Expanding Advanced Civilizations

[antoniseb]

Here's a paper about expanding civilizations, by a German Scientist named Claudius Gros:
Expanding Advanced Civilizations in the Universe

He does some calculations, but I didn't see anything especially innovative in the paper.

[Bobunf]

I think speculations about extra-terrestrials contacting us must be seriously impacted by the probability that advanced civilizations will detect the existence of life in other star systems.

Before the end of the next decade NASA’s Terrestrial Planet Finder and the European Space Agency’s Darwin missions are designed, to quote NASA’s website, to “measure the size, temperature, and placement of planets as small as the Earth in the habitable zones of distant solar systems…will allow atmospheric chemists and biologists to use the relative amounts of gases like carbon dioxide, water vapor, ozone and methane to find whether a planet someday could or even now does support life.”

It seems reasonably probable that by 2100 we should be able to detect life bearing planets across most of our galaxy. The Earth has been giving off these signals for at least hundreds of millions of years—about a thousand times longer than is needed to cover our whole galaxy.

How would we feel about a planet just about Earth size and gravity, with the right temperature, water, a 20% oxygen atmosphere, no poisonous gases and a nice ozone layer 50 light years away? In 2005 we’ll only dream, but by 2105 I would like to think we’ll be able to do a lot more than just dream.

A species a thousand years more technologically advanced than us would, I think, not find too great a challenge venturing on a 50 light year journey with a colony planting spacecraft. We might not find it too great a challenge in the 22nd century, let alone the 30th.

A species with colonies with a net reproduction rate of once every thousand years would have a thousand off-spring in less than ten thousand years. One would think that the number of star systems they would have explored would be much higher.

I think any advanced civilization will know there is life here on Earth, and that it’s been here a very long time. The number of star systems that harbor old life giving off robust signals must be fairly limited, which, I think, makes Earth a prime target for further study.

Besides which Earth has been giving signals of intelligent, technological life for thousands of years—getting gradually easier to detect right up to radio waves starting in the 20th century. But long before then, probably easily detectable by 30th century science, we’ve given signals:

Lead in the atmosphere used in metal working for more than 8500 years. 2500 years ago lead increased hundreds of times above normal levels transported to Greenland through the atmosphere from Carthaginian and Roman Spanish Mines. It should be quite possible to differentiate on-going metal working by-products from sporadic natural events, such as lead emissions from volcanic eruptions.

Coal has been widely used for more than a thousand years; releasing radioactive uranium and tho-rium into the atmosphere, as well as a host of other pollutants.

DDT, kerosene, naphthalene, gasoline, benzene, chloroform and many other volatile chemicals have been used for over 150 years.

Detecting freon in the atmosphere, and observing its distribution over time, would not only show we are here, but would pinpoint the state of our technology within a few decades. Wide-spread use of freon goes back to about 1929.

All of this must make Earth a very interesting object for study. In which case, as Fermi said, “Where are they?”

Bob

[eburacum45]

It seems reasonably probable that by 2100 we should be able to detect life bearing planets across most of our galaxy

I think that is somewhat overoptimistic, and does not take into account how big the galaxy is, and how small earth-type planets are. Even given optical interferometry with a baseline the size of Jupiter's orbit we are unlikely to be able to detect earth type planets more than ten thousand light years away; I think we would be lucky to be able to detect them at that distance. So the vast majority of the stars of our galaxy will be beyond the reach of our instruments for many hundreds of years.
What we may be able to detect at great distances is the apparent signature of life; such things as free oxygen, ozone, water vapour; yet without a closer look we could be mistaken, led astray by non-biological processes which reproduce the apparent signs of life.

[folkhemmet]

The paper on Expanding Advanced Civilizations' most important point is that once a civilization starts expanding into the universe this expansion is not necessarily open-ended. We are at a strange time in our quest for discovering life in the universe-- that is, we have good reason to believe that the universe is awash in planets and that life is resilient, but we still don't have enough data to narrow down the number of the competing hypotheses about the abundance of complex life.

As for the prospects of detecting life bearing planets throughout most of the galaxy, I think they are pretty dim. The only technique for finding planets that are across the galaxy is called microlensing. I think one Jupiter-sized planet was already detected using this technique. Earth-sized planets may be detected via microlensing in the relatively near future; however, the observation is not repeatable and there is no way to get information about the planet's atmosphere even when the observation is made, as far as I know. TPF and Darwin would only be capable of finding life-bearing planets out to about 40-50 light years. If a "blue-marble" (Carl Sagan's term for a habitable earth-like planet) is found I wonder what kind of effect this would have on increasing the chances of our civilization becoming an expanding one. I would hate to think that humanity will never enter into what would be the grandest age of exploration conceivable.

