On Thu, Feb 15, 2018 at 12:05 PM, Telmo Menezes <te...@telmomenezes.com> wrote:
> > > *What if nanotech *is* the filter? Then, the civilizations that survive > could be the ones that avoid that trap somehow.* If Drexler style Nanotechnology had been developed anywhere in the galaxy that fact would be obvious by now regardless of if the civilization that originally developed it survived or not. > > * > Another possibility is that nanotech is possible and civilizations > do eventually build dyson spheres around their stars, but have > absolutely no incentive to go beyond their star system -- this is > easily justifiable by the speed of light limit. We haven't seen one of > those either, but it is also not true that there isn't the slightest sign:* > > https://www.seti.org/whats-up-with-tabby-star That article is out of date, a lot of research has been done on Tabby's star since then and things change fast. Several astronomers (including Tabetha Boyajian after whom Tabby's Star is named) have concluded in a peer reviewed article in "Astrophysical Journal" that the puzzling dimming is not caused by a solid object but by microscopic dust particles: https://arxiv.org/pdf/1708.07556.pdf They closely examined the rate of dimming of the ultraviolet light and the infrared light coming from the star and they found the rate of dimming between the two was significantly different; and a Dyson Sphere, completed or not, wouldn't do that. The only thing that would scatter light like that is lots and lots of microscopic dust. Yes it's odd that a mature star like Tabby would have such a thick cloud of dust in orbit around it and nobody is quite sure why it's there, but whatever caused the dust it sure doesn't look like ET is responsible for the dimming. > > > Maybe they are not computationalists Then some disaster must have prevented them from becoming super-intelligent. > > >> > >> So what? Fragmented or not Intelligence >> >> would be a major force effecting the large scale structure of the >> universe. > > > >* * > *A two-star-system civilization would already be fragmented, unless it > is somehow possible to transcend the speed of light constraint.* I have no choice but to repeat myself: So what? Fragmented or not Intelligence would be a major force effecting the large scale structure of the universe. > >> >> All it would take is one individual in one civilization to take an once >> or so of matter and turn it into a Von Neumann Probe > > > *> Can you build an atomic bomb? * If I had some U235 I could make an A-bomb. Making one just takes a lot of effort (aka money) if you only have 2 large hands, but if I had very small hands it would be easy to separate the one U235 atom that I want from the 140 U238 atoms that I don't want. And if I had 6.02*10^23 of those small hands I could just keep doing the same thing over and over and then very soon I'd have enough for a bomb. Making an H-bomb would be more complicated but if I also had some Lithium-6 deuteride I think I know enough to make a reasonable stab at it. Unfortunately there is no great secret that you need to know to make a nuclear weapon and there hasn't been for about 40 years. Every nation that tried to make an H-bomb was successful on their first attempt, and the second H-bomb ever tested on the planet was over 3 times more powerful than expected and ended up killing some Japanese fishermen as a result even though they were well outside the official danger area. In the case of a Dyson Sphere if you know how to make one square foot of it then you know how to make the entire thing because being a sphere one part of it is identical with every other part of it. > > *> but aren't you a bit too quick to assume that a technology that has > only been theorized is necessarily feasible?* Nanotechnology doesn't involve any new laws of physics and we already have an existence proof of a crude form of Nanotechnology developed by mindless random mutation and natural selection, its called life. And intelligence can do a lot better than randomness. > > >> > >> All a Von Neumann probe needs is energy and atoms, carbon being the most >> >> important although other elements would come in handy. Stars provide lots >> of >> >> energy and there are plenty of nice juicy atoms in asteroids and planets. > > > *>All that and the probe itself, which does not exist circa now....* > I know, that is the Fermi paradox. All I have to do is glance at the night sky to know there is no Von Neumann probe in the entire galaxy. But why? Either we're the first or civilizations always get destroyed when they get to our level. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to email@example.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.