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SETI Results By Scientific American
Paul Cobbaut writes "This http://www.sciam.com/2000/070 0issue/0700crawford.html is a link to an article on SA about Seti results so far. It discusses about why we found no ET yet, and provides more links." Very lucid and informative. Compare and contrast with a previous story.
Where can we get some?
Speaking for the Weak Assocation for Astronomical Phenomenas' Rights to Stomp Over Tiny Life Forms, I feel the need to clarify:
Would a sea of brain matter, filling a whole planet, count as "life", even if it were totally introverted, never communicating its thoughts to us in any way?
Would an astronomical phenomena, like chain reactions of exploding stars and matter condensing into new star systems, count as life, if it were self-sustaining, self-replicating and adjusting to its surroundings?
What scale, what view of life, and what structure must a thing be to be considered "life" or "intelligent"? Could we please accept some of our neighbors in this ecosphere as such?
I think, therefore thoughts exist. Ego is just an impression.
It is now well accepted that our particular encoding of base pairs in the nucleic acid chains is arbitrary. Whether the use of nucleic acids is necessary at all for reproductive organisms isn't known. Certainly some non-NA based molecules have been constructed which could be said to reproduce.
So don't be too DNA-centric.
FatPhil
Also FatPhil on SoylentNews, id 863
"SETI program is indicative of the fact that we really are alone in the cosmos"
We have only been broadcasting radio signals for about 100 years. There are not that many stars in a radius of 100 light years, so even if there is life somewhere in this universe, it is unlikely it sits in that 100 lightyear radius. That means, alien life can't have noticed us yet. Which means that they probably did not sent a signal back either.
Not that I don't think SETI is a waste of research money. Only a decadent civilization like America can afford to pump so much money into listening to background noise.
Oh, and about 'god', I think the mere fact that we figured out that life rose on earth so quickly after its formation proves that we can do without a god like creature pretty well. After all, there's nothing mysterious about how we figured that out, definitaly no lord's hand at work here. And suppose I'm wrong than it at least proves that the 'god' is not even close to the romantic character in the bible and comparable literature.
"... of the Bible are true in asserting that God made us in his image."
If he looks like me, he must be an ugly bastard.
Jilles
Did you have a look at the actual article? There is a nice diagram... More details in the article.
Looked at it, but I had to change the settings on my display to see the numbers on the left side of the graph, so I missed that graph on my first reading. It just starts at 10^10 Watts. That's 10 billion watts, effective radiated power. I can't see that any civilization short of the level of building Dyson Spheres would have that much energy to just throw around.
I disagree with the implication that a higher level civilization would be transmitting that much power. We've gotten much more efficient with our bandwidth and power utilization, I have no doubt that a more advanced civilization would too. They probably have to deal with finite resources, just as we do.
But I think that this establishes that whoever is out there, they have to be trying to talk to us. We won't hear their analogue to TV or radio.
Adaptation is the key. Dinosaurs had their chance, 140 million years and the first major disaster comes along and wipes them out. It doesn't matter if it was an asteroid or time traveling big game hunters. Unless you develop intelligence, your ability to adapt is limited to your genes. Something WILL happen, it's just a matter of time.
Rare event three: birth and procreation of mutated ape of sufficient intelligence to create civilization. This ape was an omnivore: hunter killer explorer and able to exist on plants as well - a land animal; a social animal but not a herd dweller.
It's possible that being an omnivore is required to develop intelligence. We really don't know. It's also possible that we had cousins who developed intelligence along the same lines as we did. Simply because they're gone now doesn't mean we're the only ones EVER to develop intelligence.
The existence of a very few brilliant individuals; remove 20 or so people from history and we never develop technology. Remove the printing press and everything changes, remove Isaac Newton and everything changes dramatically. Who knows what things we have failed to learn for want of a person to show us the way?
Yeah, remove the radio, who would of invented it? Well, I guess Tesla would of. Ok, how about the automobile? Oh, yeah, at the time there was several people working on it? I don't believe that 99.9% of the human population wanders around without a thought in their head, and that single geniuses come along and bless us with their ideas. Ever notice when something new comes out of the labs, two other labs are also working on the same thing, and many many people have thought about that product? OCCASIONALLY someone jumps ahead and comes up with something good, but given time the 'average' thinker would have come up with it.
One of the aspects of intelligence is coming up with the correct answer more quickly. The inventions and scientific achievements you mention are created by geniuses simply because they were able to think of, and develop the idea first.
Democrats or Republicans. They are both taking us to the same place and they are not afraid of us anymore.
Maybe most civilizations don't last long after discovering radio communication. It seems like our candle has almost been snuffed several times in the last century.
First of all, life does not require 2 "matching pieces of genetic material". Clearly, RNA/DNA are highly evolved. The origin of life requires auto-catalytic systems (a chemical reaction whose products catalyze the reaction). These reactions then "evolve" so that they become more efficient and accurate, and ultimately become as complicated as a cell. Secondly, it is not likely that the arrangement of amino acids into a chain ("polymerization") just happened in primordial soup. People have specualted that water droplets in clouds, surfaces of charged minerals (iron pyrites or fools gold is currently favored) form areas more conducive to polymerization. Also, lipids (fatty acids which are the constituents of cell walls) spontaneouly for membranes in water, thus producing concentrated areas where certain chemical reactions could be more likely. The origin of life is a highly complicated topic, but biochemists have learned a surprising amount. For a good intro, see "The major transitions in evolution" by Maynard-Smith and Szathmary. As the Sci Am article pointed out, it seems that the origin of cellular life may actually be very easy, based on the fact that it seems to have happenened so quickly on earth. However, for 3.5 of the estimated 4 billion years that life has been present on earth, life was unicellular. The difficulty is the origin of multicellular and intelligent life. ' Vish
The sciam article leaves out a fifth possibility as to why no extraterrestrial civiliations seems to be broadcasting strong radio signals: There is something nasty is out there that hunts and destroys emerging civilizations.
Consider the possibility that one rather paranoid civilization wants to make the galaxy "safe" for later colonization. So they release a bunch of self-replicating planet killer probes. The probes hunt for radio signals from potentially competing civilizations. When they find one, they kill it before it has a chance to develop interstellar spaceflight.
This is basically the plot of Greg Bear's novels The Forge of God and Anvil of Stars. We could be like a babe mewling in the forest, calling down the wolves upon us.
I believe we can all agree that the first step of space travel is 'hard'. Getting off of your home planet and into orbit, much less escape velocity is difficult. It involves the control of *large* amounts of energy. In order to be truly spacefaring, you need to do this not a few times, but regularly. One can infer from this that very-high-energy technology is widely available in a spacefaring civilization.
Here on Earth, we don't really qualify as a spacefaring civilization, yet. We're close, but not *quite* there. At the same time, we're awfully lucky that we survived the Cuban Missle Crisis, and we just about punched out with WWIII when KAL-007 was shot down. (There was a lot of behind-the-scenes happening, then.)
