Fermi Paradox

[Sparhafoc]

I am making a thread about the Fermi Paradox not because I have anything new or interesting to say about the Fermi Paradox, but simply because I love thinking about it and talking about it and hearing new ideas about it... and I'm working under the well-established assumption that 'if you build it they will come', so this is me building it!

Here is where I might insert a cutely packaged anecdote about how the initial formulation was created, but I am not going to - go read Wiki, ya lazy sod!

Instead...

Fermi paradox - Wikipedia

en.wikipedia.org

The Fermi paradox..... is the apparent contradiction between the lack of evidence for extraterrestrial civilizations and various high estimates for their probability (such as some optimistic estimates for the Drake equation).

I include a sentence referring to both Fermi and Drake because it's the Drake Equation and thinking about the factors involved in that formulation which produces the question: where are all the bloody aliens?

You can plug in your own numbers here:

Drake Equation Calculator

A simple online calculator to estimate how many alien civilizations we might be able to contact.

www.spacecentre.nz

Conservative estimates produce anything from 5000 to 20,000 species. It's a good way to make note of some of the core variables involved.


The thing I love about this topic is how well it refines one's thinking. I've seen very smart people become absolutely baffled by their own thought processes here. A great example is actually a component of the Drake Equation itself. We can postulate x number of species as having evolved, got radios, lived 100,000 years and still have died out such a long time ago that there's no overlap between us and them even in radiowaves, or in fact between any of the tens of thousands of notional technological species - each could have lived ion an island of time even if physical space was in their grasp.

I believe the last time I plugged in numbers, I got 5... and thought I was being excessively optimistic.

 

[Deleted member 619]

If Wiki isn't yer thing, there's an alternative source that, in my opinion, treats it quite nicely and in a fun way:

Where Is Everybody?

Now to go back and read.

 

[Deleted member 619]

The thing I love about this topic is how well it refines one's thinking.

I agree. I've seen some pretty muddled stuff about it as well, but I've seen some quite impressive moments of epiphany when people grok the implications of those variables.

I've seen very smart people become absolutely baffled by their own thought processes here. A great example is actually a component of the Drake Equation itself. We can postulate x number of species as having evolved, got radios, lived 100,000 years and still have died out such a long time ago that there's no overlap between us and them even in radiowaves, or in fact between any of the tens of thousands of notional technological species - each could have lived ion an island of time even if physical space was in their grasp.

Aye. The most impressive thing for me about the Drake Equation is that it explains perfectly and completely why the Fermi paradox isn't actually a paradox.

I believe the last time I plugged in numbers, I got 5... and thought I was being excessively optimistic.

When I ran the numbers for my piece, I got 1,200 communicating civilisations in the galaxy. Sounds a lot but, when you distribute them uniformly over the galactic disc (assuming a flat disc, which constrains the distance), you get an average distance of 7,000 light years between communicating civilisations. We've been detecting radio waves for about 80 years.

 

[ldmitruk]

I believe the last time I plugged in numbers, I got 5... and thought I was being excessively optimistic.

The numbers I plugged in return 1080, and I thought I was being conservative. It is an interesting to think about how many civilizations there might be out there. I suspect we will find signs of life eventually, possible within my lifetime. But I don't think it will be intelligent, moist likely bacterial or viral, maybe within our solar system.

 

[Dragan Glas]

Greetings,

We've been detecting radio waves for about 80 years.

And transmitting them for less.

So, it's no wonder we haven't heard from anyone - never mind heard any reply.

Kindest regards,

James

 

[surreptitious75]

The expansion of the Universe through the red shift of galaxies makes it less likely over time that any other life forms will ever be detected
And as we only know of one world where a technologically capable life form has evolved then we have zero idea how accurate the Fermi is
But can we even be absolutely certain that none have never passed the local space within our Solar System and merely carried on their way
Is not fallacious to presume that they would actually want to contact us since their philosophy / psychology may be entirely different to ours

 

[Deleted member 619]

The expansion of the Universe through the red shift of galaxies makes it less likely over time that any other life forms will ever be detected

Not even a little bit. If we ever do detect extraterrestrial life, it will almost certainly be within our own galaxy, which is gravitationally bound and not subject to cosmic expansion, or in a neighbouring galaxy - part of the local cluster - also gravitationally bound.

