It's one of the top alien-related puzzlers: Given the vast number of stars out there, and the great age of the universe, if intelligent life other than ourselves exists even very uncommonly ... why haven't we met it yet? Surely, somewhere in the multitudes of other stars, at some remote juncture in the past, some alien …
I, for one, welcome our undiscovered alien overlords,
Aliens! Everywhere! Not!
We simply don't know enough about the universe yet to even guess at what life may be in it. The fact that two theories exist that are polar opposites speaks volumes. We need to do much more research before we can entertain even the notion that there might be alien artifacts in our solar system to find.
Fermi Paradox is very short sighted.
- the vast size of the universe.
- things like warring organisms and self destruction that are sure to take out many advanced civilizations before they can expand to space
- The ethnocentric aspects of life (If a civilization were properly advanced and not using up the resources on their planet that they know and love... why spend so much time to go all over the universe? Really having just a second planet to make destruction of your species less likely would be enough to stop spending so much effort and conquering the whole universe and leaving your mark)
- The immaturity of our species and even looking around our own solar system
Saying there must be nothing out there just because we have launched a few satellites, is like looking out door early in the morning, seeing no one and assuming "oh I must be the only person on Earth"
Stupid very very stupid.
"The ethnocentric aspects of life (If a civilization were properly advanced and not using up the resources on their planet that they know and love... why spend so much time to go all over the universe?..."
It's not about resources, it's about identity.
Despite ample resources on Earth, plenty of people today would want to found their own planet, their own empire, their own "better" civilization for religious, political or other ideological reasons if they could. Maybe even because they can.
You can bet if we as individuals had the technology to survive and travel in space that there would be a constant outflow of ships heading for "the middle of nowhere"
You should play minecraft. Has nothing to do with space but you'll find the reason players spread all over the map has nothing to do with resources and all to do with finding their own space and territory.
As humans we have this drive to see what's just past the edge of our vision or around the next turn. It assumes this same trait in all intelligent life. Perhaps there are civilizations out there thousand of years more advanced than us who, lacking said drive, have yet to even send a manned craft into orbit around their own planet.
"As humans we have this drive to see what's just past the edge of our vision or around the next turn. It assumes this same trait in all intelligent life."
You don't need it in all. You only need it in a few. If even only a few species in the galaxy were like this they would have spread throughout the entire galaxy by now.
It's a fair point, but completely ignores the other likely and easier to spot sign of intelligence which is it's EM emmisions. SETI exists because it's easier to look for ubiquitous evidence than to turn over every stone in the solar system, looking for one small object.
The question remains, why are we not seeing any evidence?
How long does a civilisation radiate EM signals
Possibly a long time, but taking the one example we know (us) our omnidirectional EM output is actually dropping overall as we move to cable transmission, fibre optics, podcasts instead of radio and low strength wi-fi.
Don't forget a Star is a pretty big EM emitter naturally and any source has got to be resolvable with that in the background.
re: EM emissions
I believe EM Emissions from Earth would be very hard to detect in the noise floor at a light year away and becoming harder as technology progresses. 150 years ago we wouldn't have been able to detect one of today's most powerful radio transmitters if it was placed on moon - maybe in before the next 100 years have passed we'll worked out how to (there was a recent idea about seeing their light)
"It depends", of course
There's only been a fairly short period in human history with bloody great omnidirectional high power transmitters spitting out something that clearly looks like a signal. As time goes on, we're moving towards smaller transmitters, complex encoding schemes and stuff like ultra wideband with the result that in the not too distant future Earth simply won't be emitting anything that looks like a carrier wave between DC and gamma rays.
That suggests that in order to find developing technological civilisations you have to be listening very carefully during the hundred year window in which clear signals can be seen. The sort of thing SETI could spot is a deliberate, high powered signal sent by something with the intent to communicate that came to the same conclusion as SETI when deciding on which frequencies to transmit on.
Alternatively, black helicopters, government conspiracies, inhibitor machines, everyone hiding from R-bombs, whatever.
By Chromis Pasqueflower Bowerbird's cube!