I assert that a species that doesn't have a pretty good lid on its impulses, and that includes the human race, at the moment, will likely destroy itself once the wide deployment of the very-high-energy technology need to be spacefaring happens. We've survived nuclear power thus far by luck and by restricting deployment.
Most of our species is not fit to live in a nuclear era. We don't yet have the energy technology to be truly spacefaring, so this situation may well get worse before it gets better.
We need to grow up, more than a little.
Isn't this part of what the Star Trek civilization is about? So many people complain about ST-TNG talking the enemy to death, but if the first impulse was to always come out with blazing guns, how long would the Federation really last. I would instead argue that the Klingons never would have become truly spacefaring.
This presupposes human psychology. But I'd argue that the same is true of any life that arose in the Darwinian model.
By this reasoning, any species that has become truly spacefaring understands the problems of becoming a 'mature species', and is almost by definition non-intervening.
By the same token, we're having population problems even now. I'd also assert that we're going to have to have solved our uncontrolled breeding urges before space travel is truly viable. That further stacks the deck in the 'non-interventionist' camp. The "colonize the galaxy" model assumes expansion and population increase are limited only by transit time, and not by intelligence.
I don't know what the breeding and colonization speed of a mature spacefaring culture would be. It may also be that we have unknown links to Earth. There may be trace element atmospheric combinations that are unique to Earth that we depend on. Maybe as a species, we're infertile without that great big Moon in the sky. Maybe in order to colonize, we've got to learn to terraform, too. Sounds like a good reason to get to Mars with a permanent presence, to me. Explore our own biological limits.
The living have better things to do than to continue hating the dead.
See: Misconceptions Regarding SETI, Dyson Spheres and the Fermi Paradox
The bottom line is this -- nanotechnology enables the transition from pre-Kardashev-Type-I civilizations (us) to post-KT-II civilizations in decades. Such civilizations are resistant to almost all hazards on galactic scales and will thus be the dominant form of life in galaxies. If we are typical, it only takes a few hundred years to evolve from the discovery of the laws of physics to reach KT-II levels. KT-II civilizations survive for trillions of years. Unless the evolution of intelligent life is very, very difficult our galaxy should be dominiated by KT-II civilizations (Dyson shell supercomputers, a.k.a. Matrioshka Brains) with thought capacities in excess of a trillion trillion times the human mind.
Intentional communications generally occurs between entitites of approximately the same capacity. As we are at the sub-worm level in comparison to KT-II civilizations, they will not be directing communications at us. Non-intended leakage communications could be detected by SETI out to a few dozen light years, but we should be looking in the MHz frequences, not in the GHz frequencies. Therefore SETI@home is a waste of CPU cycles.
Interstellar travel is possible (the British Interplanetary Society Project Daedalus Study showed that). It is however pointless. The speed-of-light delays and communications costs for large volumes of data, mean you get little benefit from colonization. You do not want to become larger, you want to become smaller (or at least work very hard to minimize propagation delays)! The fact that KT-II civilizations can each build billions of lunar diameter telescopes makes rationalizations for interstellar travel difficult (why go "there" when you can "watch" there?). You also don't go very far, because "there", by the time you arrive, may not be there anymore (a closer civilization may have occupied the location). Arguments that we should colonize the galaxy in a few million years fail to understand that the rate of expansion is not limited by the speed-of-light but by the time it takes to dismantle planets, gas giants, brown dwarfs, etc. and turn them into something useful. It isn't the stars that are desirable to KT-II civilizations, it is planets with heavy metal abundances that "happen" to be on courses around the galaxy that these civilizations find attractive.
It is worth noting that the gravitational microlensing results, suggest that our galaxy is surrounded by ~200 billion "objects" of masses around 0.3-0.5 Msun. Astronomers are currently unable to provide an good explanation for what these might be. The best current guess is primordial black holes. (Of course most of the astronomers involved assume the universe is "dead".)
Comments by Verteiron, regarding the use of radio are absolutely correct. Given the capacities of KT-II civilizations, they are going to be able to build very large telescopes that can detect any other KT-II civilizations. If they want to communicate, they will do it using tightly focused lasers, probably in the blue or UV regions. This minimizes photon (energy) loss due to beam spreading and allows the highest data rates.
The Scientific American article (which, by the way, was from a previous issue. If you are not subscribed, you are really missing out) mentions a rough classification of alien civilizations (see sidebar to the main article). Type I civiliations (like ours) have the resources of their home planet to use in sending out EM signals. Type II civs have the resources of the entire system (the solar system, in our case) for signals, and Type III have the entire galaxy to use to send out EM signals. If Type III civs were out there and sending our radio beams, we would know by now. Nearly the same for Type II, so now we are looking for Type I's, who are doing pretty much the same thing we are - sending out narrowly focused beams, sweeping the sky, or just leaking out signal (radio, TV, whatever).
The assumption that some of the signal would leak out or be intentionally aimed at us has guided most SETI projects. However, is this really the case? In the last century, we may have had unfocused EM signals spraying all over the place, but for how long? It appears that our communication channels are starting to become more focused and efficent through the use of cables and focused, line-of-site EM. Even cellular phones, which still use EM propagation in the air, are short-range devices. How many of the products sold today would, in normal operation, produce signals detectable from Pluto, much less from light-years away? With commuinication devices heading for higher-bandwidth applications, I don't see this trend abating. I can imagine, by this time next century, the whole planet is using cabled or focused communication, so that the aliens would have to wander between the Moon and Earth to discover a narrowly focused communication channel. They may notice runway lights first.
This reasoning may eliminate any hope of discovering everyday communication signals from alien civilizations. But we should still search, in the hope that other civilizations are as interested in making contact as us. We have to assume that their scientists are thinking the same way we are, and are searching in "logical" bandwidths for good carrier signals, as well as transmitting powerful signals on these channels. Although we may be looking in the wrong place now, eventually we will have the funding and technology for powerful, broadband searches across the spectrum. At the same time, we may just be lucky and find ET tommorrow.
Agnokapathetic
It's a combination of agnostic and apathetic, as in "I don't know and I don't care."
And what is it about so many (not all) Christians, that they can't understand that you don't need a vengeful bogeyman looking over your shoulder to act decently and respect other people?
Stop by my site where I write about ERP systems & more
Will an intelligent species inevitably develop technology? Was it inevitable even for us? A look at our own history tends to throw some doubt on the assumption.
Why did human technology develop when it did? Greek philosophers had measured the circumference of a round earth, deduced the existence of atoms, and figured out that it was us who circled the sun. In many ways, they were more scientifically advanced than the European culture which finally birthed modern science. Two thousand years before Columbus and Galileo, Greece had all the pieces. Why didn't it put them together?
Chinese culture also birthed many "modern" technological advances -- from gunpowder to paper and the printing press -- and spawned several "proto-scientific" revolutions, yet they also never quite put the pieces together.