[JimAA2QA]

Considering the problems in the Middle East, in Africa, and other places around the world, the question is *if* an advancing civilization doesn't destroy itself with advancing technology with which it is unfit to possess ...

Best regards from Rochester, NY
Jim

[Bobunf]

I developed a rough chart about our changing ability to detect planets bearing the kind of life that exists on Earth:

Year Distance
1600 10^5 kilometers. Using the naked eye
1700 5x10^5 kilometers. After the invention of the telescope
1800 5x10^6 kilometers. Better telescopes.
1900 10^8 kilometers. Even better.
2000 10^12 kilometers. Adaptive optics, space based instruments, etc.
2025 5x10^14 kilometers—about 50 light years. TPF, Darwin and others.

It doesn’t seem much of a leap to extrapolate that in 2100 the distance will be 10^18 kilometers—about 100,000 light years. If not by 2100, certainly by 2200, or 2300.

Maybe some difficulty will develop. No new approaches to this problem will come to be understood and developed. Maybe, for some reason, it will be impractical to expand on the approaches of the Terrestrial Planet Finder and Darwin to extend our reach a few orders of magnitude.

But to me the most probable scenario is that advances in astronomy and all the associated fields will continue at an increasing rate, as has been the case for at least five centuries.

So, I think any ET, even a few centuries more advanced than us, will be perfectly aware of life bearing planets to a very considerable distance from its home--probably covering most of the galaxy.

Bob

[astromark]

A thought I would like to share....
If there had not been life extiction advents on this planet would we have advanced to a greater extent or not. Could it be possible for other systems to have evolved for much greater periods of time without interuption. could we be late on the scene becouse of this? Would humanity have risen at all if the gerasic period had endured.
My point is this, that even if we find a blue dot. It might not be what we are looking for. Our history is short. we are only at the beginning of this encredable age. If we can educate the global comunity into a state of informed well adjusted people we might servive long enough to take the bait and launch our selves into the cosmos. The following idea is not mine, as you will see its been around for decades and issent based on good scientific evadance. Is it possible that life forms have allready found us? and they left us some rules to help us servive our own stupidity. Or did they stay and breed with us. Are we the descendance. No probebly not. but its gaining momentum as a viable explanation of our sudden evolution... What better way to explain your visate than to become gods. All a bit childish I think but I cant competly reject the idea as rubish. I should try harder.

[GOURDHEAD]

we have good reason to believe that the universe is awash in planets and that life is resilient, but we still don't have enough data to narrow down the number of the competing hypotheses about the abundance of complex life.

True, however once a civilization achieves interstellar transportation competence and the advantages bestowed on any such civiliztion driven to technological competence through competition with sibling species at its origin; it will densely populate the region of the MW from which it emanates thus enhancing its detectability. The absence of detection of such critters is good news for our ultimate survival, although no guarantee.

[Bobunf]

"The absence of detection of such critters is good news for our ultimate survival, although no guarantee."

Why do you think this is good news? I can think of multiple reasons why it's bad news:

1. The absence enhances the possibility that one of the reasons for no detection is that techno-logical civilizations don't last very long. Not good for us at all, I think.

2. The reason for the absence is that intelligent life is extremely rare with a probability of less than one per galaxy. We'll miss out on all the huge advantages of sharing with a whole different evolutionary track.

3. They’re keeping themselves hidden in preparation for the invasion. (Just kidding)

So, why do you think it’s good news.

Bob

[GOURDHEAD]

So, why do you think it’s good news.

Extrapolations from the results of contacts between the more technically advanced Europeans and indigenous populations elsewhere. My fantasy is that things would have gone better for the indigenous ones had the technological playing field been more equal. I hope our stellar and galactic neighbors will be benevolent, but there's no guarantee they won't be malevolent. Pragmatism enhances non-malevolence when competences are equivalent.

In other threads I have questioned whether the time required for sufficient stellar cycling to produce sufficient life (as we know it) supporting elements is significantly larger than that at which the solar system (and us) formed and have posited that we may be among the first with technological competence to emerge. Hence others will have constrained headstarts; although they could still be millions of years ahead of us. If they were millions of years ahead of us, we could not avoid detecting them because of the effect they would have had on the MW (maybe even on M31). Hence we aren't too far behind the leaders...that's fortunate.

Considering the durability of technological civilizations, some probably don't survive into their space age; others do and after sufficient competence levels are reached, the probability of their demise rapidly approaches zero and the ranges of their habitats are greatly enlarged. If we can make it another 500 years free of major setbacks, the universe will be putty in our hands so to speak.

