The Fermi Paradox

[QED]

In this debate I would like to see some resolutions offered to The Fermi Paradox:

[T]he apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.

The extreme age of the universe and its vast number of stars suggest that if the Earth is typical, extraterrestrial life should be common. Discussing this proposition with colleagues over lunch in 1950, the physicist Enrico Fermi asked: "Where are they?"

Note that when it comes to the colonization of our galaxy it would take only one ETC (extraterrestrial civilization) to pull it off. So offering an explanation such as "they blow themselves up before they embark on a program of colonization" wouldn't be particularly convincing as it would have to be something that got in the way of all ETC's ambitions.

Colonization seems to be a reasonable expectation as life appears to spread wherever resources permit. Various estimates range from around one to ten million years for a wave of colonization to sweep throughout the galaxy -- based on propulsion systems consistent with known physics. Although long in terms of a civilization, this kind of time-scale is nothing in terms of the age of the universe and is within the span of many of our own terrestrial species.

So, given the conservative estimate that conditions in the universe were amenable to life some 3 billion years before us (Livio 1999) we might expect ETC's to have expanded into every conceivable niche, or at least have left evidence of such an expansion behind by now.

Question for debate: Where are they?

[QED]

Hello Yarn -- and welcome to the DC&R forums

Note that when it comes to the colonization of our galaxy it would take only one ETC (extraterrestrial civilization) to pull it off. So offering an explanation such as "they blow themselves up before they embark on a program of colonization" wouldn't be particularly convincing as it would have to be something that got in the way of all ETC's ambitions.

Why couldn't it be something which got in the way of all ETC's amibitons?

Do you not think it unlikely that all civilizations self-destruct before they send self-replicating engineering out into interstellar space? Once an ETC gets past the "all eggs in one basket (planet)" stage then there would seem to be a kind of guarantee that they would continue to persist from there onwards.

I would agree that evolutionary origins for all ETC's would be likely to make the innate kind of aggression that frequently sets man against man a common factor among all intelligent species, but I am not so pessimistic as to imagine that nobody can dispense with that heritage in favour of a more peaceable strategy before it's too late. A synthesis of understanding between evolutionists, neuroscientists and game theorists could be the turning point towards a non-aggressive paradigm.

Furthermore interstellar travel is barely possible, the Earth is 2-6 billion years younger than the milky way, and it took life over 4.5 billion years to get to where it is. The probability of intelligent life in the milky way has perhaps been increasing since the galaxy formed, and the renaissance may be (in stellar time period terms) only now getting underway.

Now there's some info I'm short on: a quick google for "the age of our galaxy" came up surprisingly empty. 2 to 6 billion years is quite a big difference! Our Solar system must be at least 2nd gen. to have such a wide array of heavy elements therefore we know we it all to some supernova that exploded more than 4.5 Billion years ago but...

The mass of a star that goes supernova is a minimum of 8 times greater than that of our own star, but could be hundred times greater. The life of some "supersize" stars is measured in thousands not billions of years -- so it seems difficult to pin down a starting point for the evolution of life in our 6.5 to 10.5 billion year old galaxy (if your 2-6 figures are correct). Do you or anyone else have any useful references for this information?

[Yarn]

I would agree that evolutionary origins for all ETC's would be likely to make the innate kind of aggression that frequently sets man against man a common factor among all intelligent species, but I am not so pessimistic as to imagine that nobody can dispense with that heritage in favour of a more peaceable strategy before it's too late. A synthesis of understanding between evolutionists, neuroscientists and game theorists could be the turning point towards a non-aggressive paradigm.

What is needed for interstellar travel is technology, will, resources, and prospects.

The time it takes to have the first three all together at once, minus the time it takes gain the power to destroy civilization on the homeworld, may be such that the Fermi paradox is explained therein alone. If the human race were not diminished by global warming, nuclear holocaust, or some sort of resource (oil, iron, etc) crisis, it would probably be at the point where it would be ready and willing to do what it takes to colonize a foreign world in a few centuries from now. It is not very likely this era of progress will last a few more centuries.

I mentioned prospects. Even if everything else is in order, in many cases there won't be a colonizable world within detectable and/or travelable range.

Do you or anyone else have any useful references for this information?

An expert on the age of cosmic objects could probably be more specific here, but I do know that life takes a really long time to evolve to this stage (over 3 billion years on Earth, the Earth itself is 4.6 billion years) and hospitable solar systems haven't always been around. Furthermore, the Sun is gradually heating up and will make the Earth too hot for life within 1 billion years. Bad Astronomy says 200 million years, Astronomy Cast says 500 million, and wikipedia says 900 million.