For nearly a thousand years, while Europe wallowed in the Dark Ages, Arab philosopher/scientists were the sole guardians of Greek philosophy. They had all the pieces Europe had lost, yet they, too, failed to birth a scientific revolution.
How and why did Europe finally pull itself out of its malaise? And what was the key which allowed it to do what other cultures with similar or greater potential had failed to do? It certainly had little to do with the 16th century's scientific knowledge -- which lagged behind both Arab and ancient Greek philosophers'.
It has been argued that the key which finally unlocked modern science was not a scientific discovery, but a religious belief. What early modern European culture possessed that others had lacked was a belief that the universe was fundamentally a place of order. After all, a search for the laws of order presupposes a belief that order exists. And it was Christianity which provided this missing link. The God of the Bible was a God of order who would necessarily create a universe in His own ordered image. It but remained for humans to deduce what that order was. It was this notion of the universe as a fundamentally and necessarily ordered place which had escaped both Greek and Arab philosophers, and which finally provided the spark which ignited the smouldering tinder.
I mention this not because I find the argument compelling, but simply because it illustrates my point: that science and technology are far from being inevitable offsprings of intelligence. Sixteenth century European philosopher/scientists were neither more intelligent nor more scientifically advanced than their ancient Greek forebears; in some ways they had in fact taken several steps backward. Science might easily have sprung from a 5th century BC Athenian womb, but it didn't. In fact, it might easily never have have sprung forth at all.
We may indeed be only one amongst hundreds or thousands of intelligent species inhabiting the cosmos. It may only be our technology which is unique.
Lee Kai Wen -- Taiwan, ROC
There is a BIG problem with the current SETI projects. The main one right now, the setiathome project (in which I am participating) is that it uses the arecebo telescope which can ONLY detect STRONG signals beamed AT US (so to speak, at least in our direction AND for a prolonged period of time).
If any project is going to find ET, it will need to be VERY sensitive and capable of detecting incidental emissions of radio/radar. In other words, it would have to be capable of detecting us from a sizable distance...as we do NOT broadcast in such a way to say "Here we are! Here we are!. As a matter of fact, as we get more technologically advanced, our emissions go down. We acquire narrow band, tight beam, laser transmission, low power-high efficiency transmission systems. None of these are conducive to detection from interstellar distances.
Setiathome REQUIRES (from an ET) a large, high-power, dedicated transmitter that happens to be pointing our direction at the right time in history. Hell, some culture, which must be rare in itself, could have been broadcasting in our direction throughout the dinosaur era, then after a few thousand, or even millions of years, given up and turned their transmitter in another direction or turned it off.
It seems odd to assume that ETs would be inclined to build such large dedicated transmitters merely as a beacon of their existence, and maintain them for hundreds of thousands of years or longer. This isn't what WE'RE doing. We are not even embarked on the eventual program of doing this. It seems odd that given our non-propensity to SPECIFICALLY broadcast our existence, that we should assume that others would. Speculation beyond our own species is PURELY speculation with no grounding in fact.
That all said, I would say that life is abundant, but that technologically advanced civilizations are extremely rare. If it weren't for a certain chance meteorite encounter some 65 mya, the dinosaurs would STILL be the likely dominant life form on earth. Even given the meteorite, if it were to be repeated, it is unlikely that humans would arise again. There is no evolutionary drive toward technological civilizations. If it weren't for a few chance events in the Far East, Middle East, and West in prehistory/early history, WE wouldn't be a technologically advanced civilization today. The native Americans, Aborigine Australians, the Celtic (and other) tribes of Europe, etc, would not have changed much from their past lifestyles and technology.
Chance events, unrepeatable on Earth, led to what we are today. I would doubt that such chance events happen all the time, certainly not to the point of leading to technological societies all over the galaxy. It is certainly possible that there are other advanced civs in our galaxy, but it could be only one or two other than our own. ...Or what if there is ONE technologically advanced civ (on average) in each galaxy at the same time? There would still be billions of such civs in the universe but they would be forever seperated by time and space, each living in their own galaxy filled with planets "peopled" by single-celled, or simple multi-celled organisms. Lots of places to colonize and study, given time, energy, and money (in whatever form they use). There may even be a host of stone-age civilizations all over each galaxy...but there is no reason to presuppose that each MUST develop into advanced technological societies - ever.
The setiathome project is a worthy test-of-concept project that just MIGHT (slim chance) find something. The projects more likely to find anything, however, haven't even been started yet. They require the best, most sensitive receivers that can detect an incidentally emitting civilization (detect their leakage) such as one like our own.
In Bushworld, they struggle to keep church and state separate in Iraq as they increasingly merge the two in America.
You make some huge assumptions in support of your points:
1. "Such civilizations [KT-II] are resistant to almost all hazards on galactic scales and will thus be the dominant form of life in galaxies."
All civilizations will always have to deal with self-generated hazards such as war (between themselves and other "alien" races), environmental degradation, and political strife. The greater their technology, the more terrible their weapons could become. You mention nanotechnology as a conduit to upward transition, yet there are scenarios, such as those presented in Kurtzweil's "The Age of Spiritual Machines", where flawed nanotechology could wipe out the planet, or deliberately designed nanotech weapons that could selectively destroy organisms based on genome.
No civilization is immune from self-destruction or competition with others.
2. "KT-II civilizations survive for trillions of years."
Given the universe is 8-12 billion years old, that's a pretty bold statement!
2. "Intentional communications generally occurs between entitites of approximately the same capacity. As we are at the sub-worm level in comparison to KT-II civilizations, they will not be directing communications at us."
Are you stating that If a KT-II civilization is aware of our existence, then they likely won't attempt to communicate with us? And although they might not communicate with us, we won't intercept any of there transmissions? Let me propose a scenario: Suppose there is a KT-I civilization on the path towards KT-II, that is grappling with the question "is there life out there?" To solve the answer, suppose they set up a listening system to catch wayward transmissions. Furthermore, they also decide to "talk" to the cosmos by blasting EM energy at likely candidates. What would the chances be that they could chose an enhabited system that was similarly listening? Another statement you make that could be clarified is why should we be listening in the MHz region?
3. "The fact that KT-II civilizations can each build billions of lunar diameter telescopes makes rationalizations for interstellar travel difficult (why go "there" when you can "watch" there?)"
In a universe dominated by KT-II's, none will have the desire to conquest, travel, colonize?
Great men in history are as rare as are great players in a sport. What would the Chicago Bulls have been without Michael Jordan? Well, we ran that experiment - the answer was a good solid above average professional basketball team. Jordan elevated them to the level of world beater. You don't replace a Michael Jordan. Sure there are plenty of others attempting to do the same things - THAT DOESN'T MEAN THEY CAN.
It infuriates mediocre thinkers that they can't think as well as great thinker can. Sorry about that, it infuriates mediocre athletes that they can't play in the NBA.
