The Fermi Paradox - What It Is and Categories

a reply to: HiddenWaters

The answer to your question is: Yah, we would have missed it.

But keep in mind that there are many things that use RF energy, not just radio and TV. Radar system and other communications systems also use RF (Radio Frequencies) energy.

Another idea: 1000 years ago, that system 50 ly away was using radio....then, for whatever reason, they all died out. Again: we'd have missed their RF emissions.

That's the thing I love about this subject: there are just so many ideas to float out there. And they don't have to be "They all died" or "We are alone" either.

originally posted by: eriktheawful
Another idea: 1000 years ago, that system 50 ly away was using radio....then, for whatever reason, they all died out. Again: we'd have missed their RF emissions.

On the other hand, we'd still have at least a small chance of catching the transmissions from all the civilizations from 1,000 ly away who were using radio 1,000 years ago, or 1,500 ly away using it 1,500 years ago, and so on forever. And if there are scads of these civilizations around, our odds of being in just the right spot to pick up these transmissions greatly increases.

So maybe it isn't a matter of broadcast windows and civilizations dying out, since we could have a lot of civilizations broadcasting at essentially all times, it's more a matter of sorting the signals from the noise. What with propagation drop-off, frequency shifts and distortion from speed, and other noisy things in the sky, it's really noisy.

On the other hand, a huge, powerful civilization could form galaxies into words or symbols for us to see throughout space and time. If they wanted to. Or existed.

Maybe we're the only game in town. We beat the odds and got this far, but we're the only ones who ever did it, and maybe ever will. So some civilization a million light years away might pick up our broadcasts a million years from now, when we'll all be dead. Or not. Could be we're all just here and gone and all for nothing. No one will ever know or care about the little creatures that used to run around on Earth for an incredibly short time. The way I understand reality, that seems the most likely.

originally posted by: Blue Shift
Yeah, the biggest problem still seems to be that we're expecting to find aliens that conform to and live within the reality that we have defined for ourselves, given our very limited senses and intelligence. That's just dandy for maybe finding aliens who are like us (so far, no good), but it's not going to help us find or recognize aliens that are way smarter than us, or exist in a kind of reality we just don't have the senses and brains to comprehend.

I don't see that as a problem. Sure, alien life might be so far different from us that we don't recognize it. That's a theoretical possibility, but I'm not sure it is a practical one. Implicit in the Fermi Paradox is the idea that we want to meet these guys and talk to them. If they're a form of jellyfish, that probably won't be easily accomplished. It's really the same issue we discussed above. We're assuming a space-faring species that can get here, not a Renaissance-era civilization in the next galaxy, even though they may be recognizable by us easily. The question on the table is not, "Do they exist?" The question is, "Where is everybody?" (as Fermi expressed it.) In other words, "Why aren't they here?" Of necessity, that limits the set of civilizations you are talking about already. To suggest we may not recognize some species that is far different than we are is to expand the issue rather than refine it.

a reply to: Blue Shift

Your last paragraph goes hand in hand with one of the Rare Earth solutions.

That thread, when I get to it, will be steeped in the evolution of humans.

Which, as Augustus pointed out: when you read through the evolution of humans, it reads like one lucky break after another, tacked on to a set of very special circumstances.

It can be some thought provoking things. I mean, if we include all the possible Earth Like planets in the universe itself, the odds are staggering that it would happen over and over.

But if you limit it to just one galaxy, ours.........the odds are worse than winning the lottery.

originally posted by: eriktheawful
a reply to: AugustusMasonicus

Yah, Rare Earth has two major sub categories:

1) Planets that can have life.

2) Planets that can have life, and it evolves into tool using intelligence.

I'll cover both in different threads.

I remember the look on a friend's face when we were talking about this one day. He stated:

"But every star has a goldilocks zone, it's just in a different place depending on the star."

My response was: "Yah....but not every star always has a planet that formed there in that zone."

The look on his face was priceless, as though it never occurred to him that a star might only have planets too close or too far.

There are SO many different things that can be talked about. Over the years I've been surprised at the lack of discussion on this in any depth here on ATS.

The galaxy itself has a goldilocks zone as well. Life would have a very hard time forming in the crowded area. The radiation in the center of a galaxy would kill off any life. There us a reason we are in the outskirts of our galaxy. We don't get hit with a lot with radiation or gravity from other stars. And we are not in the spiral arms which again would be disruptive.

This means we need a solar system not in the downtown area and not in the spiral arms but between them. This means easily 90 percent of our galaxy is hostile to life. Throw in other conditions and we very well could be the only sentient beings in our galaxy.

a reply to: dragonridr



Yep. You're getting the idea of what the next thread is going to be about.

originally posted by: eriktheawful
It can be some thought provoking things. I mean, if we include all the possible Earth Like planets in the universe itself, the odds are staggering that it would happen over and over.

But if you limit it to just one galaxy, ours.........the odds are worse than winning the lottery.

Yeah, but as I've also said before, maybe there are millions or billions of civilizations out there, but they're just so far away that we'll never have any contact with them or even find the slightest trace of evidence for them, and vice-versa. And in that case, even though they might technically "exist," to us they'll always be hypothetical. Which on a practical level is essentially the same as them being fictional. Can something exist if we don't have any evidence of it -- direct, secondary, inferred, circumstantial?

I haven't read all of the responses, but I feel the OP left out something vital. If it's been hashed over already my apologies.