"NASA's efforts in putting the famous plaques on them may well be wasted"
Hoping that someone finds these plaques is like hoping that this EXTREMELY IMPORTANT PIECE OF PAPER ON THE TRUTH ABOUT THE SECRET IRANIAN PROGRAM TO BUILD NUKES AND TAKE OVER THE WORLD that I have in front of me and will now throw into the loo will somehow arrive on the desk of POTUS.
Not gonna happen.
One really has to invest a bit more seriously in local marketing efforts.
that's crazy talk
that's crazy talk, you crazy person. Every fule kno the Iranian program to build nukes and take over the world isn't *remotely* secret.
Damn, I was gonna do the "I, for one, welcome..." thing :(
OK - I'll do a TMA-1 thing instead !
What, exactly, are the chances of something like Voyager getting even close to making it to another planet intact? Yes, it's likely to end up in some kind of orbit or some kind of Lagrange point but so is EVERYTHING else, including an awful lot of boring rock.
Not to mention natural decay, corrosion, irradiation, micro-meteorites, etc. smashing the thing to pieces, after a few light years it's going to be unrecognisable junk or it's going to get captured / destroyed by something far larger and heavier. The chances of us recognising a bit of smashed technology once it's been superheated, subjected to extreme pressures, smashed repeated by rocks and other debris, and whizzed a few light years to even the nearest star are almost zero - it'll virtually be a little muddy molten puddle of it's original makeup.
Ignoring the statistics of whether we're likely to find them or not (and this says "unlikely", and we already believe the chances of civilisations even being able to contact others across interstellar scales are so remote as to be effectively zero), when we do find them the chances of them being in any way recognisable, useful, or another other than a pile of mush are really quite slim. Also, sheer scale. If you had an Earth-size planet exhaust its entire metal supplies by launching probes in every direction for thousands of years, chances are that we'd never detect them even if they were the next star to ours.
"What, exactly, are the chances of something like Voyager getting even close to making it to another planet intact? "
Very very very tiny. Small enough to be practically nil, actually, and EVEN THEN, if a Voyager/Pioneer probe does enter into a solar system, it is more likely to be shot out of it in a hyperbolic orbit than to be captured within the system.
natural decay, corrosion, irradiation, micro-meteorites, etc
Decay how? metal eating mould? Interstellar space is a pretty tenuous vacuum. Probes would simply be too far from star systems to run into anything more substantial than the odd hydrogen molecule... certainly no micrometeorites, and radiation from stars would be incredibly tenuous. The only things that could cause corrosion would be its own components, and they seem stable enough... especially in the absense of any heat or light!
You seem to envisage deep space as a busy, hostile sort of place. You're a fair old way from the truth. Voyager can and will reach *somewhere* intact, eventually. The odds of anyone ever finding it are beyond astronomical, of course.
Even if something did come into contact with a planet, the chances are it would be the biggest ones in that system, just like our gas giants have hovered up vast numbers of comets and asteroids. And don't forget about that big old gravity well at the center called a star.
Then there is the fact that such an object would be traveling really - really fast, it's not going to have a soft landing anywhere. If it didn't burn up in an atmosphere it would be nothing but fragments and dust and probably vapor after hitting anything.
I suspect it's very unlikely that either voyager or pioneer will ever just happen to drift into another star system occupied by intelligent life capable of detecting it and determining what it is. The odds are so vanishingly small that this paradox doesn't sound like much of a paradox but common sense.
Also with the human lack of commitment to space why assume ET decided space was the way to go? Unless it was made up of people from the Isle of Man.
Also that isn't many aliens, if only every 1 in a million planets in the "habitable region" of a star system develops intelligent life then that's only about 500 intelligent life forms on latest guesses. So with several hundred billion stars in the galaxy, and all the debris and phenomena, what are the chances of a small unmanned unpowered probe reaching one of those 500 worlds at the right moment in a species existence for them to take notice?
Too many jokes
That's no moon
Hey - what's this large black monolith?
What are all these alien souls doing in this volcano?
I thought everyone knew that Charon is, in fact, a Mass Relay...
Of all the hand waving going on in that series, extra special bonus points for the use of that particular object as a hand wave to explain the circularity of Pluto's orbit in the system map.
That's no moon...
Maybe the whole moon is an alien artefact.