I'll state it again: great men are rare singularities - their achievements are not reproducible by others.
I particularly found the comments about Newton amusing. John Maynard Keynes denigrating Isaac Newton is like a modern day 6' NBA bench warming guard denigrating Wilt Chamberlain. Keynes must have been feeling particularly bitter and envious the day he said that.
By the way, people denigrate others in an attempt to tear those others down to their level; it is an attempt to look good by making others look bad. Isaac Newton would not have denigrated John Maynard Keynes; he would no more have said anything about him than Wilt Chamberlain would have found it necessary to comment on a six foot bench warmer.
I think all people are equal - but they are not all identical. People who are outstanding intellectually accomplish things that others can't. Sorry about that, but the world works that way.
Unfortunately we don't have the luxury of assuming there's a better means of communicating that an advanced society would use over radio. We can't just play the part of the indians and assume neighboring tribes have advanced beyond the point of smoke signals, so we should give up looking for them and sending out our own.
We have to assume that our view of physics and technology is correct and work off of that assumption. If we wish to detect neighboring civilizations or be detected by them, our best (and, really, only) means for doing so is by radio waves.
Other advanced civilizations will not only transition quickly from narrowband RF to using either spread spectrum or advanced techniques we don't know how to look for, but will also certainly deploy compression and cryptography to secure their transmissions. We are certainly headed in this direction after only a few decades of promiscuous broadcasting. This certainly makes SETI@home's job much harder.
They're receiving those I Love Lucy broadcasts, but they've been modded down.
if it ain't broke, then fix it 'till it is!
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
Note that the majority of cell phones in use today use digital CDMA spread-spectrum encoding. There are several benefits to this technology, which was originally developed for military use. CDMA transmissions are highly resistant to noise interference; are hard to snoop; and are very easy to hide in background noise. If you don't know what to look for, you won't see it. There's no intensity spike at any frequency.
This has been known for decades. It's entirely possible to foresee that all of our radio communications may use this technology in a few more decades' time, due to its benefits. This considerably increases the difficulty of anyone randomly discovering our existence by scanning our spectrum.
Giving ETI's credit for as much cleverness as we have, we are trying to find a ET civilization radiating within a few decades of its technological awakening.
Since the xxAA's seem to think that these US laws apply all over the earth (like Norway for example) why should they be restricted to this planet?
All opinions are my own - until criticized
just to play devil's advocate, if you say that intelligent life may be super-rare, yes, the dimensions of space and time make it possible, but what is the probability that ANOTHER intelligent species arose *locally*, that is, within a meaningful locality. Intelligent species arising 5 billion years from now, or 5 billion light years away, may as well not exist, they may as well be in a different universe. Most dreamers believe that we will one day master faster than light travel, and populate our galaxy, but few believe that within the scope of the existence of Homo Sapiens, that other galaxies will be contacted, let alone travelled to and colonized. The distances involved are nothing to a dreamer, but if you've got ANY realist in you at all, you realize that other galaxies are simply way too far away.
So as the probability of intelligent species arising declines, the probability of their MEANINGFUL existance declines as well. If there are no others within this Galaxy, we might very well just hang it up. Of course, we'll never know until we've explored every speck of dust in the universe, not only for signs of current life, or evidence of the past existance. There's no way anybody can ever accurately say "there is NO other life in the universe".
if it ain't broke, then fix it 'till it is!
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
On the contrary, I think looking for planets is a good start.
Other things searched are meteorites (many of which can easily be found in Antarctica, lying on top of the ice!) for life traces and radiowaves (Is there a Natalie Portman on other worlds and are they doing anything this weekend?)
There are only so many means available until we actually send a craft to one of these extraterrestrial bodies and and look around. As much as Tommy Lee Jones joked about the tabloids being the best place to look for alien sitings, it would seem with all the coverage these things have, SETI should be focusing on trailer parks first. Maybe find some alien sonic screwdriver or sparkplug on the outskirts.
The scope of time is the most daunting. Only for ~100 years have we made enough noise and emitted enough light to be seen from space, nearly doing ourselves in back in 1962. Not even an eyeblink in the history of intelligent life. Odds may be that intelligent life will be found after it's already dead. I think that would be a pretty good wake up --
"SETI reports the sitings of large, bright flashes of light on planet x, followed by total cessation of radio emissions."
Personally, I think it would rock to find a planet ruled by dinosaurs and feed Britney Spears to one 8)
Vote Naked 2000
A feeling of having made the same mistake before: Deja Foobar
It appears that is the way we are heading, in a matter of decades. It could be that detectable signals are only sent for a very very short period in the time of a civilization.
If other intelligent, mechanically capable life exists in the universe, then why don't we see them?
Forseeable advances in technology include self-reproducing machines. (Call Von Neumann machines after this argument.) Other forseeable advances include our sending these machines into space to colonize other environments. At current rates within the century, probably within decades.
Even given the speed of light problem, within a few million years our machines likely will have colonized all corners of our galaxy.
The odds of intelligent life achieving technology twice at essentially the same moment are pretty low. Given what we expect ourselves to do, it is a pretty safe bet that if we locate extra-terrestrial intelligence it won't be in our galaxy, it will be in another.
:-)
Cheers,
Ben
My usual seat in the cluetrain is at A HREF="http://pub4.ezboard.com/biwethey.ht
Everything that is being done in SETI assumes modulated RF. What if after a while using radio, other civilisations simply move to something else like quantum coupled whatevers?
If the time that a civilisation uses RF signals is limited then so is it's exposure. This could even be a feature if there are other unfriendly civilisations out there.
Nah, SETI@home is interesting and I have about 430 workunits. There is still a time where a cvilisation is visible in the RF spectrum, even if it isn't the whole time.
Where would we all be without the USofA?
The machine gun and rapid advances in military science could have led to a European dominance and freezing of technology development.
Right! The fact that Europe was progressing very fast in the 19th and early 20th century does not lead to a freezing of technological development. Au contraire!
I'll do it for cheesy poofs.
There are theories out there that suggest planets and evens moons have life on them already but they are with the crust of the planet. I am not talking about the Lost World. I am talking about bacterial life that was formed from with the earth and then if the condtions outside were ok they came and formed into more complex lifeform the answer may not be above but below
Does it necessarily follow that He must do so? Perhaps He simply chose not to.
If his point was to maximize the good in the universe, then he would be obligated to create as much life as possible to interpret and appreciate the good, and give thanks to its creator.
If his job was just to create it and watch, he's doing a bang up job.
--
+&x
seti@home won't find alien life because it is just a distributed MP3 compression job on the Aricebo astronomers CD collection.
Bob.
The point is for such a CD to be a rosetta stone. While I can't say that I think like an alien, I have to imagine that a species that could intercept such a device would A) be curious as to what the CD was, and B) have the technology to look at really small things. So they put it under an electron microscope, and ta-da! you see a long grove whith markings on it.
