Re: Why Aren't The Aliens Here Already?

From	HVAC <Mr.HVAC@gmail.com>
Newsgroups	sci.physics, alt.astronomy, alt.atheism
Subject	Re: Why Aren't The Aliens Here Already?
Date	2015-08-26 07:43 -0400
Organization	A noiseless patient Spider
Message-ID	<mrk8ki$65j$1@dont-email.me> (permalink)
References	<ZcKdndikAd71dkHInZ2dnUU7-QOdnZ2d@giganews.com>

Cross-posted to 3 groups.

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On 8/25/2015 6:25 PM, Sam Wormley wrote:
> Why Aren't The Aliens Here Already?
>> http://www.npr.org/sections/13.7/2015/05/27/409670639/why-arent-the-aliens-here-already
>>
>
>> If we learned we're the only ones looking into the night sky, it'd be
>> impossibly lonely. But it might also mean there's something holding
>> all beings from a higher state, which may spell our doom too.

Von Neumann Machine.

It has been theorized that a self-replicating starship utilizing 
relatively conventional theoretical methods of interstellar travel 
(i.e., no exotic faster-than-light propulsion, and speeds limited to an 
"average cruising speed" of 0.1c.) could spread throughout a galaxy the 
size of the Milky Way in as little as half a million years.

This leads us to the Fermi Paradox.

(From Wiki)
In 1981, Frank Tipler put forth an argument that extraterrestrial 
intelligences do not exist, based on the absence of von Neumann probes. 
Given even a moderate rate of replication and the history of the galaxy, 
such probes should already be common throughout space and thus, we 
should have already encountered them. Because we have not, this shows 
that extraterrestrial intelligences do not exist. This is thus a 
resolution to the Fermi paradox – that is, the question of why we have 
not already encountered extraterrestrial intelligence if it is common 
throughout the universe.

A response[4] came from Carl Sagan and William Newman. Now known as 
Sagan's Response, it pointed out that in fact Tipler had underestimated 
the rate of replication, and that von Neumann probes should have already 
started to consume most of the mass in the galaxy. Any intelligent race 
would therefore, Sagan and Newman reasoned, not design von Neumann 
probes in the first place, and would try to destroy any von Neumann 
probes found as soon as they were detected. As Robert Freitas[5] has 
pointed out, the assumed capacity of von Neumann probes described by 
both sides of the debate are unlikely in reality, and more modestly 
reproducing systems are unlikely to be observable in their effects on 
our Solar System or the Galaxy as a whole.

-- 
"Are we going to fight or are we going to stand around all day?"
https://goo.gl/TU0Xr6

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Why Aren't The Aliens Here Already? Sam Wormley <swormley1@gmail.com> - 2015-08-25 17:25 -0500
  Why Aren't The Aliens Here Already? john <johnsefton288@gmail.com> - 2015-08-25 16:09 -0700
  Re: Why Aren't The Aliens Here Already? Double-A <double-a3@hush.com> - 2015-08-25 16:15 -0700
    Re: Why Aren't The Aliens Here Already? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-26 09:39 -0700
      Re: Why Aren't The Aliens Here Already? "hanson" <hanson@quick.net> - 2015-08-26 10:39 -0700
      Re: Why Aren't The Aliens Here Already? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-27 15:12 -0700
  Re: Why Aren't The Aliens Here Already? benj <nobody@gmail.com> - 2015-08-26 00:12 -0400
    Re: Why Aren't The Aliens Here Already? john <johnsefton288@gmail.com> - 2015-08-25 21:23 -0700
      Re: Why Aren't The Aliens Here Already? HVAC <Mr.HVAC@gmail.com> - 2015-08-26 07:47 -0400
        Re: Why Aren't The Aliens Here Already? john <johnsefton288@gmail.com> - 2015-08-26 07:19 -0700
          Re: Why Aren't The Aliens Here Already? benj <none@gmail.com> - 2015-08-26 13:16 -0400
            Re: Why Aren't The Aliens Here Already? HVAC <Mr.HVAC@gmail.com> - 2015-08-27 07:52 -0400
              Re: Why Aren't The Aliens Here Already? BDK <Control@Worldcontrol.com> - 2015-08-27 10:00 -0400
                Re: Why Aren't The Aliens Here Already? HVAC <Mr.HVAC@gmail.com> - 2015-08-27 10:53 -0400
    Re: Why Aren't The Aliens Here Already? HVAC <Mr.HVAC@gmail.com> - 2015-08-26 07:45 -0400
  Re: Why Aren't The Aliens Here Already? The Starmaker <starmaker@ix.netcom.com> - 2015-08-25 23:40 -0700
    Re: Why Aren't The Aliens Here Already? The Starmaker <starmaker@ix.netcom.com> - 2015-08-25 23:41 -0700
      Re: Why Aren't The Aliens Here Already? The Starmaker <starmaker@ix.netcom.com> - 2015-08-26 21:23 -0700
  Re: Why Aren't The Aliens Here Already? HVAC <Mr.HVAC@gmail.com> - 2015-08-26 07:43 -0400

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