Question Why We Haven’t Met Any Aliens Yet?

[arturo.v.dominguez@gmail.]

Do you ask your food what it thinks before you eat it?

Wait what!! ...is the invasion of the purple people eaters upon us?

 

[Classical Motion]

It always gets worse. Worse is constantly re-defined. It grows.

 

[arturo.v.dominguez@gmail.]

Ok here we have what I can only attribute to an old commercial: is it real or is it Memorex. After reading the article it’s hard for me to see it as anything other than an attempt to show, that for anyone to imagine, the existence of other life forms out there is preposterous.

 

[arturo.v.dominguez@gmail.]

Is it alright if I reject these three hypothesis out of hand. Ok while I am of the mind that we cannot possibly be the only intelligent life to be, found in the entire Universe (let alone if there is such a thing as multi-verses). The vastness of just our galaxy, the Milky Way makes it improbable, even just statistically wise, for that to be true.


While I am not saying that our galaxy itself is teaming with extra-terrestrials. When we consider the estimated size of the Milky Way, for us to be the only ones in this our galaxy. I would say that is highly unlikely. Extrapolate that out to the Universe as a whole and well I think at the very least those prospects, being true, are much harder to reconcile.


Heck here is an easy press to test on at least one of the reasons some give as to why there are no other intelligent life forms out there. Well, we should know that (have discovered, or found proof of, one) by now, as being proof of that. If you were to meet up with a person, out in the street, who had never heard of Schrödinger and you asked him/her whether the cat was alive or dead; chances are just as good that they would say, or at the very least think, how do I know there is even a cat in there.


Now as for why I can’t buy into the other two well that’s easy you’re talking about creationism (the ability to create (I suppose out of nothing) in the first one and the self-perpetuating immortality(?) in the second one.

 

[spacedweller]

I humbly suggest that the biggest and only reason we have yet to have found proof and or met aliens whether human in appearance or not. Is because we are just not ready, or rather they know we are just not ready.

Agree, and one possible explanation on how they might achieve this is by having a stealth technology so advanced we're unable to detect them or any of their signals.

 

[ChrisA]

We can observe a very large volume of the cosmos. And we can observe a very long time span of the cosmos, much longer than our MW span, supposedly.

And we have not detected one synthesized signal.

And we know from life here, that life is very tenacious. If life came from the cosmos, it would be all over the place.

But all evidence demonstrates that we are singular and unique. The only singularity ever found.

I suspect that life itself might be common in places where it is possible, but multicellular life is uncommon and intelligent life is VERY rare. The evidence for this is that if you photo-copied Earth once every day for the last 4.5 billion years and scattered the copies randomly you would observe exactly the above distribution, trillions of those copies would have microscopic live and relatively few would have plants and only a very few humans.

So if we assume Earth is nothing special then we'd expect plants with microscopic life to vastly outnumber planits with complex life.

This distribution would mean we might be the only intelligent life in our galaxy but there might be others farther away.
What happens if we do receive a signal from one of them? Far from nothing. They would likely send a beacon and under it data. We would learn a lot from the data, so much that civilization would be transformed.

 

[Classical Motion]

Only if you believe in the modern theory, the modern supposition, of how life started on earth. This right there will limit most research on it. And most concepts of it.

Today’s science is confirmation science. Not exploratory science. They all believe they’re close to reality. A snare they can’t escape.

The modern supposition is that life evolved from a single source, whether that source batched itself here, or was seeded here from a foreign source. And then all the others evolved from that single source. DNA based life.

I don’t think that is possible with life. For me, it’s a much higher probability that life started out as a blanket. Many forms were laid down at once. Life has to have other life to continue. Life is a huge interconnected system. It will take a lot more than a comet to seed it.

Life mitigates and modulates physics. Life selects physics. Molecular choice.

Everyone is looking for a way to break physics and star travel. Life broke physics long, long ago.

Man can only live by breaking physics, using tools, to gather the resources he needs. We are the only life from that advantages physics. That’s what the function of a tool is. And only the proper tool will show us how to understand and measure light. We have no such tool.

We need a light tool. We need to look at light. For we have been blinded by it.

Spacetime is the false path, not the BB or space expansion. For both are products of it.

 

[Rithwik Panka]

I feel like the Rare Earth hypothesis is the most realistic one as single cell microorganism's can form and exist in a quite a few planets we've found (some in our solar system it's self) but then evolving into Intelligent life is where the organisms have trouble evolving into.