Now, while aliens probably don't use ASCII, if they have anything that we would consider intelligence and technology, they will figure out they are looking at a binary code--after all, that is the second simplest numerical system possible, after tick marks.
From that point, whether an alien will be able to reverse engineer ISO9660 is up for debate, but one of the most important things is that it is undeinable proof of an intelligent species. Of course, so is a space vehicle. Anyway, if it were ME discovering that CD, and finding that it had binary encoded data on it, I would certainly work real hard to decypher it. Honestly, if a species can unravel quantum mechanics (another must for high technology as far as we know), they can figure out how to read a CD.
Evolution concepts are not flawed, especially if you've put more effort into studying them than switching on the Discovery channel. Evolution is a more complex process than just the fittest surviving. Biological organisms strive for homeostasis, the point where they function best at. If you run around and start burning up calories your body will sweat and dialate capilaries in order to shunt the heat produced by the extra expenditure of energy. This is merely a simple example of an organism adjusting it's internal processes to maintain homeostasis. When evironmental conditions around an organism change which cause it to adapt and stay in such a state that new set of biological criteria will be addended to the DNA of said organism and eventually get passed onto progeny. After a few generations the adaptation will become a staple part of that organisms characteristics. Darwin originally proposed that random mutation was the key to evolution but he did not fully grasps the sub-cellular chemistry of biological organisms. Humans are not misfits of any sort. The monkeys living on the coast of modern day Somalia started moving into the water for short stints to gather food and escape from predatores. Evidence of this can be seen in the slight webs of skin between our fingers and our downwardly sloped noses which facilitate surface swimming. Such factors led to us having oposable thumbs and a greater adeptness for using our brains for problem solving (like using rocks to crack open shellfish or using stucks to pry shells open) when they began to stray from the water they kept their afinity for tools. From there we see an increased use of tools as the homo genus spread around adapting to more and more areas leaving their monkey cousins behind. Over the years we lost our fur and developed more complex brains due to our increase use of tools. We first use of technology is what retarded some of our more primal characteristics such as claws. We didn't need technology to survive originally, we've just built our society around it and couldn't fathom not using tools to asist what we left behind on the shores of Africa.
I'm a loner Dottie, a Rebel.
A light year is several trillion miles in linear distance, the cloest star to Sol is Proxima Centauri which is about 4.2 light years. IIRC the cloest star to Sol with planets is 30 or so light years away. The Drake equation states theres millions of intelligent civilizations in our galaxy alone (or so). I support this but I also realize the immense size of our Galaxy and our Universe. We've been searching for ET life for a mere speck of time and have only been sending signals out long enough to extend to less than 100 light years. We're not the fucking first and not the fucking last, we're just so far from everyone else that it will take centuries to first make contact, by that time some of our orders from Amazon will be ariving so it will be a time of great rejoicing.
I'm a loner Dottie, a Rebel.
We've seen the spectacular results so far of the researchers finding Jovian sized planets orbiting at Mercury sized orbits. So far, they're detecting really elliptical orbits, and at least some of the speculation is that these planets formed further out and migrated in, cleaning up the dust and the little planets. Doesn't paint a happy picture for the [percentage of Sun-like stars that have an Earth like rocky planet in the water zone.] We may have a galaxy with lots of Sun-like stars but relatively few Earth-like planets. Has anybody seen an article that relates the 50 or so found planets to the number of stars searched? Has anybody seen an article that extrapolates from this data to how what percentage of stars have nice round orbits with nice blue planets ruled out?
Peace.
The only egotism here is yours fuckface. You're talking as if theres ten civilizations in the universe and they are all wildly different. A conservative run-through of the Drake equation numbers the total number of civilizations in the galaxy to millions. Thats more civilized cultures than have ever set foot upon this planet in known recorded human history. Many of the cultures here are dissimilar in only a small handful of ways to other ones. If we apply such a pattern to the theorized galactic civilzations, there are thousands upon thousands of cultures similar in many ways to us which means they're going to be using RF for long distance communication. And if you weren't a complete idiot the fact that the radio waves being listened to by SETI have been carefully chosen. Said frequencies are those that pass through the Earth's radio "window", those frequencies that pass through all the layers of atmosphere and actually hit the ground. A planet like ours supporting life civilized life forms like us would have a radio window just like ours. If we were sending a signal out to be seen by the rest of the universe we would send it in said radio window band. You should also be aware that the microwaves that cook your food are RF which stands for radio frequency. You also might want to be aware that it was Marconi and not Morse that did alot of the work in radio transmission.
I'm a loner Dottie, a Rebel.
If you want to communicate to a vast audience you choose the most esoteric medium you possibly can because you can be pretty such that it grants you a large target audience. If you're sending a message to the universe saying "Here I am" you're going to send your message in a way everyone can understand. Take Contact by Carl Sagan, the Vegans sent a repeating signal of prime numbers on a radio frequency to get our attention. That is a good way to grab a listener's attention. A bas way would be to use some exotic form of communication that requires a fantastic mastery of a certain form of technology in order to even see. Actually very recently some astronomers took this idea to another level and have begun to search for lasers being used to communicate. Bright pulses in an easy to spot part of the spectrum (something that wont be confused as a stellar phenomenon). SETI's success will depend on patience, ingenuity and vigilance.
I'm a loner Dottie, a Rebel.
But the problem is that we're not transmitting such a signal. So if the above is accurate, we're basically looking for signals from civilizations quite a bit more advanced, or who place more emphasis on communicating with ETs, than ours. There could be thousands of civilizations a lot like ours that aren't detectable, most of whose members could care less about communicating with ETs and thus aren't putting any effort into sending out a message.
You're thinking of colonization the wrong way. Instead of sending humans and animals to distant planets it would be a much better thing to send a genetic legacy to the far reaches of space. There have been those that have proposed that we are indeed the end result of inter galactic genetic seeding. Arthur Clark being one of those, in the Oddessy series the monoliths were evolutionary guidestones that would eventually get life on Earth to where it needed to be. Thats how you colonize a galaxy.
I'm a loner Dottie, a Rebel.
The chance that a "Prime Directive" not to interfere in other civilizations is part of the cause is actually more likely than at first glance. Assume that civilizations arise at the rate of one every few thousand years. This means that the first civilization (Civ A) to arise has that amount of technological head start over the next (Civ B). At this point, we've hit the Clarke "Magic" level of technology for A over B, where civilization B could be stepped on like ants by civilization A.
Thus, we don't need every civilization to decide not to interfere. We only need the first to decide on a Prime Directive and decide to enforce it.
That reasoning doesn't work.
This logic simply doesn't work.
Perhaps, but see we don't care what they're using now. All they had to do is blast EM noise for a few years so that so that we pick it up. To use your analogy, the aliens went from runners, to cell phones, skipping smoke signals completly. It just doesn't strike me as that plausable.