[eburacum45]

This paper by Milan Circovic suggests that an advanced civilisation may regress into a less complex but more stable state over time;
http://arxiv.org/ftp/astro-ph/papers/0408/0408521.pdf

this is possible in some cases of the development of advanced civilisations; maybe in many cases, but I do not expect that it will necessarily happen to all expanding civilisations; therefore it does not seem to be a complete answer.

[Bobunf]

“Extrapolations from the results of contacts between the more technically advanced Europeans and indige-nous populations elsewhere.”

What is your understanding of the results of these contacts? To put it another way, what percentage of Mexicans today would wish that the Spaniards had never come?

Determining actual impacts is difficult because of the issues of nationalistic and racial pride and dignity, individual atrocities remembered disproportionately, lack of comprehensive knowledge and misperceptions about the past, and other issues. But to try to apply objective measures, overall native Americans in the United States and Canada today have larger numbers than in pre-Columbian days. On average life expec-tancy is significantly higher, and incomes per capita are much higher.

Overall the results have not been entirely negative, and, one could argue, have been beneficial on balance.

Also, is the modern European experience typical of contacts between asymmetric cultures? I think, on balance, many other such contacts have generally been more beneficial.

Bob

[GOURDHEAD]

What is your understanding of the results of these contacts?

Domination of the European culture at the expense of the comfort and many lives of the less technologically competent. Somehow we managed to avert total disaster for those more primitive cultures. The more control we can have over our comfortable survival, the better off we will be.

[astromark]

This is getting interesting. We talk about this as if we are in control. I do want to know, but am concerned. Making contact with an ET could be the end of us. If they behave as we have we are history. Our track record is dredfull. With few exeptions. I admit most cultures have servived and prospered from the invasion of the westerners, and would not want to go back. They could not or would not be allowed to anyway. Once the damage is done... I have this nagging feeling that this could be our undoing. We might be there next meal. Maybe the time and distance is what has protected us thus far.
I would like to add, We have two eyes ( good for colecting visable data )
We have two ears ( far the colation of audio signals )
We have one mouth. Lets use it for eating untill we know we are not going to be chicken feed for some other life form.
For our own safty we should be quiet. Look and listen more than scream our existance. I am not sagesting we should not be exploring our local group of stars, just sounding a note of coution. We may not like what we find,and are allmost powerless to defend ourselvs...

[filrabat]

We have already advertized our presence - especially for the past 60 or so years (radio and TV you know - those EM waves go on essentially forever).

As for such "evil aliens" coming to Earth for nefarious reasons - it's not like we could do anything about preventing the journey - not any more than the Aztecs could prevent Hernando Cortez's journey to Mexico in 1519. If they have the desire and ability to come here, they are going to do so, like it or not. Unless we are willing to turn our Earth into a radioactive desert, we won't be able to stop it (which we might very well be willing to do if aliens did come to conquer us for our resources).

At any rate, if such a nefarious alien civilization did want our planet, I seriously doubt they would actually land an invasion force a la War of the Worlds or Independence Day. I find it FAR more likely they would manufacture some latent deadly microbe, build a fleet of mini-probes to be launched from space craft journeying to just outside our detection range (say at 4 or 5 times the sun-to-pluto distance), and fire the mini-probes from there. All they'd have to do is wait for the microbes to do their work. It'd be a whole lot cheaper than landing an invasion force, or even sending a single warcraft into orbit around the earth and zapping all our cities at once.

[GOURDHEAD]

Some 10 to 20 thousand years ago (?) a primate species enslaved the equine, bovine, canine, etc., species with a mix of benevolent and malevolent motivations. This is the sort of interaction I would expect from advanced extraterrestrials as opposed to an all out attack; also, the benevolence/malevolence ratio would be much higher than that practiced by us and our forebears. But we would be less free and freedom is a highly prized condition with us. Such critters would most likely have passed through the "rule of tooth and claw" equivalent phase their own evolution and have evolved a "rule of law" phase richly endowed with attributes similar to the ones we consider to be virtuous. Consequently, if they chose to rule over us, we could expect a high level of fairness; the danger is that they, free of intentional malevolence, will love us to death, or at least into insignificance.

At a minimum we would be constrained to using the part of the universe they choose to leave for us. So, again I say, we are lucky that there is no evidence of any critters very advanced beyond us. This is not the time to rest on our laurels.

We have already advertized our presence - especially for the past 60 or so years (radio and TV you know - those EM waves go on essentially forever).

They do indeed but I doubt the omnidirectional ones can be separated from noise at the distance of Alpha Centauri.