 

[Catastrophe]

Why We Haven’t Met Any Aliens Yet? ​

OP has made a good start in answering his own question.
However, more distinction can be made between "met" and "heard from".
To start with, "met" requires both the time for our signal to be seen, and, then, the time for aliens to reach us. Responding to random signals from aliens is a separate issue.

For the first part, how far our signals (if any have been suitable) will retain sufficient power to be receivable at great distances depends on the wattage of the transmitter.

Think of a radio signal like the light from a light bulb, if you focus the light using a specially curved mirror it concentrates it and makes it far brighter within the narrow beam. If you use a nearly perfect reflector to focus the light into a very narrow diameter beam, that light can travel vast distances and still be bright. Similarly, a 20 watt radio signal that is focused using a dish reflector can travel vast distances and be strong, within the concentrated beam spot, but very weak outside the beam. This narrow radio beam must be precisely aimed at the receiver on earth to be strong and low in noise. At the receiving end, a similar dish antenna can receive the signal with only minor losses if it is pointed at the transmitting antenna. This is how a 20 watt radio signal can travel from the moon to earth and still be of high quality.

Source: Mike Azeka.

The power of any omnidirectional signal must be of sufficient power to reach us. Very powerful, unless the signal is aimed exactly at us (very unlikely). Perhaps someone more knowledgeable than I, in these matters, can tell how strong an omnidirectional signal would need to be to reach us across light years in sufficient power?
But first, I do not believe that omnidirectiinal signals from Earth have had time to reach very far, bearing in mind the (receiving) power of our Earth-centred signals in barely 100 years. (Most early ones were presumably very weak?).

Then we have to understand any signal we might receive. How do we reply to what might be static, a type of morse, or what might appear to be gibberish?

To reply to the "heard from" option, The reply to the possibility of our "receiving" an alien message is effectively the same as in the other direction. Any 'civilisation' sufficiently advanced to receive very distant messages would probably not distinguish them from "some foreign language" or, perhaps more likely, from "random noise".

Of course, "meeting up with" must allow time for the theoretical aliens to get here, even if they felt so inclined. Bearing in mind the above points, why would they want to "just come here" anyway.

No, I would not be at all surprised if we did not hear from aliens for decades, or even centuries.

The only caveat I might make, is if large numbers of highly advanced beings are investing lifetimes and are already travelling around our galaxy. I won't assume FTL travel any time soon!

Cat

 

[Greenlight]

I think maybe we are the aliens,

if evolution is true i don't see our bare skin as the best adaptation during an ice age.
we obviously didn't evolve here.

 

[billslugg]

Body hair can be a problem at far northern latitudes where vitamin D production in the skin is limited by low amounts of sunlight during the winter. It can be an advantage where the Sun is overhead all the time. Skin color also varies by latitude. Hairy/bare or white/black. Depends where you live.

 

[Atlan0001]

Body hair can be a problem at far northern latitudes where vitamin D production in the skin is limited by low amounts of sunlight during the winter. It can be an advantage where the Sun is overhead all the time. Skin color also varies by latitude. Hairy/bare or white/black. Depends where you live.

You got it backwards, bill. Hairy, wooly (as in mammoths), thick skinned, in cold latitudes to help retain heat and energy. Hairless, thin furred, thin skinned, fuzzy, in hotter, more sunlit, climates to shed heat and energy.

 

[Greenlight]

Body hair can be a problem at far northern latitudes where vitamin D production in the skin is limited by low amounts of sunlight during the winter. It can be an advantage where the Sun is overhead all the time. Skin color also varies by latitude. Hairy/bare or white/black. Depends where you live.

​

Vitamin D(3) synthesis in the entire skin surface of dairy cows despite hair coverage​

Vitamin D(3) synthesis in the entire skin surface of dairy cows despite hair coverage - PubMed

How hair-coated animals such as dairy cows synthesize endogenous vitamin D(3) during exposure to summer sunlight has been unclear since vitamin D(3) and its relation to sunlight was discovered. The fur of fur-bearing animals is thought to be comparable to clothing in humans, which prevents...

pubmed.ncbi.nlm.nih.gov

i'm still going with we are aliens.

 

[billslugg]

Polar bears turned their hair into fiber optics that transmit UV-B to their skin. This proves that bears are smarter than the average human.

