* Astronomy

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RE: SETI

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Title: Impact of technological synchronicity on prospects for SETI
Authors: Marko Horvat, Anamari Nakic, Ivana Otocan

For over 50 years, astronomers have searched the skies for evidence of electromagnetic signals from extraterrestrial civilizations that have reached or surpassed our level of technological development. Although often overlooked or given as granted, the parallel use of an equivalent communication technology is a necessary prerequisite for establishing contact in both leakage and deliberate messaging strategies. Civilization advancements, especially accelerating change and exponential growth, lessen the perspective for a simultaneous technological status of civilizations thus putting hard constraints on the likelihood of a dialogue. In this paper we consider the mathematical probability of technological synchronicity of our own and a number of other hypothetical extraterrestrial civilizations and explore the most likely scenarios for their concurrency. If SETI projects rely on a fortuitous detection of leaked interstellar signals (so called "eavesdropping") then without any prior assumptions N \geq 138-4991 Earth-like civilizations have to exist at this moment in the Galaxy for the technological usage synchronicity probability p \geq 0.95 in the next 20 years. We also show that since the emergence of complex life, coherent with the hypothesis of the Galactic habitable zone, N \geq 1497 extraterrestrial civilizations had to be created in the Galaxy in order to achieve the same estimated probability in the technological possession synchronicity which corresponds to the deliberate signalling scenario.

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Title: Candidate Identification and Interference Removal in SETI@home
Authors: Eric J. Korpela, Jeff Cobb, Matt Lebofsky, Andrew Siemion, Joshua von Korff, Robert C. Bankay, Dan Werthimer, David Anderson (Space Sciences Laboratory, University of California)

SETI@home, a search for signals from extraterrestrial intelligence, has been recording data at the Arecibo radio telescope since 1999. These data are sent via the Internet to the personal computers of volunteers who have donated their computers' idle time toward this search. To date, SETI@home volunteers have detected more than 4.2 billion potential signals. While essentially all of these potential signals are due to random noise processes, radio frequency interference (RFI), or interference processes in the SETI@home instrumentation, it is possible that a true extraterrestrial transmission exists within this database. Herein we describe the process of interference removal being implemented in the SETI@home post-processing pipeline, as well as those methods being used to identify candidates worthy of further investigation.

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Donations revive SETI quest

The SETI Institute's search for extraterrestrial intelligence is back on track, thanks to more than $200,000 in donations from thousands of fans.
Among the contributors are Jodie Foster, the actress who played a SETI researcher in the movie "Contact"; science-fiction writer Larry Niven, creator of the "Ringworld" series of novels; and Apollo 8 astronaut Bill Anders, who flew around the moon in 1968.
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SETI has been exploring many funding possibilities, including an offer to track space debris for the U.S. Air Force.
In June, asking for support from enthusiasts and the general public, SETI began a campaign to raise $200,000 by August and combine that amount with private donations already collected. If successful, the project would resume for awhile, but Pierson admits the project costs about $2.5 million a year.
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One million amateur stargazers to help scientists try and spot advanced alien life on another planet

Stargazers around the world are helping scientists to try and detect signals from an advanced civilisation on another planet.
In February, Nasa announced that its Kepler space telescope had identified 1,235 possible planets, some of them 'habitable zones', during its first four months in orbit.
Now astronomers at the University of California, Berkeley, are aiming a radio telescope at the most Earth-like of these worlds to see if the can spot any signs of life.
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Cutbacks in funding force UFO hunting telescopes to close

The multi-million dollar American SETI Institute has fallen victim to government cuts.
It has had to shut down a series of telescopes that have been scanning the universe for extra-terrestrial messages.
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Would extraterrestrials like to listen to our music?

Doug Vakoch of the SETI Institute believes music might identify us on physical as well as cultural grounds for aliens that don't know us from Luke Skywalker and a Tatooine Cantina Band.
Vakoch has collaborated with music composer Andrew Kaiser of Carnegie Mellon University in Pittsburgh to create musical messages that might one day be sent to distant worlds. Their work is in harmony with other cosmic communication efforts, like the Voyager Golden Record and "The First Theremin Concert for Aliens," that have already been lofted into space.

This podcast reviews the efforts of these Extraterrestrial DJs.

Source

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Title: Too Damned Quiet?
Authors: Adrian Kent (DAMTP, University of Cambridge and Perimeter Institute)

It is often suggested that extraterrestrial life sufficiently advanced to be capable of interstellar travel or communication must be rare, since otherwise we would have seen evidence of it by now. This in turn is sometimes taken as indirect evidence for the improbability of life evolving at all in our universe. A couple of other possibilities seem worth considering. One is that life capable of evidencing itself on interstellar scales has evolved in many places but that evolutionary selection, acting on a cosmic scale, tends to extinguish species which conspicuously advertise themselves and their habitats. The other is that -- whatever the true situation -- intelligent species might reasonably worry about the possible dangers of self-advertisement and hence incline towards discretion. These possibilities are discussed here, and some counter-arguments and complicating factors are also considered.

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Title: Extrasolar Asteroid Mining as Forensic Evidence for Extraterrestrial Intelligence
Authors: Duncan Forgan, Martin Elvis

The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures which may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without extraterrestrial involvement. Therefore signatures of TAM are not detections of ETI in their own right, but as part of "piggy-back" studies carried out in tandem with conventional debris disc research, they could provide a means of identifying unusual candidate systems for further study using other SETI techniques.

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