[Bobunf]

I don’t think there could be a rational reason for an advanced extra-terrestrial civilization to invade Earth for resources. Any resources we have could be more easily, cheaply and quickly procured from comets, asteroids, Kuiper belt objects, uninhabited moons and planets in our solar system; let alone the possibilities they would have in other star systems.

Invasion for purposes of population movement wouldn’t make any sense either. It would be far easier, cheaper and quicker to construct habitats on other objects in their solar system like Kuiper belt or Ort cloud analogues (trillions of objects), the most luxurious O’Neil type colonies, or to move inward through their planets crust and mantle.

There’s millions of times as much surface area on Kuiper belt and Ort cloud objects as on Earth. Colonies in space could multiply that surface area even more. If one regards humans as occupying a ten kilometer wide zone on, above and under the Earth’s surface (a very generous regard), there’s nearly a hundred times as much space, and resources, within the first 1000 kilometers of the mantle, not to mention the interior of other objects in the solar system. And there are undoubtedly many other possibilities I haven’t thought of.

It seems to me the only rational reason to invade Earth would be for colonization. They intend to come and live here, occupying the space we currently live in.

Of course, there are also irrational reasons. There’s no guarantee that ET will be immune to madness.

Bob

[Bobunf]

It amazes me that some people feel the only way for ET to know we are here is if we send him a radio signal—intentionally or not. Ignored are the huge changes that life has produced on our planet, and that we will be able to detect within a few years up to about 50 light years distance.

So if advanced ET employs the equivalent of 2020 AD technology (that’s 15 years more advanced than us, not 15 hundred, or 15 thousand), he will know that the Earth has the right orbit and size for life; that Earth has water, 20 times as much oxygen as is conceivable from non-biological processes, and an on-going excess of methane. And he could have noticed these phenomena anytime for at least the last 500 million years.

If advanced ET should employ the equivalent of 2100 AD technology (that’s 95 years more advanced than us, not 95 hundred, or 95 thousand) he will probably know from thousands of light years away that Earth also has lots of chlorophyll exposed to the sky.

And if ET is close enough, he might be able to detect lead in the atmosphere from metal working as much as 8500 light years away. From twenty-five hundred years away ET might notice that the Romans increased the lead in the atmosphere, as identified in Greenland ice cores, hundreds of times above previously seen levels, an elevation that persisted for centuries.

Even closer ET might detect the pollutants from coal burning as much as a thousand light years away. In 1700 AD more than 5 million tons of coal were burned worldwide.

The atmospheric signals of more recent industrially produced gasses and pollutants are now reaching distant star system: chloroform 160 light years, kerosene, naphthalene and gasoline 150 light years, benzene 140 light years, DDT 130 light years; and the signal of atmospheric freon is now reaching star systems 76 light years away--involving nearly 10,000 star systems.

Besides all of that, ET might actually be more clever than us in at least some ways. He might think of other ways to figure out we’re here; maybe many other ways.

Radio, I think, is left far away, back in the dust.

Bob

[Relmuis]

Considering the possible adverse effects of contact with a more advanced civilization, I would like to make the following comments.

1. In human history these adverse effects have not just been a "Western" or "European" thing. For example, the Maori seem to have enslaved and eventually exterminated another Polynesian people living on a small island near New Zealand, the Bantu have marginalized both the Pygmies and the Bushmen, and China has its own history of atrocities and ethnic cleansing.

2. However, the conquerors were always humans. For all we know there may be something peculiar about human psychology which causes these unfortunate events, so we cannot know that something similar would happen if the more advanced of the two parties were non-human.

3. Moreover, the conquerors and the conquered belonged to the same species, which, in itself, may generate rivalry, conflicts of interest, and other forms of adversity, which might be absent in a meeting between radically different species. (We might not be able to use their tools, to eat their food or to catch their diseases; therefore our culture would not be compromised by our trying to imitate their lifestyle, to drink their liquor and/or to earn their money&#33

Caution would still advise not to initiate any contact if we can help it, however.

As regards the detection of alien civilizations, I have an idea which some of you may find peculiar.

Any alien civilization which has endured for, say, a million years, can be expected to put value on survival. (If they didn't care whether they survived, they wouldn't have lasted a million years. We are, as things are going at the moment, not likely to last another century.)

If they want to survive, they will have to prepare for some future state of the universe (Big Crunch, Big Rip, Funnelization, Heta Death, or whatever will prove to be the fate of the universe). Some of these preparations will probably entail huge engineering projects, such as moving worlds or entire solar systems, reorganizing galaxies, building black holes or Dyson spheres. The same kinds of threat will be perceived by any civilization anywhere in the universe, and these will engender the same kinds of solution, over and over again.