 

[Rithwik Panka]

Body hair can be a problem at far northern latitudes where vitamin D production in the skin is limited by low amounts of sunlight during the winter. It can be an advantage where the Sun is overhead all the time. Skin color also varies by latitude. Hairy/bare or white/black. Depends where you live.

In that case Intelligent life would still evolve from places near the equator with more sunlight and expand across their planet right?

 

[billslugg]

Life will develop under certain conditions. One thing that is required is some energetic photons or particles stirring the mix of chemicals. These packets of energy are what makes things happen. But with every knife there are two edges. If you have too much of a good thing it can destroy what it created. High energy photons and particles cause mutations. Some is good. Too much is bad. Near the equator we will find humans with very dark skin to protect them from UV. Up in Scandinavia we will find people with very light skin. In North America, the far north peoples are Inuit. They have very dark skin but they eat a lot of sea creature organs.

 

[Atlan0001]

Life will develop under certain conditions. One thing that is required is some energetic photons or particles stirring the mix of chemicals. These packets of energy are what makes things happen. But with every knife there are two edges. If you have too much of a good thing it can destroy what it created. High energy photons and particles cause mutations. Some is good. Too much is bad. Near the equator we will find humans with very dark skin to protect them from UV. Up in Scandinavia we will find people with very light skin. In North America, the far north peoples are Inuit. They have very dark skin but they eat a lot of sea creature organs.

"Too much of a good thing!" ((+1) (-1)) = 1/0.

 

[Catastrophe]

I have subsequently found this, which is very relevant

Arecibo message - Wikipedia

en.wikipedia.org

Strangely, it is elsewhere described as 20 trillion watt, omni-directional.

The emission was equivalent to a 20 trillion watt omnidirectional broadcast, and would be detectable by a SETI experiment just about anywhere in the galaxy, assuming a receiving antenna similar in size to Arecibo's.

Cat

 

[ZZTOP]

