minutes Transmission took 3 minutes It was aimed at M31, a globular cluster near the edge of our galaxy It was aimed at M31, a globular cluster near the edge of our galaxy

15. 10/14/03Prof. Lynn Cominsky14 Drake equation N = R * × f p × n e × f l × f i × f c × L where N: number of communicative civilizations in galaxy R * : rate of formation of suitable stars in galaxy f p : fraction of stars with planetary systems n e : number of planets per system suitable for life f l : fraction of planets which actually have life f i : fraction of those planets with intelligent life f c : fraction of those which can communicate L : lifetime of civilization

16. 10/14/03Prof. Lynn Cominsky15 Drake Equation Activity Take the worksheet and use it to make your own estimate of the number of civilizations in our Galaxy Take the worksheet and use it to make your own estimate of the number of civilizations in our Galaxy

17. 10/14/03Prof. Lynn Cominsky16 Drake equation Rough answer: there are as many communicative civilizations per galaxy as their lifetimes in years – estimated at about 10,000 civilizations per galaxy Rough answer: there are as many communicative civilizations per galaxy as their lifetimes in years – estimated at about 10,000 civilizations per galaxy BUT: in RARE EARTH by Ward and Brownlee BUT: in RARE EARTH by Ward and Brownlee Jupiter protects us from incoming comets and asteroids which could cause major extinctions Jupiter protects us from incoming comets and asteroids which could cause major extinctions Solar systems can’t be too close to galaxy center Solar systems can’t be too close to galaxy center Solar systems can’t be too far away either Solar systems can’t be too far away either Planets cannot have elliptical orbits Planets cannot have elliptical orbits Only life forms (besides Earth) will be single-celled organisms like bacteria Only life forms (besides Earth) will be single-celled organisms like bacteria

18. 10/14/03Prof. Lynn Cominsky17 Do you think life exists on other planets? If so, where? And why? And what type? A) In our solar system? B) In our galaxy? C) In the Universe? Question to ponder: Explain your reasoning on your worksheet

19. 10/14/03Prof. Lynn Cominsky18 Alien Bandstand A recording executive looking for his next big hit has turned to the heavens. He has found a peculiar signal in some radio telescope data and he is convinced that it is music from an alien civilization. He is offering it for sale. A recording executive looking for his next big hit has turned to the heavens. He has found a peculiar signal in some radio telescope data and he is convinced that it is music from an alien civilization. He is offering it for sale. Your mission: Determine if this signal really is an alien tune! Your mission: Determine if this signal really is an alien tune!

20. 10/14/03Prof. Lynn Cominsky19 Wave Review Wavelength – distance between two crests or troughs in a wave in space Wavelength – distance between two crests or troughs in a wave in space Period – time it takes for 1 wave to pass by Period – time it takes for 1 wave to pass by Period is also the Period is also the distance between two crests or troughs in time

21. 10/14/03Prof. Lynn Cominsky20 Let’s play the game! You will meet some interesting characters You will meet some interesting characters You will meet some real scientists You will meet some real scientists You will have three tools to use to take the data needed to solve the mystery You will have three tools to use to take the data needed to solve the mystery There will be a notebook to write down your findings so you can remember things There will be a notebook to write down your findings so you can remember things There will be a quiz at the end There will be a quiz at the end

22. 10/14/03Prof. Lynn Cominsky21 Web Resources SERENDIP http://seti.ssl.berkeley.edu/serendip/serendip.html SERENDIP http://seti.ssl.berkeley.edu/serendip/serendip.html http://seti.ssl.berkeley.edu/serendip/serendip.html SETI@home SETI@home http://setiathome.ssl.berkeley.edu/ http://setiathome.ssl.berkeley.edu/ http://setiathome.ssl.berkeley.edu/ SETI Institute SETI Institute http://www.seti-inst.edu/ http://www.seti-inst.edu/ http://www.seti-inst.edu/ Rare Earth Debates: http://www.space.com/scienceastronomy/rare_earth _1_020715.html Rare Earth Debates: http://www.space.com/scienceastronomy/rare_earth _1_020715.html Space Mysteries: http://mystery.sonoma.edu Space Mysteries: http://mystery.sonoma.edu