[alexiarose]

In this debate I would like to see some resolutions offered to The Fermi Paradox:

[T]he apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.

The extreme age of the universe and its vast number of stars suggest that if the Earth is typical, extraterrestrial life should be common. Discussing this proposition with colleagues over lunch in 1950, the physicist Enrico Fermi asked: "Where are they?"

Note that when it comes to the colonization of our galaxy it would take only one ETC (extraterrestrial civilization) to pull it off. So offering an explanation such as "they blow themselves up before they embark on a program of colonization" wouldn't be particularly convincing as it would have to be something that got in the way of all ETC's ambitions.

Colonization seems to be a reasonable expectation as life appears to spread wherever resources permit. Various estimates range from around one to ten million years for a wave of colonization to sweep throughout the galaxy -- based on propulsion systems consistent with known physics. Although long in terms of a civilization, this kind of time-scale is nothing in terms of the age of the universe and is within the span of many of our own terrestrial species.

So, given the conservative estimate that conditions in the universe were amenable to life some 3 billion years before us (Livio 1999) we might expect ETC's to have expanded into every conceivable niche, or at least have left evidence of such an expansion behind by now.

Question for debate: Where are they?

I am going to throw something out here. Suppose we are indeed a branch of alien civilizations. Because of our violent natures, perhaps we were dumped here to prevent us from contaminating or corrupting the original civilization. Just as if we isolate the dangerous criminals in prisons, perhaps we are isolated here the same. Of course, I couldn't prove any of this, but if we were the only self-destructive species, then isolating us here seems to be the best alternative and why would anyone bother checking up on us? It isn't like our violent natures have evolved that much over time is it?

[Perdition]

As explained to me clearly by my old astronomy professor at Tulane, Dr. Frank Tipler, if advanced civilizations were out there, we would have already found clear evidence of their presence right here on earth.

Consider that exploring the Milky Way Galaxy requires no more propulsion technology than already exists within mankind's capabilities. We need only add computers with the ability to self-replicate. (Another century, tops.) Then launch these self-replicating probes toward the nearest star systems and just sit back and wait a few hundred thousand years while they land on every habitable planet in the Milky Way. Within an eye-blink in cosmic terms, mankind will have visited by surrogate every corner of the galaxy and left a broadcasting calling card on each one announcing our presence. If we can do this after only 4 million years of evolution, then the question remains, given the universe has been here at least a thousand times that long, where are they indeed?

Answer: they just don't exist.

[HughDP]

As explained to me clearly by my old astronomy professor at Tulane, Dr. Frank Tipler, if advanced civilizations were out there, we would have already found clear evidence of their presence right here on earth.

Consider that exploring the Milky Way Galaxy requires no more propulsion technology than already exists within mankind's capabilities. We need only add computers with the ability to self-replicate. (Another century, tops.) Then launch these self-replicating probes toward the nearest star systems and just sit back and wait a few hundred thousand years while they land on every habitable planet in the Milky Way. Within an eye-blink in cosmic terms, mankind will have visited by surrogate every corner of the galaxy and left a broadcasting calling card on each one announcing our presence. If we can do this after only 4 million years of evolution, then the question remains, given the universe has been here at least a thousand times that long, where are they indeed?

Answer: they just don't exist.

That sounds a bit simplified to me.

Let's assume we're an average race of beings on an average planet around an average star.

It's taken us 4 billion years to evolve this far, which is nearly a 3rd of the universe's lifetime.

So we'd be looking at races that have either evolved faster or live in older solar systems. They'd have to have evolved enough to build the self-replicating probes you propose and develop propulsion systems at least as good as ours (if we go with your assumption that current Earth propulsion systems are good enough).

If they can create self-replicating probes it would take about 190,000 years to generate one for each star in the galaxy even if they were advanced enough to replicate one a minute.

Let's assume the average star is 23,000 light years away, which is the distance to the centre of our galaxy.

Let's be generous assume our aliens can travel at 500,000 MPH - that means it would take about 30 million years to get to the average distanced star.

Furthermore, alien civilisations would actually have to want to undertake such a project. We tend to assume that technically advanced civilisations would (a fair assumption I suppose), but it's not certain.

Then we'd have to consider how life may be spread out amongst the 100 billion galaxies in the universe. Intergalactic distances are just too forbidding, even at a decent fraction of light speed.

There could be millions of planets with life on them in the universe, yet we could still have virtually no chance of contacting them.

[Smorb]

As explained to me clearly by my old astronomy professor at Tulane, Dr. Frank Tipler, if advanced civilizations were out there, we would have already found clear evidence of their presence right here on earth.