15 Theories on Why We Haven’t Met Any Aliens Yet

• Interstellar Distance: This suggests that even if intelligent life is common, interstellar distances are so vast that spacefaring civilizations are simply too far apart to have found each other yet. Our galaxy alone is 100,000 light-years across. >>>while interesting it also suggest that no civilization out there has, or could have, advanced beyond us.
• Lack of interest: Some propose that advanced civilizations may not view contact with us as worthwhile. They may be indifferent, focused inwardly, or consider us too primitive to interact with. From their view, we may not seem significant enough to initiate contact. >>>funny yes …insulting to be sure.
• The communications Gap Hypothesis: This theory suggests that we might be using the wrong methods or technologies to communicate with extraterrestrial civilizations. They might be using a form of communication that we haven’t discovered or understood yet. If this is true, we might be missing signals or messages from them because we don’t know what to look for. >>>also, interesting but in its own way still in line with a conclusion that can be drawn from #1.
• Rare Earth Hypothesis: This hypothesis suggests that the conditions necessary for life—especially intelligent life—are incredibly rare in the universe. It’s not just about having a planet in the habitable zone, but also about many other factors, such as having a stable star, a planet with a magnetic field to protect from harmful solar radiation, and the right mix of elements. This would mean that life, particularly intelligent life, is exceptionally rare, making our existence quite extraordinary. >>>well let’s face it this is self-sustaining and, in a sense, expands on the long-held idea that earth is the center of the universe type belief.
• The Great Filter: The Great Filter hypothesis proposes that there’s a barrier or filter that prevents civilizations from progressing to the point of widespread space colonization. This could be anything from a natural disaster, like an asteroid impact or gamma-ray burst, to self-inflicted destruction through nuclear war or ecological disaster. If this is true, it could mean that humanity has a significant hurdle in our future that we’ll need to overcome to avoid extinction. >>>wow a self-fulling prophecy …unless and until it is actually proven wrong it is always right.
• Zoo Hypothesis: The Zoo Hypothesis suggests that there are advanced civilizations out there, but they’re avoiding contact with us. Like zookeepers observing animals, these civilizations might be watching us from a distance, allowing us to live and evolve without interference. If this is true, it could explain why we haven’t had contact with extraterrestrial life despite the vastness of the universe. >>>let’s face it this one while more than just a little bit insulting may actually have a little basis in truth.
• Transcension Hypothesis: The Transcension Hypothesis proposes that advanced civilizations invariably leave our universe. They might create and move to a simulated universe, ascend to a higher plane of existence, or something similar. This would mean that these civilizations are not extinct or avoiding us, but simply exist in a realm that we’re currently unable to perceive or interact with. >>> Oh, wow talk about delusions of grandeur …humans will one day attain the status of gods??
• The Simulation Hypothesis: This hypothesis suggests that we’re living in a simulation, and the aliens are the ones running the simulation. In this scenario, we haven’t met them because they’re outside the simulation and choose not to enter it. This theory raises philosophical questions about reality and our perception of the universe. >>> if you can’t explain it all than it’s just because its not real?
• They’re Already Here: Some people believe that aliens have already visited or are living among us, and that this is being covered up by governments around the world. Evidence for this theory is largely anecdotal and not widely accepted by the scientific community. However, if true, it would mean that we’re not alone in the universe and that our first contact with extraterrestrial life has already occurred. >>>personally, I like this one.
• Self-Destruction: This is a darker hypothesis suggesting that once civilizations reach a certain level of technological advancement, they inevitably destroy themselves. This could occur through means such as nuclear war, ecological disaster, or a poorly controlled artificial intelligence. If this is true, it serves as a warning for humanity to be cautious as we continue to advance technologically. >>> umm a narrowing of # 5?
• The Planetarium: This theory suggests that we live in a simulation, or an artificial environment created by a higher intelligence. They control what we observe and can manipulate our understanding of the universe, making it seem as though we are alone. If this is true, our understanding of the universe and our place in it could be fundamentally flawed. >>> again, a narrowing of a hypothesis # 8?
• The Berserker: This theory suggests that an advanced alien civilization has created self-replicating probes (berserkers) that destroy other life-forming civilizations to prevent potential competition. If this is true, it could mean that we’re in a universe filled with predatory civilizations, and we might need to be cautious about attracting attention to ourselves. >>> I like this one too …we haven’t become quite as bad as we will eventually become …at which point we might have achieved gladiator status for the entertainment of our creator(s)?
• The Gaian Bottleneck: This hypothesis suggests that it’s difficult for life to evolve past the single-cell stage due to harsh conditions on young planets, making complex life rare. If this is true, it would mean that while simple life might be common in the universe, complex life like plants and animals (and intelligent life) is exceptionally rare. >>>A slightly different but also in line with a different Hypothesis # 5.
• The Resource Exhaustion: This theory proposes that civilizations might wipe themselves out through over-consumption of their planet’s resources before they get a chance to become space-faring civilizations. If this is true, it serves as a warning for humanity to manage our resources carefully to avoid a similar fate. >>>what can I say I like this one which although it is in its own sense a re-aiming of # 5 …because it does emphasize my point as to why we should move beyond our home planet.
• The Panspermia: This theory suggests that life is spread throughout the universe by asteroids, comets, and other celestial bodies. It implies that life on Earth could have originated elsewhere in the universe. If this is true, it would mean that life is not unique to Earth and could exist wherever the conditions are right. >>>not sure why this one would be a part of an explanation as to Why We Haven’t Met Any Aliens Yet.

So, if you may allow me to replace # 15 with my own.

The Alien, Human vs Hunam, Alien Paradox Hypothesis _ I humbly suggest that the biggest and only reason we have yet to have found proof and or met aliens whether human in appearance or not. Is because we are just not ready, or rather they know we are just not ready. If a civilization were in fact capable of traversing (i.e. traveling between and throughout the universe) galaxies; I would have to conclude that they have advanced enough to see and recognize where any civilization they happen to encounter is in the rational ability to accept, let alone live with, that kind of reality. In essence where, making contact, before that concept of rationality is present might lead to unwanted outcomes.

We are aliens, unless you believe that nothing created everything because nothing got bored at being nothing then created DNA from as said nothing

 

[arturo.v.dominguez@gmail.]

We are aliens, unless you believe that nothing created everything because nothing got bored at being nothing then created DNA from as said nothing

I can’t but agree with you: the alien’s alien is an alien. Of course, with improbability being the operative word these days. We either need to provide a whole new glossary of terms defined to what we mean when we’re discussing, space, the universe, and/or it’s age. Or we need to decide that we know what we think we know, but in the end it has only as much meaning as what someone else will apply/accept to/of it.

 

[Catastrophe]

I can’t but agree with you: the alien’s alien is an alien. Of course, with improbability being the operative word these days. We either need to provide a whole new glossary of terms defined to what we mean when we’re discussing, space, the universe, and/or it’s age. Or we need to decide that we know what we think we know, but in the end it has only as much meaning as what someone else will apply/accept to/of it.