I'm lookin' for you, dad, I'm even running the Seti@home client on several dozen machines at work .. why won't you talk to me, dad! Why don't you ever call?!
N = N* fp ne fl fi fc fL
The equation can really be looked at as a number of questions:
N* represents the number of stars in the Milky Way Galaxy
Question: How many stars are in the Milky Way Galaxy?
Answer: Current estimates are around 200 billion.
fp is the fraction of stars that have planets around them
Question: What percentage of stars have planetary systems?
Answer: Thanks to advances in technology, new planets are being discovered every month. Within a few years we may have a reasonably accurate estimate. For now we'll say 20% (a standard estimate given my many including Frank Drake).
ne is the number of planets per star that are capable of sustaining life
Question: For each star that does have a planetary system, how many planets are capable of sustaining life?
Answer: If you base it on our solar system you might say 3 planets could possibly support life - Venus, Earth, and Mars. There is also the chance that one or more of Jupiter's moons could support life. If our system is typical the answer may be between 3 and 5.
fl is the fraction of planets in ne where life evolves
Question: On what percentage of the planets that are capable of sustaining life does life actually evolve?
Answer: Current guesses range from 100% (where life can evolve it will) down to close to 0%.
fi is the fraction of fl where intelligent life evolves
Question: On the planets where life does evolve, what percentage evolves intelligent life?
Answer: Guesses range from 100% (intelligence is such a survival advantage that it will certainly evolve) down to near 0%.
fc is the fraction of fi that communicate
Question: What percentage of intelligent races have the means and the desire to communicate?
Answer: Who knows? Let's guess 10% to 20%
fL is fraction of the planet's life during which the communicating civilizations live
Question: For each civilization that does communicate, for what fraction of the planet's life does the civilization survive?
Answer: This is the toughest of the questions. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? If we were destroyed tomorrow the answer to this question would be 1/100,000,000th. If we survive for another 10,000 years the answer will be 1/1,000,000th.
When all of these variables are multiplied together we come up with:
N the number of communicating civilizations in the galaxy.
Send a sattelite into orbit around the sun. It unfolds some huge mirrors, capturing the Sun's light and reflecting it. Other's observing our star will notice the difference in brightness. As the sattelite rotates around the sun it reflects the light in one direction, just like a lighthouse.
Look at how we study stars now. Our star may look normal, let's try ot make it look abnormal. No matter how we communicate I think any civilization of any advancement will notice if a star begins to look 'different'.
Human civilization has only made technological use of radio waves for an extremely short period of time as compared to both the length of time we have had human civilizations and the length of time that humans have inhabited this planet. At the current rate of technological advancement, or even one half that rate, before we've even hit the midway point of the 1000 year duration of our civilization (according to the scale used in the article) we will be long past the "primitive" use of radio signals that we have employed over the past 100 years. To think that an advanced civilization is necessarily going to produce detectable radio signals is, in my mind, extremely short-sighted. But that's what we can look for with our SETI telescopes. And hey, I enjoy pitting identical machines running SETI side by side and watching the Linux box beat the Windows box by a couple of hours every time.
Windows is going the way of phlogiston...
How do you know that super novae aren't the results of alien wars?
There is a lot we don't understand about the universe. It might be that some of the strange things we see going bump in the cosmic night are the work of intelligence.
Slashdot monitor for your Mozilla sidebar or Active Desktop.
One of the major reasons that ET will prove so elusive is the fact that we're not only looking at narrow slices of space, on narrow frequencies... but we're also looking for a signal that may encompass a very narrow slice of time for a civilization.
Putting aside the argument that intelligent life is not the "goal" of evolution (which is also a very good thing to remember), let's assume that an intelligent civilization DOES evolve out there. How long are they going to use radio for communication?
I don't claim to know tons about the area of the EM spectrum we're currently searching, but don't you think there will be better ways to communicate?
Analogy: Two tribes in two valleys separated by hills communicate via smoke signals. This is, to them, not only the best, but one of the only ways to communicate. Yet, all around them, even passing through them, are our radio waves, from our civilization, carrying speech and music, microwaves carrying our voices... Is it really so hard to adapt this analogy to our situation?
For all we know, there could be civilizations all around us, communicating; we just don't have the technology to detect the transmissions.
End of lesson. You may press the button.
Thus, we don't need every civilization to decide not to interfere. We only need the first to decide on a Prime Directive and decide to enforce it.
It gets even more likely as we go farther back: if we assume a few million years between civs, civ A is now so overwhelming that it could do anything it wanted without effort. (To paraphrase a line from Gardner, "(They) had a billion years of evolution on humans. To call them godlike would be demeaning.")
Eric
"Seven Deadly Sins? I thought it was a to-do list!"
We're puzzled as to how some of the planetary systems we've seen recently have gas giants close to the primary, contradicting our ideas about the formation of planetary systems. What if they were moved? I'm not saying that I'd bet they were, but we're more likely to alter our theories about stellar formation than to say "Ah! The work of ET engineers!"
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
Unless intelligence is universally self-extinguishing at a certain level of technological development.
You are equating human intelligence with intelligence in general. Our destructive natures come from our predatory background rather than our intelligence. Other intelligences, following different evolutionary paths, would probably have a different set of hard-wired instincts, such as a strong flee instinct rather than a fight one.
It's a good thing, since we'd probably try to destroy any extraterrestrial culture we bumped into.
Or they'd destroy us.
********* sig: If you don't like the law, get filthy stinking rich, and buy a better one.
- are as rare as Crawford maintains, based on the unlikelihood that simple life forms evolve into more complex ones
- are in all probability very, very far away from our galaxy and therefore more difficult to detect by conventional means
- have been broadcasting (purposely or inadvertantly) in a different medium than the ones we consider likely.
For example, a truly advanced civilization may have learned how to propogate messages through "gravity waves" or the extra dimensions (six, IIRC) that superstring theorists postulate must exist, or using the "spooky action at a distance"property of quantum particles. And these are only the examples we know enough to guess at.Obviously we have good reasons to be searching the radio frequencies for signs of intelligence - after all, such frequencies are commonly emitted by all sorts of cosmic objects and can be used fairly easily to transmit messages over long distances. But perhaps the very fact that these frequencies are clogged already would lead other (more?) advanced civilizations to avoid them and look for other, clearer means of transmission.
Coupled with Crawford's theory that intelligent life has a low probability of evolving out of simpler life forms (i.e. bacteria or protozoa), and the follow-on assumption that such civilizations would thus be spread very thinly around the universe, this hypothesis could be a plausible explanation for why we haven't found anything yet. After all, we've only just started looking.
Was that out loud?
If flee evolved as dominant somewhere else, that would explain why they haven't come here...
"Those humans, there they go again, killing each other..."
"What for THIS time? Oil? Race? Religion?"
"No, I keep picking up something about a flaming troll..."