Therefore certain features which we think of as natural may in fact be artificial. For example; most galaxies seem to have a central black hole. Perhaps a natural process has created them, but perhaps they are the hallmark of galaxy-level civilization. Many stars seem to have a smaller companion. Some of these companions may be artificial as well; intended to outlive the original star and thereby provide light and warmth to its former planets. Or globular clusters might actually be created when inhabited solar systems decide to congregate outside the dangerous environment of the galactic plane. (The danger may be gamma-bursters, or something else which we are not yet aware of.)

So we might look for the signature of high-level civilization by looking at large-scale phenomena. We may be like ants who look for signs of another ant-hill, but fail to see the flyover between whose pilons they have always lived.

[Nyrath]

Originally posted by Bobunf@Jan 14 2005, 04:10 PM
I don’t think there could be a rational reason for an advanced extra-terrestrial civilization to invade Earth for resources. Any resources we have could be more easily, cheaply and quickly procured from comets, asteroids, Kuiper belt objects, uninhabited moons and planets in our solar system; let alone the possibilities they would have in other star systems.

Unless, of course we are the resources. Your argument holds true, unless (for instance) human brains are the missing ingredient for their immortality serum, or something like that.

There is also the chance that they want some resource that is worthless for our technology, but valuable for theirs.

As an analogy, there are a lot of tribal low-tech people in the Congo who have been killed as various non-tribal groups battle with high-tech weapons (i.e., guns, which look real high-tech compaired to a spear). The tribal people cannot seem to understand the reason that their villages have been destroyed and their people killed. The high-tech invaders are fighting over dirt. Dirt is worthless, why would anybody fight over dirt?

The tribal people just get more and more confused if you try to explain that this is a special dirt called colombo-tantalite or "Coltan". It contains something called an "element", an element named "tantalum". The tribal people get even more confused. And why is tantalum valuable? Well, it is required for tantalum capacitors, which are vital for cell phones. Somewhere between trying to explain what a telephone is, and how a cell phone is better, the tribal people become totally lost.

you can read more about this here:
http://www.seeingisbelieving.ca/cell/kinshasa/
http://www.globalissues.org/Geopolitics/Af...ndardColtan.asp

So, by analogy, aliens could show up some find day and start killing us and other aliens with high-tech weapons. We cannot seem to understand why the invaders want to strip mine entire continents for dirt. We will just get more confused if they try to explain that Earth just happens to have valuable deposits of pink polka-dotted quarks, which are vital for making crotted interositers.

[Bobunf]

Even though I think radio is the least likely way in which ET might find us, I don’t understand the 60 year number I see bandied about as the first possible time for detecting radio from Earth. Where does this 60 year number come from? And shouldn’t we take into account the idea that advanced ET will be more advanced than us? More capable of detecting things that we couldn’t? Maybe even capable of detecting things we don’t think could be detected?

I know there are all sorts of issues about power and how much energy will pass through the ionosphere, but I think a serious look at the volume of radio activity on Earth before 1945 should push the date for first delectability back several decades.

In 1898 Guglielmo Marconi installed the worlds first commercial radio service on Rathlin Island off the coast of Ireland; and in 1907 he established the world’s first trans-Atlantic commercial wireless service with stations at Clifden, Ireland and Glace Bay, Nova Scotia.

On April 14, 1912 the R.M.S. Titanic was busy most of the day and night receiving and transmitting radio traffic with Cape Race Wireless, in Newfoundland. The ship also received and acknowledged, by radio, warnings of ice from the Athina, Masaba, Californian, and several other ships. At 12:15 AM April 15, 1912, R.M.S. Titanic began sending distress signals which were picked up by the ship Carpathia 58 miles away. Carpathia rescued 705 of the 2228 passengers and crew of Titanic.

In September of 1922 there were 537 radio broadcasting stations in the United States and 100,000 radio sets were produced in the year. The rest of the world was using radio also, and it just kept getting bigger. With wavelengths shorter than 10 meters used for FM broadcasting begining in the middle 30’s.

Beginning in 1936 the British began construction of radar stations across much of the coast of England for detecting and following aircraft and ships using wavelengths of from ten to one and a half meters. Most of this radiation would have passed through the Earth’s atmosphere. British ships, aircraft, anti-aircraft artillery, even searchlights, were also equipped with radar. Planes and ships used radio IFF beacons and radio direction beams. As war approached and ensued the Germans, Italians, Russians, Americans, and Japanese used radio waves for communications, navigation, radar, IFF, and jamming throughout a good part of the world.