The map is not the territory. The words are not the reality they purport to describe.

Cat

 

[Catastrophe]

Further to my post #93, I have come across some further points to augment the above.
These are from Science Focus, Vol 16, 2019, page 31. My notes. Not my points.

1. Could we decode (alien signals)? We have only been sending relevant signals for around 80 years, mostly relatively powered - and all analogue. We are now switching to digital signals, which are much easier to detect, but only if the encoding system is known - otherwise they could easily be mistaken for background static.

2. Could we understand it? Although the Arecibo message contains very relevant information (counting structure, DNA info, etc., it is cryptic and maybe difficult for other humans to understand. A corresponding alien message might be very difficult for us to understand.

3. Are they still there? Even if we received and understood an alien message, its senders might be long gone by then. A study found that, if civilisations lasted fewer than 100,000 years, the odds of detecting a signal while the transmitting civilisation still exists are almost nil. So there's not much hope of sending (or receiving) a reply. [Ed, note. I don't understand this one. Presumably it assumes advanced civilisations are very far away, or not seeking communication???].


Cat

 

[xavier.hodge2024]

15 Theories on Why We Haven’t Met Any Aliens Yet

• Interstellar Distance: This suggests that even if intelligent life is common, interstellar distances are so vast that spacefaring civilizations are simply too far apart to have found each other yet. Our galaxy alone is 100,000 light-years across. >>>while interesting it also suggest that no civilization out there has, or could have, advanced beyond us.
• Lack of interest: Some propose that advanced civilizations may not view contact with us as worthwhile. They may be indifferent, focused inwardly, or consider us too primitive to interact with. From their view, we may not seem significant enough to initiate contact. >>>funny yes …insulting to be sure.
• The communications Gap Hypothesis: This theory suggests that we might be using the wrong methods or technologies to communicate with extraterrestrial civilizations. They might be using a form of communication that we haven’t discovered or understood yet. If this is true, we might be missing signals or messages from them because we don’t know what to look for. >>>also, interesting but in its own way still in line with a conclusion that can be drawn from #1.
• Rare Earth Hypothesis: This hypothesis suggests that the conditions necessary for life—especially intelligent life—are incredibly rare in the universe. It’s not just about having a planet in the habitable zone, but also about many other factors, such as having a stable star, a planet with a magnetic field to protect from harmful solar radiation, and the right mix of elements. This would mean that life, particularly intelligent life, is exceptionally rare, making our existence quite extraordinary. >>>well let’s face it this is self-sustaining and, in a sense, expands on the long-held idea that earth is the center of the universe type belief.
• The Great Filter: The Great Filter hypothesis proposes that there’s a barrier or filter that prevents civilizations from progressing to the point of widespread space colonization. This could be anything from a natural disaster, like an asteroid impact or gamma-ray burst, to self-inflicted destruction through nuclear war or ecological disaster. If this is true, it could mean that humanity has a significant hurdle in our future that we’ll need to overcome to avoid extinction. >>>wow a self-fulling prophecy …unless and until it is actually proven wrong it is always right.
• Zoo Hypothesis: The Zoo Hypothesis suggests that there are advanced civilizations out there, but they’re avoiding contact with us. Like zookeepers observing animals, these civilizations might be watching us from a distance, allowing us to live and evolve without interference. If this is true, it could explain why we haven’t had contact with extraterrestrial life despite the vastness of the universe. >>>let’s face it this one while more than just a little bit insulting may actually have a little basis in truth.
• Transcension Hypothesis: The Transcension Hypothesis proposes that advanced civilizations invariably leave our universe. They might create and move to a simulated universe, ascend to a higher plane of existence, or something similar. This would mean that these civilizations are not extinct or avoiding us, but simply exist in a realm that we’re currently unable to perceive or interact with. >>> Oh, wow talk about delusions of grandeur …humans will one day attain the status of gods??
• The Simulation Hypothesis: This hypothesis suggests that we’re living in a simulation, and the aliens are the ones running the simulation. In this scenario, we haven’t met them because they’re outside the simulation and choose not to enter it. This theory raises philosophical questions about reality and our perception of the universe. >>> if you can’t explain it all than it’s just because its not real?
• They’re Already Here: Some people believe that aliens have already visited or are living among us, and that this is being covered up by governments around the world. Evidence for this theory is largely anecdotal and not widely accepted by the scientific community. However, if true, it would mean that we’re not alone in the universe and that our first contact with extraterrestrial life has already occurred. >>>personally, I like this one.
• Self-Destruction: This is a darker hypothesis suggesting that once civilizations reach a certain level of technological advancement, they inevitably destroy themselves. This could occur through means such as nuclear war, ecological disaster, or a poorly controlled artificial intelligence. If this is true, it serves as a warning for humanity to be cautious as we continue to advance technologically. >>> umm a narrowing of # 5?
• The Planetarium: This theory suggests that we live in a simulation, or an artificial environment created by a higher intelligence. They control what we observe and can manipulate our understanding of the universe, making it seem as though we are alone. If this is true, our understanding of the universe and our place in it could be fundamentally flawed. >>> again, a narrowing of a hypothesis # 8?
• The Berserker: This theory suggests that an advanced alien civilization has created self-replicating probes (berserkers) that destroy other life-forming civilizations to prevent potential competition. If this is true, it could mean that we’re in a universe filled with predatory civilizations, and we might need to be cautious about attracting attention to ourselves. >>> I like this one too …we haven’t become quite as bad as we will eventually become …at which point we might have achieved gladiator status for the entertainment of our creator(s)?
• The Gaian Bottleneck: This hypothesis suggests that it’s difficult for life to evolve past the single-cell stage due to harsh conditions on young planets, making complex life rare. If this is true, it would mean that while simple life might be common in the universe, complex life like plants and animals (and intelligent life) is exceptionally rare. >>>A slightly different but also in line with a different Hypothesis # 5.
• The Resource Exhaustion: This theory proposes that civilizations might wipe themselves out through over-consumption of their planet’s resources before they get a chance to become space-faring civilizations. If this is true, it serves as a warning for humanity to manage our resources carefully to avoid a similar fate. >>>what can I say I like this one which although it is in its own sense a re-aiming of # 5 …because it does emphasize my point as to why we should move beyond our home planet.
• The Panspermia: This theory suggests that life is spread throughout the universe by asteroids, comets, and other celestial bodies. It implies that life on Earth could have originated elsewhere in the universe. If this is true, it would mean that life is not unique to Earth and could exist wherever the conditions are right. >>>not sure why this one would be a part of an explanation as to Why We Haven’t Met Any Aliens Yet.

