Back

Detectable Civilizations in our Galaxy 4

⇐ Use this menu to view and help create subtitles for this video in many different languages. You'll probably want to hide YouTube's captions if using these subtitles.

Detectable Civilizations in our Galaxy 4 : Taking a shot at estimating the number of detectable civilizations

相關課程

0 / 750

I have talked a bunch about the Drake equation or our own version of the drake equation
that starts with the number of stars in the galaxy.
But I haven't given it a shot yet
I haven't tried my own attempt at thinking about
how many detectable civilizations there are
So lets actually do that here
so lets just assume there are one hundred billion stars
so that's my first term right over there
lets say that one fourth will develop planets
and lets say of the solar system that develop planets
on average 0.1 are capable of sustaining life
or you will have one planet for every ten of these
solar systems with planets
that's just my assumption there
I don't know if that's right
now lets multiply that times the fraction of these
planets capable of sustaining life that
actually will get life
And I don't know what that is
but I hinted in previous videos that
life is one of those things that it seems as if you have
all the right ingredients it's so robust that you
have life at these underwater volcanoes
you have bacteria that can process all sorts of weird things
so lets say that probability is pretty high
lets say that is fifty percent
or half of the planets capable of getting life
actually do have life
I would guess that might even be higher
but once again
just a guess
now we have to think about
of the life what fraction becomes intelligent
what becomes intelligent over some point in the history
well I will say its a tenth
well maybe if the asteroid didn't kill the dinosaurs
then it wouldn't have happened on earth
or maybe we might just have had very intelligent dinosaurs around
we don't know
so maybe there might be other forms of intelligent
life that we haven't fully appreciated
dolphins are good candidates
some people believe that octopuses
because they have such flexible arms
there's a theory that they could develop eventually
the ability to kind of
one day if their brains mature
and all the rest
make tools the same way primitive primates
eventually were able to have larger brain sizes
and actually manipulate things to make tools
so who knows
I don't want to get into all that
so there's a one in ten chance that you get intelligent life
and then assuming that intelligent life shows up
what fraction is going to become detectable
I don't know
I don't know whether dolphins will ever communicate
via radio or not
so lets just say that is another one in ten chance
or I will say 0.1
and then we have to multiply times the detectable
life of the civilization
on average
once again huge assumptions being made here
but the detectable life of a civilization
let me just put it at ten thousand years
either they destroy themselves
or they go beyond the radio type of communication
electromagnetic type of communication
maybe they start all sorts of weird wacky things
probably won't even take ten thousand years
to even progress at that
might take less time
but lets just do this for the sake of fun
and then the lifespan of your average star
that's probably one of the things that we have the best sense of
so on average lets put it at ten billion years
so lets calculate all of this
lets get my handy TI 85 out
and so we're going to have one hundred billion
thats one times ten to the ninth
sorry no thats one hundred times ten to the ninth
so let me clear it
or you can have one times ten to the eleventh
that is a hundred billion times 0.25
times 0.1 times 0.5 times 0.1 times 0.1 again
times ten thousand divided by ten billion
so times ten thousand divided by ten billion
so thats one "e" ten
one times ten to the tenth power
one with ten zeros
so lets see what we get
we get 12.5
which is kind of a neat number
but you know these are heavily dependent on this
so we'll say that given all these assumptions
there should be 12.5 detectable civilizations
in our galaxy right now
so the questions is why aren't we detecting it
maybe their radio signals or electromagnetic waves
are getting to us but we can't differentiate
it from noise right now
and that's what the SETI project is all about
trying to keep track of all this information
all the radio and electromagnetic waves coming from
outer space and towards earth
and seeing if any of them actually have
any non-noise signal
that actually look like they are being generated
by some type of intelligent civilization
so maybe we are getting them
and just not detecting them
or maybe something else is at play
maybe we have over estimated one of these
maybe there is a lot of life
but maybe they are not using electromagnetic
waves to communicate
maybe that's some sort of primitive way of communicating
maybe they start doing telepathy or something crazy
or they started using some quantum thing
that allows them to communicate more directly without
having to wait for the speed of light
they might view that as a very slow way to communicate
and it is frankly a slow way if your trying to communicate
across solar systems and stars and planets
or even across galaxies one can imagine
so maybe we are in a transition state of communication
that electromagnetic waves
radio and all the rest is just a transition state
maybe in a hundred years we'll figure out another
better way that's not detectable in our traditional ways
maybe we are being bombarded by another type of
communication mechanism which we are not ready
to perceive yet
who knows
but its just a fun thought experiment to just say that
hey given these assumptions there should be at least
a couple of civilizations or a handful of
civilizations that we might be able to detect

載入中...

Detectable Civilizations in our Galaxy 4

Detectable Civilizations in our Galaxy 4 : Taking a shot at estimating the number of detectable civilizations