Fermi Paradox (are we alone?)

reply to post by stormbringer1701


First, there's almost no solid connection or even much evidence that 'UFOs' are related to, connected with, piloted by non-terrestrials.

Second, define ''are we alone'. In this galaxy, at this time, we are most probably the only sentient life. Are there other sentient forms in the entire Universe? Most probably, at one time or another.

reply to post by dogsoldier

This is an important paper that shouldn't be overlooked with this discussion. The gist of it is that we need actual confirmation of life existing somewhere other than earth before any calculation can be done. I know of no statistical method where you can determine the probability of something with a sample size of exactly one. I believe that this is correct mathematically but it doesn't make sense intuitively. I think we all agree life exists out there.

Probability of ET Life Arbitrarily Small, Say Astrobiologists

The Drake equation is one of those rare mathematical beasts that has leaked into the public consciousness. It estimates the number of extraterrestrial civilisations that we might be able to detect today or in the near future.

The equation was devised by Frank Drake at the University of California, Santa Cruz in 1960. He attempted to quantify the number by asking what fraction of stars have planets, what fraction of these might be habitable, then the fraction of these on which life actually evolves and the fraction of these on which life becomes intelligent and so on.

Many of these numbers are little more than wild guesses. For example, the number of ET civilisations we can detect now is hugely sensitive to the fraction that destroy themselves with their own technology, through nuclear war for example. Obviously we have no way of knowing this figure.

Nevertheless, many scientists have attempted to come up with a figure with estimates ranging from a handful of ET civilisations to tens of thousands of them.

Of the many uncertainties in the Drake equation, one term is traditionally thought of as relatively reliable. That is the probability of life emerging on a planet in a habitable zone. On Earth, life arose about 3.8 billion years ago, just a few million years after the planet had cooled sufficiently to allow it.

Astrobiologists naturally argue that because life arose so quickly here, it must be pretty likely to emerge in other places where conditions allow.

Today, David Spiegel at Princeton University and Edwin Turner at the University of Tokyo say this thinking is wrong. They’ve used an entirely different kind of thinking, called Bayesian reasoning, to show that the emergence of life on Earth is consistent with life being arbitrarily rare in the universe.

At first sight, that seems rather counterintuitive. But if Bayesian reasoning tells us anything, it’s that we can easily fool ourselves into thinking things are far more likely than they really are.

Spiegel and Turner point out that our thinking about the origin of life is heavily biased by the fact that we’re here to observe it. They point out that it’s taken about 3.5 billion years for intelligent life to evolve on Earth.

So the only way that enough time could have elapsed for us to have evolved is if life emerged very quickly. And that’s a bias that is entirely independent of the actual probability of life emerging on a habitable planet.

“In other words, if evolution requires 3.5 Gyr for life to evolve from the simplest forms to sentient, questioning beings, then we had to find ourselves on a planet on which life arose relatively early, regardless of the value of [the probability of life developing in a unit time],” say Spiegel and Turner. #

When you strip out that bias, it turns out that the actual probability of life emerging is consistent with life being arbitrarily rare. In other words, the fact that life emerged at least once on Earth is entirely consistent with it only having happened here.

So we could be alone, after all.

That’s a sobering argument. It’s easy to be fooled by the evidence of our own existence. What Speigel and Turner have shown is the true mathematical value of this evidence.

Of course, that doesn’t mean that we are alone; only that the evidence can’t tell us otherwise.

And if the evidence changes then so to will the probabilities that we can infer from it.

There are two ways of finding new evidence. The first is to look for signs of life on other planets, perhaps using biogenic markers in their atmospheres. The capability to do begin this work on planets around other stars should be with us in the next few years.

The second is closer to home. If we find evidence that life emerged independently more than once on Earth, then this would be a good reason to change the figures.

Either way, this debate is set to become a major issue in science in the next few years. That’s something to look forward to.

arxiv.org...
Bayesian analysis of the astrobiological implications of life's early emergence on Earth

The Fermi Paradox is complete and utter BS.

Just because we don't see something, doesn't mean it isn't there.

The paradox only exists if we assume we are able to see everything out there, which we cannot.

Some show had a woman with an excellent comparison. If you went to the beach, dipped your hand in the ocean, would it be safe to say the ocean is devoid of life because you didn't pull up a fish? Absolutely not. Only a fool would assume that.

And only a fool would assume "if they are out there, we should have seen them"

Says who? Maybe we have seen them, and didn't know it? Maybe they are hiding? Maybe they are just far away? Maybe they don't care about us in the least, and have absolutely no reason whatsoever for making their presence known to us?

It's just another example of typical human arrogance, thinking we WOULD see it, just because it's there. We're humans after all, we see everything, right?

The fermi paradox should be a complete non-issue, I have no idea why it's still brought up by any scientists or anybody else for that matter.

dogsoldier
Why is there no convincing evidence of such visits?