The Divine Creatrix in a Mortal Shell that stays Crunchy in Milk
The House Between - Original Sci-Fi Series
Here's some thoughts I've had about SETI:
Something I've never seen is any information about how powerful the extraterrestrial signals have to be for us to hear them- to do that, we need to know how much gain the receiving antenna has, what the sensitivity of the receiver is, and the intensity of the background noise. From that information we can get an idea of what sort of transmitters (at what distance) we're looking for. For example, a big radio station in the US is about 100KW, with antennas that point the signal more or less to the horizon. We make it a point not to send too much energy up- the intensity pointing straight up at the sky is many dB down from the main lobe. Just how far away could the Aricibo antenna hear a station that had an effective 1KW (isotropic) pointed in their direction?
Of course the Aricibo antenna doesn't listen at the frequencies of FM radio, it listens to signals in the microwave region (for SETI work, from what I understand). At these frequencies, it is even easier to point the signal from an antenna. Unless someone is broadcasting to us intentionally, I have a feeling we're never going to hear them.
There has been much talk about how we've been broadcasting to the universe- but at stellar distances, all those signals are going to look like they're coming from the same point, albeit diverse in frequency. But everything at the same frequency gets added together- and if you add enough non-correlated signals together- guess what: it looks like noise! Can our signals compete with the EM noise put out by the Sun?
Another thing: as our technology improves, our signals look more and more like noise, and we use less effective power- consider any sort of spread spectrum- the energy has been spread out over a wide area to combat interference, lowering the peak power at any one frequency. At the same time we're making improvements with our receivers so that we don't need to transmit as much power. It all ends up as more efficient use of what we have (more bandwidth for the same power) I can't think of any expanding intelligence that couldn't see the utility of that- so as an intelligent race expands, the overall amount of unintended radiation may not go up proportinately.
On the other hand, I support SETI- I've got it running on 4 machines, and I've completed over 350 SETI@Home work units. If we don't look, we won't find anything until they land on the White House lawn. These are just some things I've been thinking about.
It's a little premature to be saying even this, isn't it? We've barely started looking, and there's gobs of space and frequencies that we haven't examined yet. To proclaim failure at this point is not reasonable.
...phil
...phil
"For a list of the ways which technology has failed to improve our quality of life, press 3."
Note bene: this is called the God of the Gaps argument, and you've gone an excellent job of showing why it's a pointless position.
...phil
...phil
"For a list of the ways which technology has failed to improve our quality of life, press 3."
While I have no problem with your belief I can't help but note that religion is constantly losing ground to science.
The bastions of religion are all in areas which are unknown or "unknowable". As science begins to peer into these subjects religious dogma is shown to be innacurate or downright wrong.
Do religions or their champions collapse? No. They simply retreat back into less-explored regions.
>> The face that life on Earth arose so quickly after it's formation - about 500 million years later - is a sure sign of the Lord's hand at work.
Is it? We just don't know - and unless YOU are God you don't either.
My point isn't whether your statement is true or false. My point is that if science gets closer to the truth of this you will cede this ground and move onto some other "sure sign".
The first is the existence of moon of sufficient size to help create tides and provide a just the right amount of long term stability to the earth to allow life to evolve. Back in the sixties I read a book on the probabilities of life in the universe that pointed out the importance of the moon to life on earth. If current theories about the formation of the moon are correct the moon was formed by the collision of a mars size planetoid with the proto earth. That is a rare event.
Rare event two: the extinction of the dinosaurs by an asteroid impact.
Rare event three: birth and procreation of mutated ape of sufficient intelligence to create civilization. This ape was an omnivore: hunter killer explorer and able to exist on plants as well - a land animal; a social animal but not a herd dweller. Imagine for a second that the creature that sprouted first intelligence was a dolphin like creature or a cape buffalo type animal. In that case the course of intelligent life on this planet might have been very different.
The black death in europe. It has been pointed out that the decimation of europe's population allowed both the freedom to develop technology and the need for labor saving devices.
The existence of a very few brilliant individuals; remove 20 or so people from history and we never develop technology. Remove the printing press and everything changes, remove Isaac Newton and everything changes dramatically. Who knows what things we have failed to learn for want of a person to show us the way?
A long period of time without a life killing catastrophe of natural origin. A mild nuclear flare up from the sun - a major impact from a large asteroid - a 'nuclear winter' from a volcanic event, an ice age at the wrong time.
We may well be the only technological civilization in the galaxy - or even the universe. How sad, how terribly sad.
One of the assumptions of those who believe that SETI will yield a positive result (signal from extra-terestial civilization) make some assumptions about the probability of life springing up on other planets that may be incorrect.
We have all learned in elementary school that if you put some hydrogen, amonia, methane and other gases in a chamber and apply some electricty, that simple amino acids are formed. And the hypothesis goes, once you get amino acids, simple organisms are certain to appear. However, this may be an over simplicity of what really needs to happen.
One of the characteristics of life (as we understand it), is that a means for self replication of the genetic code is required. This requires two 'matching pieces' of genetic material, DNA and RNA. DNA on its own cannot self replicate - it needs RNA to complete this process, and the RNA must exactly match the requirements of the DNA to cause the self replication.
Considering that in the primordial soup, the random arraingement of amino acids join together (defying entropy since the universe in general tends towards disorder)to form an ordered chain of DNA,
AND
that an arraingement of amino acids join together (again defying entropy) to form an ordered chain that makes the complimentary RNA chain
AND
that they just happen to be floating in the primordial soup with sufficient proximity that they 'hook up' ( a significant statistical improbability)
THEN
you may or may not have a DNA chain that is capable of self replication, let alone one that is yields to a single celled organism, something that we would recogize as life, from which all other live could eventually evolve from mutations in its cellular division.
I am not implying that we are alone, just that the universe may not be "teeming with life" as we might like to believe.
The next probe will probably carry a DVD instead. Now how do we explain to the aliens why these "lawyers" are coming to "sue" them simply because they really managed to decode our discs.
All opinions are my own - until criticized
This assumes that ET societies evolve along similar lines to ours in terms of the balance of technology and ethos. History is full of nations where this is not the case. Israel, the historical kingdom, was far more advanced in theology than it's contemporaries. England frequently in government, Germany repeatedly in science, currently the USA in entreprenership. Why should it be assumed that this would not carry over to whole societies? Could a race like the Firengi exist (as in advanced technology but primitive ethics) ??
So long and thanks for all the fish . . . !!!
Of the ten commandments, these would be most objectionable:
1 No other gods before me
2. No graven images, etc
3. Something about a name and vanity
4. something about keeping a day holy
5. adultery is in the eye of the beholder
6. something about treating servants and wives as property.
But, then, I'm not exactly straight thinking, in your eyes-- since I believe that the "ten commandments" are the product of but one religion, and should not be posted in, say, courtrooms.
There aren't any other creatures on the planet even close to our intelligence. I know that Koko has been taught sign language, but does Koko have anything to say? Mostly it is "Koko good - give me a banana". If intelligence wasn't a rare mutation we would expect to see another instance of it in the 4 billion year record of this planet - we don't.