You can imagine what the beachball-shaped inhabitants of Omina Pleidie IV are saying;
"Bloody humankind. We leave this HUGE statue of K'rug, the founder of our glorious civilisation here for you to find, with carefully-placed rock features spelling "WE COME IN PEACE" in 300 of our languages, and you land on the bloody thing, kick our carefully-arranged messages about and plant a stupid flag on K'rug's left eyebrow.
You were supposed to look at the damn thing, not rearrange it. Why do you think we engineered it to show the one face to Earth all the time? Seriously. That's it; we give up."
We may be surrounded by artefacts that we simply do not see, because we do not know how to see them or what we are looking for.
We can only measure things we know how to measure...
Maybe we are the artifacts.
I look in the mirror every morning and think
"God, I look like an alien"
maybe I am jelly
By this logic...
If everyone has a good look around their garden tonight there is a reasonable chance one of us will find an alien probe?
yeaaaah, but also, noooo....
saying "given that they are there, what is the probability of finding them" is not the same as "what is the probability they are there and that we also find them". the universe is very large and we are aware of only a vanishingly small amount of it, so the likelihood of there actually being anything in the bits we can see is thus also vanishingly small. i would argue that your use of "littered" is really rather optimistic, even for the el reg alien hunting desk...
We just haven't climbed enough lunar mountains yet...
I, for one, welcome our purely speculative alien overlords.
There may well be millions of 'advanced civilizations..
but space is BIG, VERY BIG.
Consider if there were 1 million advanced civilizations in the galaxy willing to send probes - they've got a choice of ~4e11 stars to send a probe to. OK they could rule out quite a lot but it's still one very large number of which we are 1. Plus the distance. So we'd be dependant on a civilization developing in our neighbourhood, wanting to send missions, choosing us amongst many, and the probe arriving, not malfunctioning and us spotting it.
and that's just assuming that they ARE out there...
which they may of course not be!
All of these ideas like the Fermi paradox and the Drake equation are ultimately rooted in guesswork and therefore only of academic interest. Drake never intended his equation to be used to determine values - it was intended as a thought exercise, as was Fermi's paradox.
What I was gonna say
It may be that intelligent life is as numerous as grains of sand on a beach, it's just that the beach is SERIOUSLY FUCKING big!
"Consider if there were 1 million advanced civilizations in the galaxy willing to send probes - they've got a choice of ~4e11 stars to send a probe to. OK they could rule out quite a lot but it's still one very large number of which we are 1."
Why do you assume they would only build one probe? Consider probes being able to travel to multiple stars too.
As I said "it's still one very large number ( of targets) of which we are 1."
I assumed they may well send multiple probes it's just that the number of 'local targets' is enormous. I think probes doing 'grand tours' is rather far-fetched and in any case would take a long, long time.
If there is one "advanced" civilization per 100 solar systems, and each of these civilizations puts out 10 000 interstellar probes over it's lifetime, and 1% of these probes happen to find a useful resting place (i.e. not a star) in another solar system, that means on average that there is one extraterrestrial probe somewhere in each solar system. Fancy searching the surface of Jupiter or Saturn? Those are the most likely resting places..
And IMHO, my assumptions are wildly optimistic - assuming 1 civ per 10 000 systems, 1000 interstellar probes, and a 0.1% chance of finding a useful resting place, you get a 0.01% chance of a probe in any one solar system.
And we haven't begun talking about the fact that a probe landing on earth even just a few million years ago would be buried, just like a fossil.
SETI has a much better chance of finding anything IMO... If a civ wanted to show it existed and find other civs, and had the capability, why wouldn't it send out vast numbers of probes, each with a radio sending out messages and some kind of atomic battery to ensure long life.
Modifird SETI, maybe
A modified SETI might work, yes, but modified by what it scans.
I don't think EM is the best thing for it to be looking at, at present. It's such a noisy enviroment in general that its like having a fire alarm at a school being a normal persons voice - it's buried in the surrounding noise.