If they can interstellar travel, erase memories after abducting ppl etc. they probably can cover their tracks quite well. Doesn't mean they're infallible of course.

So we're back to square one.

I think some people are forgetting just how insanely, mind-bogglingly vast space actually is. The Milky Way galaxy is 100,000 light years across, and contains hundreds of billions of stars (and quite possibly hundreds of billions of planets too).

And that is just one of maybe 170 billion galaxies in the observable universe.

How much of that space have we (or indeed can we) actually looked at closely enough to be able to tell if there's anyone there? Minuscule fractions of one percent.

My own opinion, just based on the probabilities, is that there must be billions of other life forms evolving, living and dying out across the universe, but the distances between them are so vast that contact between them is extremely unlikely.

In order to make interstellar contact, a species has to develop the technology to travel such long distances, which is almost certainly going to include mastering nuclear technology, and quite possibly some hitherto-untapped (by us) even more powerful energy source. If our own species is anything to go by, that comes with quite a high risk that it will annihilate itself using the vast power that comes with such technology.

And that's not even counting the numerous natural disasters that can kill off a species before it has a chance to develop interstellar capabilities. So even if life itself is pretty common, life that can communicate across the vastness of space would probably still be relatively rare. And with the timescales such as they are, the chances that two "neighbouring" civilisations of this type happen to exist at the same brief instant in history and can "overlap" is pretty vanishingly small.


But I'm sure we are not alone. As Carl Sagan said, if it's just us, that seems like an awful waste of space.

You gotta figure, we're only 400 years or so old, modern technology speeking. And look how far we've came. The first controled and sustained heavier than air flight was in 1903, and now we have stealth aircraft. We humans are still in diapers, other civilizations can be a million years ahead of us. What we percieve as the Laws of the Universe will be irrevalent to them. Our understanding of everything may as well be compaired to how a blade of grass look at us, any real scientist that puts any thought into that will agree. I have talked to a couple who are also University Professors who feel the same way. The Earth was also once flat, occording to the Church. I feel other advanced civilizations have no issue visiting us, we just can't comprehend the physics involved, yet. As for wormholes, they very well could be electro magnetic, NASA has three satillites stationed at three magnetic anomolies between the Earth and the Sun to take readings. They don't know just what to make of them yet, but they know they are there. Every month NASA is finding more and more planets, but yet have only looked at a section of sky no bigger than a glass of water, and now saying planets are more common than stars. I'd bet my life that they will find a few dozen in the Milky Way given half a chance. Read some astronomy mags and web sites, get yourselves a good telescope, don't be afraid to spend a grand on something that will turn into a great hobby and at the same time open your mind. You may just see something through that telescope that will blow your mind, I know of a few astronomers who have had that happen to them. And they never believed in UFOs or intelegent life past this planet.

There are an incredible array of circumstances that must align in an improbably specific way for the genesis of life in the (only) method we are familiar with. With that said, the sheer multitude of star systems and galaxies in the universe helps to mitigate the seemingly insurmountable odds AGAINST the formation of life. If even .01% of planets held life, that would still amount to a very large number of inhabited planets. I'd bet the farm that we are not alone.

The question complicates when one factors in time. The universe exists on a scale of billions of years. Humans exist on a scale of thousands. What % of all the species that ever lived existed millions or billions of years in the past, and what % of them evolved to a point where they're capable of preventing their own extinction and thus becoming functionally immortal as a species? Will we be the first?

The reason I postulate we MAY be the first (in our galaxy) is because we, as a species, are on our way to immortality both through biotechnology and robotics. And we'll have achieved this on a timescale, again, in the thousands of years rather than millions or billions. With the continued exponential acceleration our collective technological prowess, within a hundred thousand years we could be on our way to being a type 3 civilization fully utilizing all the resources in our galaxy. At some point, individual humans will become immortal, our procreation and proliferation will greatly accelerate, and we will be sending self-replicating drones to every corner of the galaxy to colonize and extract resources. This again will all be done on a timescale that is insignificant on the time scale of the universe, even if it takes us a million years to reach this point, which it won't. What I'm getting at: In the billions of years our universe has existed, assuming that our path of evolution is "average" in development milestones, where are all the type 3 civilizations? One must not exist in our galaxy, or we're still yet somehow unable to detect that massive energy drain that would be occurring.

This either means most species extinguish before they reach omnipotence (which is foreboding for us humans), or we're exceedingly rare.

And the truth is, noone is giving humans enough credit for what we've figured out about ourselves and the universe. For all we know, we could be amongst the most technologically advanced species out there. The problem is that nobody wants to think this way because it's not romantic. We want very desperately to see ourselves as a fledgling species amongst a great cosmic megaopolis as we've been conditioned by years of great sci-fi that portrays the universe in such a way. While I'm including myself in that desire, I can't let it blind my ability to think rationally about what may or may not be our place in the galaxy, if not universe.