It seems to me that, with all this activity (and a whole lot more), dismissing everything that happened before 1945 isn’t giving ET much credit for detection ability. I don’t think anyone can say that it’s not possible.

Bob

[eburacum45]

"Crotted interoseters!"
LOL!

However Bobunf is mostly right;the Earth is unlikely to contain anything that can't be found on or inside Mercury, Venus and/or Titan.

Because of the Earth's geological history of volcanic mixing the crust of our planet is actually enriched with heavy metals and other elements that are probably going to be a little difficult to find elsewhere in the solar system; you might find uranium and gold rare except on Earth, although there may be some asteroids which are enriched in the heavier elements (Io has good volcanic activity, so may be enriched on the surface as well).
But in the solar system as a whole there should be no shortage of resources; there is no need to inavde Earth for material goods.

The Earth does have abundant life; it is unique in that respect, but aliens are likely to differ from Earth-life in their chemistry quite a lot, with different amino acids, proteins and other chemical differences which would almost cetrtainly make it impossible for them to eat us or our food and vice versa.
So no reason for them to farm us for lunch then.

The other thing Earth has is intelligent life and culture; they might want to study us as interesting psychological examples, and this examination could be excruciatingly thorough. Alternatively we could become a tourist attraction;
I don't believe in flying saucers and the ET hypothesis as such, but the bizarre behaviour of reported UFO's could be explained by a bunch of extraterrestrial psychologists experimenting on our monkey minds,
or by a series of guided tours by rubbernecking Alpha Centauris who are essentially insensitive to our culture.

[Bobunf]

Nyrath,

I think the political analysis contained in the article you referred to is inaccurate. Aside from that, it seems to me that for any physical resource, it would be an awfully long way, awfully expensive and time consuming for ET to travel to Earth from 100 or so light years away with all kinds of other opportunities in between or at least closer.

There’s also the idea of synthesis. ETs able to travel between the stars should be pretty good at chemical, biological and nuclear synthesis such that any need for a material could be satisfied by synthesis much more quickly and cheaply than by transporting anything a hundred light years.

So much for flawed tantalum analogues.

But I do think the resource would be us.

To try another analogy, I don’t think it’s appreciated how much the Old World has benefited, continues to benefit, and will benefit in the future from the technology and culture of the New World as it existed at the time of Columbus. Human culture had developed nearly completely independently for over 10,000 years in the New World, and the Native Americans had come up with some really important innovations.

Corn, tomato, squash, pumpkin, potato, tobacco, chocolate, and turkey were all domesticated and the technologies for producing and processing all of these crops were developed in the New World. Together these innovations constitute about a third of the world’s food production today. Europeans also received knowledge of different constellations, artistic traditions, creation stories, religions, a different way of understanding life, and much more.

The Americas were the last great human colonization event, and there are many things to learn about the process of this colonization that could be extremely useful if we come to colonize another new world, like Mars.

In addition to the direct benefits, there are also important things to learn about general principles of interactions between asymmetrically developed cultures. Our survival could depend on a sophisticated understanding of those interactions; if we encounter ETs more advanced than us, or beings intellectually superior to ourselves, such as computers ten generations from now.

ET will probably be as curious as us, and will probably understand the great benefit to accrue to ET from contact with life and a civilization that have evolved independently for an immense amount of time.

Bob

[albedo_1]

[COLOR=blue]Biological intelligent life forms do not survive the cataclysmic bombardments of space rocks.

In the last 25 years, since Dr. Alvarez postulated that the dinosaurs died out because of an extraterrestrial bombardment, we have found at least 150 other meteorite craters on earth. On every solid planet we find craters. Luna is largely a pockmarked testiment to what awaits the earth. Now, that we can decipher what they are telling us, we can understand that the law of astronomical entrophy is at work.

I am asking that the reader think "outside of the box". Perhaps, outside of the sphere, a device that has the most volume of any known container of similiar size, is more appropriate.

That it has taken 6 billion years for an intelligent life form to exist, is, in itself, very telling. Do we have the capability to comprehend what such a large time line is telling us? Is this akin to looking out at infinity and trying to define a metric to explain it?

It took that long to get where we are now, yet only one large space rock is necessary to reset the biological clock back to square one. It is estimated that such an occurence will happen every few 100 million years. Of course, Mathematician Poisson postulated that a random occurance can happen immediately after a previous occurence.
See:
http://tinyurl.com/4rwce

We could be guarding against our fate but how do we get those in power for a very limited time to fund a project that may not be necessary for 140,000+ generations but could be needed within the next 2 years? See Shoemaker-Levy-9, a long term comet, captured by Jupiter in 1993. It broke up and crashed into that gas planet within two years.