I'd expect it to be more like a neutrino stream, or some other near- lightspeed (or tachyon) particle, that would stand out, pentaquarks, or maybe a charmed bottom Omega baryon. something *distinctive*
It's why you should be supporting, not SETI@Home, but projects like Muon1 (which is british, and just had it's 70Millionth result Tuesday night)
I see little scientific value in such speculations, as the assumptions made are often rather arbitrary or chosen to support the desired conclusion. (If the calculations don't match expectations, change the assumptions until they do).
The only way the Fermi paradox can be resolved is if hard evidence of alien civilisations are found. Otherwise, there are all sorts of more or less plausible explanations why we haven't found any evidence and it doesn't get us anywhere calculating probabilities some of those -- there will always be other explanations.
"Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
So, effectively, finding a few specific grains of sand amongst an infinite amount of sand.
“It is known that there are an infinte number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Any finite number divided by infinity is as near nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely products of a deranged imagination.”
Very good but
you should really acknowledge that the quote is from Hitchhikers
...and as far as is known, the universe is NOT infinite
it's just very very very very big. These two things are not equivalent. An infinite universe allows an infinite number of worlds, a very very very very big one does not.
This seems to be where all that misguided (almost religious) belief that we can't be alone comes from.
We may be alone. We may not be alone. The question is not answerable because there are too many unknowns.
No, we don't know
That's the whole point, its not known.
We can assume its infinite, or we could assume its not.
Not having seen ANY semblance of an edge or end, I tend to lean towards the theory that it is indeed infinite, but to say it's only really really big implies you've seen the edge, or seem to know the size.
And certainly "as far as we can see" is not an edge, sure theres a point it appears to stop, but so does the land when your out in the ocean far enough. If we travel a million light years across the universe, I bet we will see more of the same in all directions.
Even if what we can see of the universe were all that there was of it I've always felt that chances are there are aliens out there somewhere. Even if our solar system is an oddity and only half the stars we can see have any planets at all and most of those only have one (both of which I think are unlikely scenarios) that's still an awful lot of planets. For this to be the only planet out of a zillion or so to have intelligent life seems extremely unlikely to me.
@Rob Dobs : Yes, we do know
If the big bang theory is correct (and it seems the most likely to be), the universe exploded from a singularity about 13 billion years ago and has been expanding ever since.
That makes it very big, not infinite.
Why do you think it's unlikely? How does life start? How likely is it to start? Of course you have no idea on either count. You have nowhere near enough information to ask the question, let alone guess at the answer.
What you mean when you say "I've always felt" is that you *want to believe*. I'd like to believe it too, but that's not science, it's just pseudo-religion.
Try something a little more scientific : http://hanson.gmu.edu/greatfilter.html
See past El Reg stories
Specifically the one about supposedly universal physical constants not being constant at all. The calculations for the number of alien civilisations all assume that the universe is EXACTLY as friendly to life elsewhere as it is here; if this is not the case, and we are in a spot which is especially nice for life, then the calculations are so much bunk.
The Fermi Paradox isn't just about artifacts
Fermi was pointing out that any civilisation only slightly more advanced than our own should be capable of spreading throughout the galaxy within a timescale << 100 million years (and that's without requiring any warp drives or other fanciful notions). Not all such civilisations would necessarily choose to spread out in this way, but it would only take a single event to populate the galaxy. So why don't we observe them?
I personally like Fermi's own answer: alien intelligences are already on Earth, we just call them Hungarians.
>I personally like Fermi's own answer: alien intelligences are already on Earth, we just call them
Look at those names: Jacob Haqq-Misra and Ravi Kumar Kopparapu. No-one has a name like that (let them try and get a G+ account, see how far they get), so they must be aliens themselves. Although any alien worth its NaCl-equivalent would probably have chosen a more common, inconspicuous name like Ford Prefect.
Wasn't one of the mars rovers tested in a "Mars-pit" where various obviously non-martian objects had been left behind rocks to see if the rover operators would notice them? I recall that it wasn't hugely successful which would suggest that there is some mileage in this theory. After all, Voyager et al will be stone cold dead electrically (and radioactively?) by the time they end up in some other solar system so it really would be like looking for a tiny black artificial object (that may not even be there) amongst billions of similar sized lumps of rock. Odds of spotting it accidentally would be astronomical, odds of spotting it on purpose probably not great either...