FrankenCub
You gotta figure, we're only 400 years or so old, modern technology speeking. And look how far we've came. The first controled and sustained heavier than air flight was in 1903, and now we have stealth aircraft. We humans are still in diapers, other civilizations can be a million years ahead of us. What we percieve as the Laws of the Universe will be irrevalent to them. Our understanding of everything may as well be compaired to how a blade of grass look at us, any real scientist that puts any thought into that will agree. I have talked to a couple who are also University Professors who feel the same way. The Earth was also once flat, occording to the Church. I feel other advanced civilizations have no issue visiting us, we just can't comprehend the physics involved, yet. As for wormholes, they very well could be electro magnetic, NASA has three satillites stationed at three magnetic anomolies between the Earth and the Sun to take readings. They don't know just what to make of them yet, but they know they are there. Every month NASA is finding more and more planets, but yet have only looked at a section of sky no bigger than a glass of water, and now saying planets are more common than stars. I'd bet my life that they will find a few dozen in the Milky Way given half a chance. Read some astronomy mags and web sites, get yourselves a good telescope, don't be afraid to spend a grand on something that will turn into a great hobby and at the same time open your mind. You may just see something through that telescope that will blow your mind, I know of a few astronomers who have had that happen to them. And they never believed in UFOs or intelegent life past this planet.

I take a somewhat contrarian stance. I think we greatly underestimate our own prowess as a species. We have quantum understanding. We have nuclear technology. This could be at the high end of what is considered advanced by galactic standard. I find it far more probable that most alien life in this galaxy is on the level of the Navi from Avatar.

SaosinEngaged

FrankenCub
You gotta figure, we're only 400 years or so old, modern technology speeking. And look how far we've came. The first controled and sustained heavier than air flight was in 1903, and now we have stealth aircraft. We humans are still in diapers, other civilizations can be a million years ahead of us. What we percieve as the Laws of the Universe will be irrevalent to them. Our understanding of everything may as well be compaired to how a blade of grass look at us, any real scientist that puts any thought into that will agree. I have talked to a couple who are also University Professors who feel the same way. The Earth was also once flat, occording to the Church. I feel other advanced civilizations have no issue visiting us, we just can't comprehend the physics involved, yet. As for wormholes, they very well could be electro magnetic, NASA has three satillites stationed at three magnetic anomolies between the Earth and the Sun to take readings. They don't know just what to make of them yet, but they know they are there. Every month NASA is finding more and more planets, but yet have only looked at a section of sky no bigger than a glass of water, and now saying planets are more common than stars. I'd bet my life that they will find a few dozen in the Milky Way given half a chance. Read some astronomy mags and web sites, get yourselves a good telescope, don't be afraid to spend a grand on something that will turn into a great hobby and at the same time open your mind. You may just see something through that telescope that will blow your mind, I know of a few astronomers who have had that happen to them. And they never believed in UFOs or intelegent life past this planet.

I take a somewhat contrarian stance. I think we greatly underestimate our own prowess as a species. We have quantum understanding. We have nuclear technology. This could be at the high end of what is considered advanced by galactic standard. I find it far more probable that most alien life in this galaxy is on the level of the Navi from Avatar.

Even with an underestimated prowess of ourselves, we would also underestimate other civilizations. Our understanding of Quantum Physics that we do have is infantile, it changes on a yearly basis as we come to grasp more of what we questioned. Our understanding will be much different 5 years from now, even more so 50 years from now. As for our nuclear fission technology, it's dirty and dangerous and every scientist knows it, but we use it until we can fully utilize nuclear fusion and get it to work full scale we still aren't gaining much. Then there's anti matter, when we finally figure out how to safely utilize that the whole Universe could very well be our playground.
It's very probable that many civlizations would be compairable to the 'Navi', which I don't see a problem with that, they are much better off than we. Still, with the emense age of the Universe, I feel there will be many that have technology that we couldn't dream of even in science fiction.

James1982
The Fermi Paradox is complete and utter BS.

Just because we don't see something, doesn't mean it isn't there.

The paradox only exists if we assume we are able to see everything out there, which we cannot.

Some show had a woman with an excellent comparison. If you went to the beach, dipped your hand in the ocean, would it be safe to say the ocean is devoid of life because you didn't pull up a fish? Absolutely not. Only a fool would assume that.

You seem to be under the impression that the Fermi Paradox suggests that the universe is devoid of life. That's not what it says.

with regards to the fermi paradox; how about this? the reason we might not catch a signal is the aliens expect any receiving civilization to be advanced enough to receive a milliwatt signal across a distance of tens of light years.

of course to do that you need a radio telescope at a stellar lensing distance from the sun. otherwise the signal will be too weak for anyone to detect and the data bit error rate will be above 50 percent.

why a society that doesn't not have that may be asking why they haven't received any signals...you know; even evoke some sort of silly but important sounding scientific paradox to claim they have received no signals because there are no signals and no one to send them instead of even having the self knowledge to realize that they lack the skills to receive what is transmitted.

www.space.com...

citeseerx.ist.psu.edu...