SETI@home: a Progress SETI@home: a Progress ReportReport

David P. AndersonDavid P. Anderson

Space Sciences LaboratorySpace Sciences Laboratory

U.C. BerkeleyU.C. Berkeley

A short science lesson

Ionians600-400 BC

Light

Electricity/magnetism

Math

Ptolemy140 AD

Newton1666

Galileo1609

Foucault1849

Greeks Gilbert1600

Oersted, Faraday1820-1830

Leibniz, Newton1670-1700

Gauss, etc.1750-1850

Maxwell’s equations (1862)

“We can scarcely avoid the conclusion that light consistsin the transverse undulations of the same mediumwhich is the cause of electric and magnetic phenomena.”

The Electromagnetic Spectrum

1888: Heinrich Hertz generates radio waves1901: Gugliemo Marconi uses radio to communicate across Atlantic

The Extraterrestrial Life Conjecture:

Is there life outside Earth?

An early idea (Gauss 1820)

Investigating the ELC

• Hard to disprove• Likelihood estimation: Drake’s Equation

N = R×fp×ne×fl×fi×fc×L

– Milky Way: 400 billion stars– 100 billion other galaxies

• To prove: detect life– Actively– Passively

Planet discovery (1996 -)

Doppler shifting of absorption lines

How to detect life

• Physical evidence• Synthetic EM waves

– Radio• Beamed• Omnidirectional

– Optical

• Natural EM waves100,000 light years

What’s there to say?

Civilization knowledge:

• Scientific– Biology, math, etc.

• Technology• Cultural

– Art, literature, music– philosophy

• Social– How to govern

Benefits and dangers

• Sending+: Share legacy; need to send to hear– : Get noticed, invaded

• Listening+: Learn something; social benefits– : Destructive technology; computer

viruses

The latency problem

• Distance may be 1000s of light years

• How to speed up time?• “Contact”: instructions for FTL

machine• Algorithmic communication: send

an oracle

The Galactic Internet

• The Galaxy-Wide Web– http://gww.rigel.4/~kodos/index.html

• Google• Commerce and ad campaigns

– “Got Oxygen?”– Pyramid schemes

• Galactic archive– Civilization as storage device

Radio SETI

• Observation– Sky survey, targeted search

• Compute power spectrum• Pattern-match narrow-band signals• Eliminate man-made interference (RFI)• Rank and re-observe candidates• The “Declaration of Principles”

We, the institutions and individuals participating in the search for extraterrestrial intelligence,…

SETI@home• Use distributed computing• Better data analysis:

– Signal types (Gaussian, spike, pulsed, triplet)

– Multiple frequency resolutions– Multiple drift rates, coherent integration

• Tradeoff: smaller frequency band– 2.5MHz vs. 100 MHz

Datarecorder

screensavers

science DBuser DB

WU storage

splitters

DLT tapes

dataserver

resultqueue

acct.queue

garbagecollector

tape archive,delete

tape backup

master DBredundancy

checking

RFIelimination

repeatdetection

web site

CGI program

web pagegenerator

SETI@home Operations

Achievements of SETI@home

• 1,000,000 years of CPU time in 3 years

• Sustained 35 TeraFLOPs• 1.5E^21 floating-point operations• 3,600,000 users in 226 countries• 40 Terabytes of data processed• 3 billion “events” detected

What’s next?

• New SETI searches– Parkes observatory: southern sky– Multi-beam receivers– Expanded frequency range

• Reanalysis of SETI data• black hole evaporation• Hydrogen map

Berkeley Open Infrastructure for Network Computing (BOINC)

Many possibly applications:– Global climate modeling and prediction– Protein folding, gene mapping– Drug discovery

Research lab X

University Y Public project Z

projects

applications

resource pool

Conclusion

• SETI is a basic unanswered question

• ET contact might revolutionize all areas of human thought and activity

• SETI@home approach can– Enable new computational science– Bridge science/public gap