 

[Sparhafoc]

It's not like we were expecting to have a chat with someone in another galaxy.... well, perhaps if we're still alive in billions of years when Andromeda may well join the Milky Way's party. A trillion or so stars - ya never know!

 

[Dragan Glas]

Greetings,

Just to follow on from my earlier post...

It could be argued that we should have received radio signals from everywhere in this galaxy by now, at least.

For example, if a civilization 1000 light years away had radio, and had been "leaking" signals - rather than actually transmitting them in our direction - then why haven't we detected them now (a thousand years later)?

And similarly for any civilization with radio at any distance.

The likeliest reason is that such signals would be dissipated/destroyed by all the other radiation between them and us.

Kindest regards,

James

 

[Deleted member 619]

Or that they and their signals came and went before we had the tech to detect them.

 

[Sparhafoc]

Or that they and their signals came and went before we had the tech to detect them.

Right, and even if they were producing radio signals a thousand years ago, we'd still need to be relatively lucky today to pick up their signals through pointing our receivers at the right millimetre of sky.

 

[Dragan Glas]

Greetings,

Theoretically, we should be receiving signals all the time from civilizations in all directions at all distances (who had radio at that time), however, due to the fact that cosmic radiation would simply wipe-out such radio signals - even from relatively close by - suggests that it's unlikely we'll be able to detect such signals.

Unless they're beamed intentionally at us from a suitably close distance.

A recent study suggests that there are some 2000+ star systems within 10 parsecs that can detect transiting planets - including Earth - around our sun, If any of those are inhabited, and have radio, we might get a signal.

Kindest regards,

James

 

[Sparhafoc]

Greetings,

Theoretically, we should be receiving signals all the time from civilizations in all directions at all distances (who had radio at that time), however, due to the fact that cosmic radiation would simply wipe-out such radio signals - even from relatively close by - suggests that it's unlikely we'll be able to detect such signals.

I think that first sentence makes a few too many assumptions though.

There's no real reason to believe that we should be receiving detectable radio signals all the time even if the galaxy had been littered with ancient civilixations - the distances involved means that such civilizations would have needed to be emitting radio waves an amount of time relevant to their distance to us, and had continually emitted radio waves prior to and after that in order for those signals to reach us at the right time and be perceivable as intentional emissions. Had a technological civilization a million light years away existed for 100,000 years a billion years ago, then the majority of the radio waves they emitted would have long since radiated past us - perhaps the earliest forms on life were bathed by the emissions of that ancient civilization.

Of course, there will be those electromagnetic signals bouncing around, being deflected and generally affected by gravitational forces that could still plausibly be captured by chance by our receivers... but in turn those signals would be too disparate to be detectable by us as the intentional emissions of a civilization possessing radio technology.

I think you latter point plays into that too - it is a limitation on our technology, but it's hard to imagine easily overcoming these limitations. The wider we cast our net, the less chance we'd have of picking up highly scattered signals, and while the closer and tighter we look/listen the greater chance we'd have of finding any emissions, the galaxy is a big fucking place so each time we increase the zoom we increase the demands on equipment and expert operators by an order of magnitude - while there's some societal/political appetite for searching for extra-terrestrial life, it's nowhere near enough to really feel like we're giving it our best shot.

Unless they're beamed intentionally at us from a suitably close distance.

A recent study suggests that there are some 2000+ star systems within 10 parsecs that can detect transiting planets - including Earth - around our sun, If any of those are inhabited, and have radio, we might get a signal.

We also have to wonder whether radio waves are something that a civilization ends up realizing is not something they want to keep emitting into the universe - just in case.