1. Search for Extraterrestrial Life: Past, Present, and Future Theodore Bakanas, Graham Greene, Alejandro Herrera, Angeline Paik and Nathan Tan

2. Pre Space Age Ancient Greece – Epicurus and Lucretius and other atomists believed that the gods interference in human affairs was the root of all evil, causing human beings to engage in all manner of vile and foolish activities – Solution: Eliminate religion by embracing a materialist view of the universe Aristotle Rejects Cosmic Pluralism (10 th Century) and sparks new atomist movements Copernicus develops Heliocentric Model

3. Space Age and Beyond (1957-1970) 1957-1958- Sputnik Missions into Earth’s Orbit 1959- Cocconi & Morrison’s “Searching for Interstellar Communication”- Listen at 1420 MHz (neutral hydrogen) 1960-US Pioneer 5 interplanetary probe to Venus 1961-Drake Equation Developed- Focal Point of SETI 1965- Mariner 4 Mission to Mars

4. SEL: 1970-1980 1971: Project Cyclops forms: – Research teams formed Searched for “Earth-like radio signals” – Budget Issues kill project 1973: Pioneer 10 & 11 explore asteroid belt, Jupiter & Saturn – First man-made object to leave the SS via achieving escape velocity – Contained message from Sagan & Drake

5. Plaque in the Pioneer Probes

6. SEL: 1970-1980 1974: Arecibo Message – Message designed by Drake & Sagan emitted from Arecibo telescope in Puerto Rico – Binary radio signal containing important data Data regarding numbers, atomic numbers, nucleotides, DNA & the depiction of a human – Aimed at star cluster M13

7. SEL: 1970-1980 1977: Voyager Probes: – “Voyager golden records” Consisted of images, greetings in various languages, music and natural sounds Unlock with Hydrogen & plated with Uranium for dating – Still extremely far Relying on extraterrestrial life to communicate with Earth Big Ear Radio – 72 second signal – “Wow” – No signal since

8. SEL: 1980-2000 1984: ALH 84001 Discovery – Carbon globules – Potential bacteria-like organism fossils 1992: HRMS – High Resolution Microwave Survey Scanned millions of radio frequencies Shut down after a year – no detected signals 1995: 51 Pegasi b Discovery – First extrasolar planet found in orbit around a main sequence star – Nearly 300 others confirmed since 2008

9. SEL: 1980-2000 1999: SETI@home – Internet public computing project incorporating volunteers Based out of UC Berkeley – Receives data currently from Arecibo – Sign up to volunteer your computer power/data to be used when idle for research/computation – Demonstrated concept of “volunteer computing”

10. Future of SETI SETI Science and Technology Working Group (SSTWG) conclusion for future opportunities for SETI: 1.Continuous narrowband signals in the radio 2.Very short pulsed signal at optical wavelengths

11. Radio Searches Radio telescopes that investigate the cosmos using large radio antennas to detect non- natural radio emissions from a location outside our Solar System Current Projects: – Project Phoenix – SERENDIP – SETI@home – Allen Telescope Array

12. Project Phoenix Nine year project, finished in 2004 – Focused specifically on searching nearby planets for signs of life About 800 stars in a 200 light year range – Used a series of different radio telescopes, mainly the Arecibo in Puerto Rico – Scanned radio channels between.2 and 3.0 gigahertz – resolution of 0.7 hertz per channel – There are no naturally occurring signals at this resolution At the end of the project no evidence of extraterrestrial life was found

13. Arecibo

14. SERENDIP ( Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations) Problem Solved – not enough telescope to go around SERENDIP solves – placed an attachment on Arecibo that operates all the time. Just looks where the telescope is pointed. Theoretically should gather data 24/7 Currently on SERENDIP V – listens to 300 megahertz of radio channels at once – Will have two polarizations Data is farmed out to SETI@home

15. SETI@home Problem solved – not enough computing power for all that data How – a distributed computing effort – Individuals at home run a program that downloads and analyzes telescope data – Runs while the computer is idle Matches the large data problem by throwing large numbers of computers at it

16. Allen Telescope Array (ATA) Formerly known as 1 Hectare Telescope (1hT) Named after Paul Allen (co-founder of Microsoft) – Funded first phase of construction (1 st 42 dishes) Set of 350 (when, if ever completed) dishes that combine to make essentially a 10,000m 2 interferometer – Interferometer: observed waves are superimposed to extract information about the waves (e.g. absorption/emission of celestial bodies, etc.)

17. Allen Telescope Array (ATA)

18. ATA Scientific Goals Lay the foundation of dark energy detection Classify 250,000 extragalactic radio sources Explore the transient sky and discover new/unknown phenomena Survey 1,000,000 stars for SETI emmision to detect an Arecibo strength radar out to 300 pc Measure molecular cloud and star formation properties Plus many more

19. Current Status of ATA Construction planned in 4 stages (42, 98, 206, 350) First 42 dishes began operating in 2007 April 2011, ATA suspended because of lack of funding December 2011, operations resumed

20. Optical SETI Possible that alien civilizations may be using powerful lasers (brief, nanosecond laser pulses) for interstellar communications at optical wavelengths Optical SETI vs. Radio SETI – Smaller and lighter than microwave or radio-emitting devices – Produce higher bandwidths and can consequently send information faster – Interference from natural sources of microwaves more common – Naturally occurring nanosecond pulses of light are most likely nonexistent

21. Optical SETI Problems 1.Highly “monochromatic”: makes it troublesome to figure out what frequency to look for – Emitting light in narrow pulses results in a broad spectrum of emission, spread in frequency becomes higher as the pulse width becomes narrower, making it easier to detect an emission 2.Highly Directional: can easily be blocked by clouds of interstellar dust and Earth would cross its direct line of fire by chance

22. Current Optical SETI focuses Create an automated system to send a pulse to targets at a constant rate – Targets all Sun-like stars with a distance of 100 light-years Create an automatic laser pulse detector system – Detect laser flashes from civilizations attempting contact – Low-cost, two-meter mirror made of carbon composite materials

23. Optical Pulse-Detection Systems Searches nearby stars to detect nanosecond optical pulsed laser beacon signals Existing Programs – Harvard – Princeton – Sevendip: UC Berkeley – Lick Observatory – Columbus Observatory Numerous instances seen, but none seem to be intentional laser signals Extended search for light pulses from optical to infrared wavelengths All programs are being upgraded to a 3 light detector system, making it largely immune to false alarms

24. All-Sky Optical SETI Survey Telescope looks at a stripe of sky measuring 1.6 to 0.2 degrees and reviews all stars in that stripe – Earth’s rotation carries the celestial sphere through that stripe Will take 200 clear nights to survey entire visible sky Cherenkov radiation (light given off when charged cosmic particles plunge through Earth’s atmosphere faster than the speed of light in atmosphere) caused false triggers Recently installed: – New electron boards that will sift data quickly, and store more than before, allowing for false alarms to be sorted out – Upgraded photomultiplier tube detectors that are more sensitive and extend into the infrared