Australia could not convince their science director to fund a spacewatch program to the tune of 1 million $AU per year. Now, the US president refuses to fund the repair of the Hubble Telescope because it will cost 1 billion $US while we spend that everyday in Iraq.

How do we give our leaders the resolve to, at least, look for ECCs (Earth-orbit crossing comets)? BTW,a new class of ECC with an albedo of <1 is posit. We will need infared telescopes to see them.

It is estimated that the Oort belt has 10X10E11 comets, of which, 1% have the capacity to be an ECC.

With this new information we must conclude that Dr Drakes&#39;s formula is an unfortuneate example of GIGO. We just need to increase the timeline and add other variables to come to this conclusion.

Does this help explain Fermi&#39;s Parodox IE. if they(extraterrestials) exist, where are they?

If we wish to communicate with any other class 0 civilizations, should we ever find one, our message could be "Beware of space rocks".

If we continue our present course the legacy we leave behind will be the few small examples of our technology that we have deposited in space and on other bodies in our tiny solar system.

[Bobunf]

“Mathematician Posident [?} postulated that a random occurance (sic) can happen immediately after a previous occurance (sic)”

I don’t think “postulated” is the right word for this phenomenon, which one can easily observe. In five roles of a six-sided die, for instance, one will probably see the same side come up twice in a row at least once.

Of course it depends on the type of random occurrence. If one were randomly selecting balls numbered 1 to 100, and replacing the first ball only after it had been compared to the second ball, two numbers would never occur twice in a row.

Even though two 100 million year impact events could occur immediately following one another, by the same token an event with a 50% probability of occurring once every 100 million years will not occur for more than 500 million years about once every 32 times.

Nonetheless impacts certainly present a challenge to life.

As for our life, one gets “those in power for a very limited time to fund a project that may not be necessary for 700 generations” by dwelling on the two year possibility. People and governments spend lots of money all the time on things that may never be needed: fire alarms and smoke detectors, for instance.

And there is another way to look at these things in the light of limited resources and changing technology:

Alternative 1: Protect against 90% of the damage from impacts that might occur from 2010 to 2030 AD.
Cost: 10% of our resources.

OR

Alternative 2: Protect against 50% of the damage from impacts that might occur from 2010 to 2020 AD and 90% of the damage from 2020 to 2030 AD.
Cost:: 1% of our resources.

The probability that alternative 1 would prevent any damage not prevented by alternative 2 is one in twenty million.

It’s easy to see why many people would think alternative 2 was a better idea, especially since we have gobs of other things to worry about, and to use those resources for, like global warming, funding health care and arranging to educate the kids.

It seems to me that the danger of low albedo objects can be estimated from studying the energy distribution of objects burning up in the atmosphere and extrapolating from that data and other astronomical data. Fireball intensity is unaffected by albedo; althugh this approach wouldn&#39;t work if low albedo objects have a size distribution different from high albedo objects.

Bob

[folkhemmet]

Bobunf,

"Determining actual impacts is difficult because of the issues of nationalistic and racial pride and dignity, individual atrocities remembered disproportionately, lack of comprehensive knowledge and misperceptions about the past, and other issues. But to try to apply objective measures, overall native Americans in the United States and Canada today have larger numbers than in pre-Columbian days. On average life expec-tancy is significantly higher, and incomes per capita are much higher."

Actually, recent estimates suggest that the pre-Columbian Indian population of north and south America was much higher than the native population of today. Also, the degree of racial mixing has severely diluted the number of Native Americans. Here is one reference:

Pre-Columbian population estimates for the Americas vary widely.
-50 million to 100 million for the Americas
-15 million to 60 million for North America
-one million to 12 million for the area of North America that is
today the U.S. and Canada

http://www.clevelandstatecc.edu/Courses/ng...before_1492.htm

Also, studies have shown that after movies like &#39;Dances With Wolves&#39; came out in the early 1990s the number of people considering themselves Native Americans shot up. This leads to an inflated estimate of today&#39;s native population. My source:

American Indians in the 1990s, Dan Fost, American Demographics, December 1991

Even data on life expectancy suggests that the life expectancy of many native north and south Americans was as high as those of modern Europeans. The degree of environmental pollution was also orders of magnitude less. Moreover, the whole of idea of per capita income is rediculous when you consider the fact that there was, in most instances, a completely different culture and economic system in most pre-Columbian societies. Also, today poor health care, lack of education, and extremely high rates of substance abuse are clearly evident among huge numbers of American Indians today. Perhaps most important, you are conveniently forgetting the mass slaughter and the eradication of entire languages and cultures that took place as a result of the European expansion into the New World. Much of the expansion was fueled by madness and greed.