Consider that exploring the Milky Way Galaxy requires no more propulsion technology than already exists within mankind's capabilities. We need only add computers with the ability to self-replicate. (Another century, tops.) Then launch these self-replicating probes toward the nearest star systems and just sit back and wait a few hundred thousand years while they land on every habitable planet in the Milky Way. Within an eye-blink in cosmic terms, mankind will have visited by surrogate every corner of the galaxy and left a broadcasting calling card on each one announcing our presence. If we can do this after only 4 million years of evolution, then the question remains, given the universe has been here at least a thousand times that long, where are they indeed?

Answer: they just don't exist.

We have the current technology today to map the bottom of the ocean and catalog every living species on the planet. This could prove one of the most enlightening and important scientific endeavors. Finding new species and learning about the last part of the world thats extremely difficult to explore. how many species are down there right now that we dont know about? a very large chunk of the species that inhabit the earth live where we have never been. Think of what we have learned from our exploration of the surface of the earth, imagine what we could learn from the other 70%. We aren't doing this. It is within our reach, and we are giving it about as much attention as we are giving to finding Elvis. Assuming that an advanced civilization exists we have no way to determine their goals.

We are a very rare species, so rare, we are one in a very very large billion of numbers. The earth has seen many many catastrophes that have wiped the planet of certain species forever, leaving behind only the bare minimum of evidence. We are lucky, we have a giant red planet around us to suck up a lot of interstellar asteroids and debris that might otherwise hit us. There are so many factors in the Drake equation that have to be met, including a civilization who can function without conflict (which seems extremely rare) that the number of surviving species who have access to space travel like us, it does not seem unlikely that we have never, nor will ever meet them.

It would be the most momentous occasion in recorded history to meet another civilization and would turn the course of Man forever, but our current course does not leave a lot of time left on our expiry date. Unfortunately, this may not be terribly uncommon.

[QED]

As explained to me clearly by my old astronomy professor at Tulane, Dr. Frank Tipler,

How very lucky you were to have Tipler as your mentor I'm green with envy!

if advanced civilizations were out there, we would have already found clear evidence of their presence right here on earth.

Maybe we're it? I really can't agree with this statement yet. There are many reasons why we shouldn't expect to have observed them in the EM spectrum and I doubt that we have put sufficient effort into exploring our own back yard (solar system) to see if there's any direct evidence of past encounters. In one of Stephen Baxter's SF novels some significant features of the solar system turn out to have been the result of past alien engineering projects -- a fanciful idea maybe but we still don't know all there is to know about the past history of our own star system -- let alone others (I've long thought that it would make a good story to explain the tilt of the planet Uranus, which is almost parallel to the ecliptic, as the consequence of some great battle!).

Tales of Science Fiction aside, I would like to know where Frank Tipler's confidence that any alien presence would be clear to us comes from.

Consider that exploring the Milky Way Galaxy requires no more propulsion technology than already exists within mankind's capabilities. We need only add computers with the ability to self-replicate. (Another century, tops.) Then launch these self-replicating probes toward the nearest star systems and just sit back and wait a few hundred thousand years while they land on every habitable planet in the Milky Way. Within an eye-blink in cosmic terms, mankind will have visited by surrogate every corner of the galaxy and left a broadcasting calling card on each one announcing our presence. If we can do this after only 4 million years of evolution, then the question remains, given the universe has been here at least a thousand times that long, where are they indeed?

Answer: they just don't exist.

Why would such probes necessarily leave behind such unmistakable calling cards? Maybe the Asteroid Belt has already been mined to depletion of materials needed for further propagation waves -- would we know it? I suspect we could but I doubt if any serious attempt has been made to do the necessary auditing!

[Cathar1950]

QED, did you read about the star exploding about 7.5 billion years ago?
It was first seen just a bit ago and they were talking about Gamma rays that travel near the speed of light and I was wondering how long it might take for them to reach us given the light took 7.5 billions years to get here.
Maybe I can find the piece. I know it is off topic but I was thinking about mass extinctions and other planets.

[earl]

QED asks ,"Where are they?"
Has all avenues of search been exhausted?If so ,
Have you researched things spiritual to discover, "where are they?"or,is this route not your cup of tea?

[HughDP]

QED asks ,"Where are they?"
Has all avenues of search been exhausted?If so ,
Have you researched things spiritual to discover, "where are they?"or,is this route not your cup of tea?

I think you'll have to expand on that a bit. How will spiritual exploration determine the existence of extraterrestrials?