Do note l professori, that this idea even to a shmoop like myself occurred
decades ago as a explanation over how or why no ETI signals! So I am real good
with your comment and observation that yeah how well a radio signal propagates
through the Milky Way may be highly and profoundly limited. So I'm not exactly
biting through my lower lip at your reminder. And I say thanks! Signals no
propagate, signals no get received. No ticket no shirty. And I say thank ee'
master.
Sent from the all new AOL app for Android
On Tue, May 24, 2022 at 6:58 AM, Lawrence
Crowell<goldenfieldquaterni...@gmail.com> wrote: Sorry to say, but radio
signals may not make it that far through the galaxy, Charged plasma in
interstellar space may attenuate any EM signal.
LC
On Tue, May 24, 2022 at 12:04 AM <spudboy...@aol.com> wrote:
And, there is this article-
How advanced civilizations could leave us a message of their presence.
We Were Here - Nautilus | Science Connected
Seems like radio would be a lot easier? Maybe this would offer up aliens with a
very large budget?
-----Original Message-----
From: spudboy100 via Everything List <everything-list@googlegroups.com>
To: goldenfieldquaterni...@gmail.com <goldenfieldquaterni...@gmail.com>;
everything-list@googlegroups.com <everything-list@googlegroups.com>
Sent: Mon, May 23, 2022 11:27 pm
Subject: Re: Self-Replicating Robots and Galactic Domination
Then, there's this!
Planets of binary stars as possible homes for alien life -- ScienceDaily
Tatooine!
-----Original Message-----
From: Lawrence Crowell <goldenfieldquaterni...@gmail.com>
To: Everything List <everything-list@googlegroups.com>
Sent: Mon, May 23, 2022 9:40 am
Subject: Re: Self-Replicating Robots and Galactic Domination
On Monday, May 23, 2022 at 7:22:47 AM UTC-5 johnk...@gmail.com wrote:
On Sun, May 22, 2022 at 7:18 PM Lawrence Crowell <goldenfield...@gmail.com>
wrote:
>I suspect there may only be a few thousand planets with complex life in any
>galaxy. I would then say that given life has been here in complex form for 600
>million years and that Homo sapiens have been here 100,000 years this means at
>any given time using this as a guide each planet with complex life has a
>1.7x10^{-4} probability of having intelligent life. This is even smaller when
>one considers how long we have had advanced technology, or about 3x10^{-7}. So
>this might mean that at any given time a galaxy might have 1/1000 chance of
>having ETI. Maybe then on the Hubble frame, or on our past light cone, there
>is on average an ETI on every 1000 galaxies.
The trouble is it's extremely difficult to obtain useful statistics if you only
have one example. On Earth life occurred almost as soon as liquid water could
exist on its surface, but does that mean life is inherently easy to make? Maybe
not because the only example we have is a planet in which not only life
developed but intelligent life did, so life had to have started quickly here,
perhaps freakishly quickly, because if it had taken much longer the sun would
be turning into a red giant about the time intelligent creatures started
building a civilization, and that would make any sort of life on the planet
impossible. And even after life started all you had was simple Prokaryotic
cells, it took another 2 billion years for far more complex Eukaryotic cells to
evolve, and then another 1.5 billion years for multicellular life to evolve,
and 500 million years after that to get a technological civilization which only
happened a few thousand years ago.
How typical is any of this? Nobody knows but we have hints; most major
evolutionary developments, such as the invention of the eye and flight, evolved
independently more than once, sometimes dozens of times but intelligence,
defined as the ability to make a radio, occurred only once. But even when we
look deep into space with enormous telescopes we don't see even the slightest
hint of engineering.
A galaxy dominated by von Neumann probes would like bare some signatures of
such. So far nothing is evident. Of course galaxies we observer are in the
past. We could just be one of the early IGUS or intelligent life forms on the
Hubble frame.
LC
> Now consider there is probably some filter that selects out ETIs. Either they
> annihilate themselves with nuclear explosive, or they collapse the life
> support system of their planet or . , a range of things we may do to
> ourselves that prevents them from ever developing a von Neumann probe.
The human race only needs to hang together for a few more decades before a von
Neumann probe gets made, I don't think it's reasonable to expect that every
single civilization without exception destroys itself just an instant before it
has the ability to make such a thing, especially when you consider that if
intelligence is as common as some claim then some of those civilizations must
have started on planets where the element Uranium is much rarer in its surface
crust than it is on the Earth. On Earth's surface Uranium is not particularly
rare, it's far more common than Gold, but if it was as rare as Osmium, Rhodium
or Iridium we'd have no nuclear weapons today and wouldn't have any in the
future until asteroid mining became practical, and by then making a von Neumann
probe would be practical too.
John K Clark See what's on my new list at Extropolis
swl
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