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The Great Silence - the Controversy Concerning Extraterrestrial Intelligent Life

The Great Silence - the Controversy Concerning Extraterrestrial Intelligent Life | Fun science and engineering | Scoop.it

Here is the most detailed and comprehensive analysis of the so-called "Fermi Paradox" or "The Great Silence"... the puzzling fact that we see no signs of advanced civilizations among the stars. Nor evidence that Earth was ever even visited, during the two billion years that it has been prime real estate, with an oxygen-rich atmosphere. Many theories have been offered fervently by very smart people, each of them convinced that he or she has the aha-answer. But way back in 1983 I published what is still - to this day - the only major review article about alien contact, surveying almost a hundred different hypotheses and ranking them according to plausibility. Surprisingly, there have been almost no new ideas since then, though plenty of heated opinion! (Quarterly Journal of Royal Astronomical Society, fall1983, v.24, pp283-309)


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A mad scientist's guide to re-engineering the planet | Grist

A mad scientist's guide to re-engineering the planet | Grist | Fun science and engineering | Scoop.it
Climate change? Rising seas? Monster storms? Aw hell, we can fix that! It's called geoengineering!
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Dyson sphere hunt using Kepler data - Looking for Kardashev Type II civilizations

Dyson sphere hunt using Kepler data - Looking for Kardashev Type II civilizations | Fun science and engineering | Scoop.it

Freeman Dyson hypothesized the vast structures over fifty years ago that could ring or completely enclose their parent star. Such structures, the work of a Kardashev Type II civilization — one capable of drawing on the entire energy output of its star — would power the most power-hungry society and offer up reserves of energy that would support its continuing expansion into the cosmos, if it so chose.

 

Marcy’s plan is to look at a thousand Kepler systems for telltale evidence of such structures by examining changes in light levels around the parent star. Interestingly, the grant of $200,000 goes beyond the Dyson sphere search to look into possible laser traffic among extraterrestrial civilizations. Says Marcy: "Technological civilizations may communicate with their space probes located throughout the galaxy by using laser beams, either in visible light or infrared light. Laser light is detectable from other civilizations because the power is concentrated into a narrow beam and the light is all at one specific color or frequency. The lasers outshine the host star at the color of the laser."

 

The topic of Dyson spheres calls Richard Carrigan to mind. The retired Fermilab physicist has studied data from the Infrared Astronomical Satellite (IRAS) to identify objects that radiate waste heat in ways that imply a star completely enclosed by a Dyson sphere. This is unconventional SETI in that it presumes no beacons deliberately announcing themselves to the cosmos, but instead looks for signs of civilization that are the natural consequences of physics.

 

Carrigan has estimated that a star like the Sun, if enclosed with a shell at the radius of the Earth, would re-radiate its energies at approximately 300 Kelvin. Marcy will turn some of the thinking behind what Carrigan calls ‘cosmic archaeology’ toward stellar systems we now know to have planets, thanks to the work of Kepler. Ultimately, Carrigan’s ‘archaeology’ could extend to planetary atmospheres possibly marked by industrial activity, or perhaps forms of large-scale engineering other than Dyson spheres that may be acquired through astronomical surveys and remain waiting in our data to be discovered. All this reminds us once again how the model for SETI is changing.


Via Apmel, Dr. Stefan Gruenwald
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