First a review of the OP's summations:

1) Rare Earth: Planets that can not only sustain life, but develop intelligent life are so rare that most galaxies do not have even one planet like this. This category covers a HUGE range of reasons for this, but does not exclude planets where alien life did develop, just that they did not develop "intelligent tool using" life.
2) They Exist But Do Not Communicate: This category is for solutions that says sure, there are plenty of intelligent aliens out there, but for one reason or another they either do not communicate, or we can not see/hear them.
3) The age of many of these stars are older than our own stars, giving plenty of time for other life to arise.
4) Considering the age of the universe, even if a trip to our planet took millions of years, there has been enough time for them to get here.
5) They Have Existed But Always Kill Themselves Off: this is the Doomsday category, in which the idea is that alien civilizations do develop and advance, but always seem to end up ending themselves one way or another.
6) The Universe Kills Them All Off: This again is another category where they do exist, but the universe is a dangerous place and at some point, every alien civilization's number is up at some point and their luck runs out.

I'd like to add a 7th potential, and I believe most likely answer:
7) They are here, and we are them.

I think the best place to look to discover whether or not there's other colonies of intelligent life is to first see if we are aware of any beings that are capable of interplanetary travel. We don't have to look far, because the human mind is capable of such a feet. If the human brain is capable of it now, then it has always been capable. Sure rocket science is relatively new to us, but the concepts have been around forever. Whose to say we didn't plant ourselves on planet Earth, and many other planets. The fact we can now alter our own genetics, means that there's a chance we have in the past made suitable humans depending on the planets we intended to inhabit and colonize.

So if we wanted to colonize a hot, dry, and oxygen deprived planet we simply splice DNA so that our embryo's grow scales and shed their skin.

But as soon as we placed a man on the moo, as soon as we placed an RC car on Mars, as soon as we "walked in space", we became the best answer as to how we arrived here on planet Earth - us. Not only do I think there's intelligent life elsewhere in the universe, I think there's human life.

originally posted by: Blue Shift

originally posted by: eriktheawful
It can be some thought provoking things. I mean, if we include all the possible Earth Like planets in the universe itself, the odds are staggering that it would happen over and over.

But if you limit it to just one galaxy, ours.........the odds are worse than winning the lottery.

Yeah, but as I've also said before, maybe there are millions or billions of civilizations out there, but they're just so far away that we'll never have any contact with them or even find the slightest trace of evidence for them, and vice-versa. And in that case, even though they might technically "exist," to us they'll always be hypothetical. Which on a practical level is essentially the same as them being fictional. Can something exist if we don't have any evidence of it -- direct, secondary, inferred, circumstantial?

The biggest problem is if only one or two lifeforms in a galaxy the possibility of meeting another goes to near zero. Each galaxy might as well be a separate universe. The distances to cross far exceeds any positivity of traveling between them. There's probably millions of sentient beings but the distance to get here would be insurmountable.

If aliens exist on our planet then they would all ready have to be here. And from our planet

Posting to be able to come back to this thread as soon as i get off work.

Excellent thread thank you to Erik and all who are participating. Old school ats😃

originally posted by: dragonridr
The biggest problem is if only one or two lifeforms in a galaxy the possibility of meeting another goes to near zero.

Because of the size of the universe, statistically speaking, we don't exist.

a reply to: AugustusMasonicus
Um... a chemical reaction?

I find that UpIsNowDown´s first post is "fresh" and out of the box. It´s kind of obvious you´think otherwhise.

Im not a physicist (i wish i where -.-) but i always ask myself if nuclear explosions in space are detectable from outside our solarsystem..

en.m.wikipedia.org...

They leave some artificial particles in space that are not naturaly..

So if they detect this unnatural particles they would know that there is an (dangerous) intelligent species out there..

But like im told ya above, im not a physicist
Personaly i hope its number 4... y they keep us in dark? We r not ready yet.. y? Religion..

originally posted by: GenerationGap
I'd like to add a 7th potential, and I believe most likely answer:
7) They are here, and we are them.

Well, people are always talking about the possibility of building multi-generational ships to travel to other stars. Maybe we already have one, called "Earth." Zooming against the cosmic background radiation at a fairly good clip of 390 kilometers per second. Heading... who knows where? It has taken us so long, we forgot.

If there are galaxies with stars so far away that their light will never reach earth, that's where all the aliens are and we will never ever know for sure.

originally posted by: GenerationGap

7) They are here, and we are them.

Unlikely. The reason is that we have fossil and DNA evidence both, and neither are trivial. The fossil evidence for our gradual evolution is very strong, with many links to other animals on Earth. For example, our DNA is 95% similar to chimpanzees. (Down from a reported 98% earlier. reported here) Fossil evidence is overwhelming back through Homo erectus, and very compelling further back than that. If we were, indeed, "salted" from somewhere else, there would be a clear demarcation between us and all other species on Earth, and that is simply not true.

I think life in the universe is not nearly casual, but planned and wanted by someone.

a reply to: GenerationGap

Yes, that category was mentioned in my OP:

4) They Are Here and Do Exist: This is where most of the conspiracy theorist will thrive, that they are here, meddling with us humans, but we're too stupid to notice, or it's been hidden too well from us.

They hypothesis of "we are them" falls under this category.

originally posted by: Vratyas
Im not a physicist (i wish i where -.-) but i always ask myself if nuclear explosions in space are detectable from outside our solarsystem..

en.m.wikipedia.org...

They leave some artificial particles in space that are not naturaly..

So if they detect this unnatural particles they would know that there is a (dangerous) intelligent species out there..

But like im told ya above, im not a physicist

Any nuclear blast would be masked by our sun. It's producing neutrinos alpha beta particles etc. You couldn't detect a nuclear blast even within our own solar system.

a reply to: dragonridr

Of course "we" can. Not pinpointing the location but we definitly can, as in the technology is there and the tools in space, also.

Edit: Of course there will always be circumstances where high energy fission could go undetected.