Point 4: The great man theory of progress. Eliminate Edison and tell me about MP3's. Edison's patent for the phonograph didn't have even a single prior art reference of any type that anyone could find. To claim that someone else would have invented it is specious at best. Why are they called Maxwell's equations? By your, and other people's line of reasoning the correct name would be 'electromagnetic equations which anyone could have come up with but chance gave it to this guy'.
The attack on the great men of history was created by a bunch of mediocre thinkers who can't imagine any other method of thought than their own. It is designed to denigrate and deny the existence of greatness and to exalt mediocrity. The idea is "If I'd been around then I could have come up with XYZ" Yeah, BULLSHIT, if you aren't a great thinker now -if you can't come up with great accomplishments now - what makes you think you could have then?
The other people who were working on a given 'idea' (if there are any others) all FAILED. There is no reason to believe that they would have eventually succeeded. We remember the ones we do BECAUSE THEY SUCCEEDED.
While the 'anyone would have done it' theory is all nice and Politically Correct it is not provable.
We study the great thinkers of history because they taught us different ways of thought - they had an influence on the way modern man thinks. They weren't a bunch of Cliff Clavins sitting in some bar spouting random made up BS. The supply of great men is very small.
I'll bite the bait - if your God is omnipotent, why do you place boundaries on his work by claiming that we, the lifeforms on Earth, are the only ones he made? It would occur to me that a truly omnipotent God would have created beings in his image lots of places. Everywhere would not be a problem, since he's also omnipresent. He just hasn't seen fit to tell us about it, or something, I don't claim to know how your God works. I see NO reason why believing in the Bible would exclude believing in extraterrestrial life - I rather think it would include extraterrestrial life because of the omnipotency. What happened to being humble before God? Your cocky claim that you know EXACTLY where his work ends is in glaring contrast to the humbleness towards an omnipresent/omnipotent God that the Bible actually teaches us.
Black holes are where God divided by zero
(One sq. km will allow you to detect an Earth-size planet, at a distance of 1 AU from it's sun, at a resolution of 1 pixel.)
You also want to place the dish(es) in space, to reduce noise pollution from unintelligent life-forms, such as humans.
(A reasonable starting configuration would be two dishes 500 miles in diameter, shielded by the moon from Terrestrial interference, and placed far enough apart to use interferrometry, etc, to guague distance and motion.)
Then, you have to use a practical time-base. Most modern radio telescopes use as long a time-base as they can get away with, to maximise signal gain. For SETI work, you really need the =SHORTEST= possible time-base your equiptment will allow, so that signals aren't smudged into the background.
Third, it's easier to detect complex, unstable atmospheres than it is to detect a signal, so using the absorbtion lines as a filter would help. This would avoid false positives, such as reflected signals, because ALL the signals you're looking for would need to be reflected in just the right way to appear to come from exactly the same distance and direction.
Lastly, assumptions about the nature of the signal should be avoided at all costs. Checking a few thousand, a few million or even a few billion channels in a very narrow band is really not going to have much chance of success. To carry out a SETI search, you must check several septillion channels, over a wide band, with checks for all usable rates at all frequencies scanned, with and without allowance for doplar on one (or both) ends, without excluding "random noise". (What may be "random", when examined over one interval, may stand out as "WOW! II, the Real Signal" over another. By recording the raw data, and examining it using a variety of methods, you stand a much better chance of locating a signal.)
Oh, and don't forget aliens with CB's, who only use the side-bands.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
SETI must count on one of two things happening to ET societies. First, the rare one which everyone dwells on. A neighboring civilization arises at very much the same time as ours and we pick up very similar to our radio signals from them.
Much more likely is that a neighboring society arises to a break point in the technological chain and freezes there. This break point is after radio is invented. Where it not for the USA's rapid growth and evolution in the late 19th and early 20th centuries (and Japan's rise in power), Earth could have hit one of these break points. Basic radio would not have advanced without American hobbyists screwing around with it in the first few decades of it's existence. The machine gun and rapid advances in military science could have led to a European dominance and freezing of technology development. If small power elites control technology and the technology is sufficiently advanced then such a breakpoint can be reached. Post radio break point societies is what SETI really looks for.
So long and thanks for all the fish . . . !!!
- the existence of moon of sufficient size to help create tides and provide a just the right amount of long term stability to the earth to allow life to evolve. . . That is a rare event
- the extinction of the dinosaurs by an asteroid impact
- birth and procreation of mutated ape of sufficient intelligence to create civilization
- The existence of a very few brilliant individuals
- A long period of time without a life killing catastrophe of natural origin.
I think that if the probability of intelligent life arising naturally is nonzero (i.e. there is no divine intervention or the like required), then it must have happened many times throughout the universe; the universe is simply too unimaginably huge for it not to have. However, intelligent life in a galaxy a gigaparsec from us is not terribly interesting; if that's our closest neighbor, then we might as well be alone. The interesting question is whether there is intelligent life close enough that we might be able to interact with it someday, and on that question we are basically ignorant. We have no idea how typical our own planet and solar system really are. We have begun to see signs that planets, at least, are not all that uncommon, and this is progress, but we have no idea how likely the coincidences that allowed technological civilization to evolve really are. Any attempt to generalize from the one example we have to the galaxy as a whole is mere speculation. Not that there is anything wrong with speculation, mind you, but we should take care not to confuse our speculation with fact.Granted, but is this the only stable configuration? What about moons around gas giants? What about configurations that don't occur at all in our solar system?
Why is this necessary? Who is to say that the dinosaurs wouldn't have spawned an intelligent race on their own, had they survived. Or maybe they would have died off for other reasons; the late Cretaceous is not the only mass extinction in earth history, after all.
We have no data on how rare this really is, nor can we be sure that something resembling a primate is the only sort of life that can develop civilization.
This is a very distorted view of scientific and technological progress. Closer examination of history shows that when the time for an idea is right, there are usually many people working on it independently. We remember the one who got there first, and we forget the also-rans, but that doesn't mean they weren't there. If Newton had died of the plague, others would have picked up the torch. Maybe we would have had to wait another decade or two, but physics would have developed, just the same.
Sure, but how rare is that, really? With only our own planet's history to draw from, it's hard to say, exactly.
Since we are too ignorant to predict from theory what we might find out there, our only recourse is to look and see what we can turn up. SETI is a crude tool; there are too many ways for it to fail to detect something that really is out there. For the moment, however, it is the only tool we have. Someday we will have space-based interferometers that are capable of resolving nearby planets directly, and that will tell us a lot more about how typical or atypical our own planet really is. And after that, who knows? We may never find out whether or not we are alone, but if we don't look, then we'll definitely never know.
``Sure the game is rigged, but don't let that stop you. If you don't bet, then you can't win.'' --Robert A. Heinlein
-rpl