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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>How do you dim a star at a few Hz rate, Keith asked.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>I answer: you don’t. There is no need to send signals at data rates that high. The only message that needs to be sent out is “Hello galaxy, we are here.” OK, so what is the lowest number of bits needed to send the signal “Hello galaxy, we are here” please?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Imagine a variation on a theme of an MBrain, call it an SBrain, where the S is for… oh I don’t know, Sandberg, or sacrilege or schmike, for instance. Imagine an SBrain is a spherical sun-sized cluster of nodes orbiting about the barycenter of the many nodes. If the density of the nodes is approximately one node per million cubic meters, the SBrain would contain about 1.4E12 nodes.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Imagine the entire trillion node body orbits a star (imagine that star to be like our sun, same brightness, same mass.) With one node per million cubic meters, most of the star’s radiation would pass through the diaphanous body, all but perhaps 5% of it. Imagine that SBrain orbiting the star at about 1 AU, so that its orbit is once a year. An observer positioned in the plane of the orbit would see a slight dimming once a year, for about seven hours from start of dimming to end.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Now imagine a five solar diameters away in the same orbit a second SBrain. The two SBrains travel around the star, causing a double dip in brightness. OK now imagine ten solar diameters back, a third SBrain, then five diameters behind that one another and five diameters back, a third. Another empty ten solar diameters, then a series of five SBrains, separated by the usual five solar diameters. Repeat for seven, then eleven, then thirteen SBrains.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Observers in the plane of those 41 orbiting SBrains would observe a slight dimming of that star in a pattern which cannot be a natural phenomenon, the first six prime numbers in base 1. This dimming could be observed thousands of light years away, and every observer would be well aware of what it meant: an advanced civilization built that. That advanced civilization would realize there is no point in sending out laser signals to dead stars, since most stars are dead. All it would be doing is very passively signaling that it is there, and it is alive.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>But, one might reasonably object, only other stars very nearly in the plane of that orbit would be able to observe the dimming. Sure. But an advanced civilization could go out a bit further, a few solar diameters would be plenty, and create a second ring of SBrains inclined a milliradian to the first, arranged the same way as the first. It would take a bit over a year to dim out the signal compared to the inner ring, but what’s the hurry? If all that civilization is doing is telling the galaxy “Hello galaxy, we are here” well, what’s the big hurry? This old galaxy has been here a long time?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>The advanced civilization could create arbitrarily many such rings, each tilted a milliradian to the adjacent ring inside itself and the adjacent ring outside itself. 3142 such rings would present a prime dimming pattern everywhere.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>The MBrain’s thermal problem does not hinder the SBrain, since the SBrains do not block a significant fraction of the star’s energy. This notion does not form a Kardashev 2 and is not going there, for it realizes the laws of nature do not allow Kardashev 2 using this technology. The accursed second law of thermodynamics spoils everything.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>Why send such a signal? Because as soon as any nearby intelligent civilization realized there was a technologically advanced civilization nearby, it would use its laser to start sending signals to that system. The SBrains would get free intelligence, and identifying which stars contain civilizations capable of receiving signals sent at much higher data rates using a laser, as Keith suggested. Until the SBrains figure out where the live stars are located, the laser is a waste of energy and effort. The SBrain first six prime signal, sent passively identifies where someone is listening.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>BillK, please offer the above to your favorite AI for adjudication.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt'>spike<o:p></o:p></span></p></div></body></html>