Here is an objective measure: "It goes on all day, day after day, a steady flow of supplicants coming into the tribal offices at Pine Ridge, which is in Shannon County, S.D., the poorest county in America, a place where unemployment hovers around 80 percent, where the per capita income is &#036;3,417 a year, the lowest in the nation, where two out of three people live below the federal poverty level."

Thus,

"Overall the results have not been entirely negative, and, one could argue, have been beneficial on balance."

On the contrary, the overall results (although not being entirely negative) are overwhelmingly negative. So let&#39;s be honest about our past and try to create a better future for as many living beings as we can.

I do agree with you that unforeseen technological developments might allow us to detect life bearing planets across most of the galaxy (It&#39;s just hard to imagine what they might be, at least for me.) I should remember that the detection of any extrasolar planets was considered laughable by many astronomers even 2-3 decades ago. I think Geoff Marcy even said that when he first started looking for planets in the 1980s, some astronomers laughed at him. Anyway, I am excited by and support the search for extrasolar planets.

What is your opinion on the Rare Earth Hypothesis, as this idea suggests we are probably alone in the universe?

Folkhemmet

[eburacum45]

Asteroid impact is not an answer to Fermi&#39;s paradox;
if major asteroid strikes happen on a civilised planet every 100 million years, the civilisation has on average 100 million years to

1/ expand into space to avoid such extinction events
and
2/ develop an asteroid detection and deflection scheme.

I certainly recommend our own civilisation does both.

[GOURDHEAD]

What is your opinion on the Rare Earth Hypothesis, as this idea suggests we are probably alone in the universe?

My guess is that having a moon the size of the Earth&#39;s moon relative to the mass of the parent planet is rare for planets in the Goldilocks zone. Some have speculated that the Earth&#39;s moon helped life to move to land by the way it affected the tides which led to stranding critters in shallow pools and forcing them to alter their life style. I share that view but I don&#39;t consider it to be necessary; huricanes will suffice but take longer. I remember reading some time back that there is enough water in Earth&#39;s oceans to cover the entire Earth 2 miles deep if its surface were less bumpy. There are probably planets in this configuration that have evolved life, but I see Earth-like technology very difficult to acquire by such critters, although I expect us to find life on each of the Gallilean moons of Jupiter, and, except for Io, complex living critters. Aside from the Earth/moon relationship I guess that the Earth is not rare in characteristics that matter for the evolution of carbon based life.

The chemical affinities for the CHON elements, and others that support Earth type life, for each other drive a level of self organization in both pre-biological and biological environments that guarantees that the MW is crawling, swimming, walking, flying, burrowing, squirming, floating, etc., with life as are each of the other galaxies. Some of them are no doubt rocketing/sailing about the galaxy by now depending on when they got started and how many times their progress was interrupted.

[Tom2Mars]

I am partial to the concept that at the present time, it might just be us looking and thinking about the universe. And, if that&#39;s the case, it would be very important for us not to mess things up more than we have already.

The expanding advanced civilization may be us, so we should work a bit harder at advancing while we expand.

[albedo_1]

Originally posted by eburacum45@Jan 23 2005, 08:27 PM
Asteroid impact is not an answer to Fermi&#39;s paradox;
if major asteroid strikes happen on a civilised planet every 100 million years, the civilisation has on average 100 million years to

1/ expand into space to avoid such extinction events
and
2/ develop an asteroid detection and deflection scheme.

I certainly recommend our own civilisation does both.

With great respect I remind the author that the last major strike was 65 million years ago. Also, that a major strike can return the biological clock back to zero and it took 6 BILLION years to get to this point in our evolution. The 100 million year number is not something cast in stone but an all too flexible number that could wipe us out before we have identified it and get a defense in place to capture it.

Space rocks, be they stoney meteroids which explode before hitting the earth, known as bolide, or iron cored meteorites that can be either asteroids or comets have seriously altereted our planet.

It is postulated that a mars size object hit the primoidal earth causing much of the lighter material to be ejected. This coalesced into our moon. This also provided the deep trenches that allow the earth to have land masses.

It is also thought that several major biological dieout were caused by space rocks or the volcanism which can be caused by a large mass striking the earth.

I use the term astronomical enthropy to describe this phenomena. Astrological darwinism might be a good term to describe a cosmic induced biological extinctions.

Please noticed that I have tried to correct and further clarify my previous post. The readers generous use of the reply statment is much appreciated.

I would like to ask a question. what is more important then the very survival of earth that we all live on? Where are our priorities?

BTW: I have a blog that goes into this in much more depth. cosmicshootinggallery