So, if you may allow me to replace # 15 with my own.

The Alien, Human vs Hunam, Alien Paradox Hypothesis _ I humbly suggest that the biggest and only reason we have yet to have found proof and or met aliens whether human in appearance or not. Is because we are just not ready, or rather they know we are just not ready. If a civilization were in fact capable of traversing (i.e. traveling between and throughout the universe) galaxies; I would have to conclude that they have advanced enough to see and recognize where any civilization they happen to encounter is in the rational ability to accept, let alone live with, that kind of reality. In essence where, making contact, before that concept of rationality is present might lead to unwanted outcomes.

do they even exist

 

[arturo.v.dominguez@gmail.]

do they even exist

That could be the operative question. Which then begs the question do we want to know? If the answer is yes ...then how do, we go about finding out? If the answer to that question is no ...then does it matter?

 

[arturo.v.dominguez@gmail.]

Further to my post #93, I have come across some further points to augment the above.
These are from Science Focus, Vol 16, 2019, page 31. My notes. Not my points.

1. Could we decode (alien signals)? We have only been sending relevant signals for around 80 years, mostly relatively powered - and all analogue. We are now switching to digital signals, which are much easier to detect, but only if the encoding system is known - otherwise they could easily be mistaken for background static.

2. Could we understand it? Although the Arecibo message contains very relevant information (counting structure, DNA info, etc., it is cryptic and maybe difficult for other humans to understand. A corresponding alien message might be very difficult for us to understand.

3. Are they still there? Even if we received and understood an alien message, its senders might be long gone by then. A study found that, if civilisations lasted fewer than 100,000 years, the odds of detecting a signal while the transmitting civilisation still exists are almost nil. So there's not much hope of sending (or receiving) a reply. [Ed, note. I don't understand this one. Presumably it assumes advanced civilisations are very far away, or not seeking communication???].


Cat

The only true (intelligent/civilized) life forms we can attest to, in as far as their existence's longevity, are those we have found here on earth.