Why Hasn't SETI Found Anything Yet?

Great Debates
41

Some of these remind me of MST3k:
“The Light from these credits originated well over 7000 years ago”-Mike …

I am forced to Agree with Shagnasty, unfortunately. I’ve always wanted to be around when contact was made, but the chances are against it - the Drake relation alone drowns out any hope for me. One can also see all this on the SETI homepage [ http://www.seti.org/site/pp.asp?c=ktJ2J9MMIsE&b=178911 ].

I also do have the same subconscious Xenophobic fear as some here: that if we actually were able, by some miracle, to contact some intelligent species in outer space and get them to respond, that it would be a detriment to our existence. To end with a quote Tom Servo: “… and This Island Earth can be yours, if the price is right.”

42

YEssss, they’ll want to see our ‘historical documents’. :wink:

43

What if the aliens simply don’t care if there’s intelligent life or not? They’re the equivalent of the feudal Japanese, perfectly happy on their planet, not feeling any desire to branch out. Maybe they know about us, maybe they don’t, but either way it doesn’t matter to them. And as for why no signals, maybe they’re telepathic or communicate by scent only. Or maybe they’re all semi-autistic (from our perspective) and so don’t feel the need to communicate much with anyone.

If there are aliens they are going to be much more weird and unknowable than the aliens on Star Trek or even Contact, that’s for sure. Their thought processes won’t be anything like ours; they won’t necessarily be superior, but they will be different. They won’t have the same senses. I think it is really unlikely that we’ll ever communicate with aliens even if we do find them just because of that; we assume they can hear and see but there are tons of other possible senses a being could have, and all of them could be incompatible with receiving radio signals from another world. (For instance, being which communicate via taste and smell could not send out a signal to another world.)

I also find it funny that some of the hard atheists on this board are super-sure about the existence of ETs, so much so that they are in favor of putting government money into the search. (SETI is gov-funded, right?) I think it’s highly probable that there is life on other planets too, but you can’t prove it just by citing the vastness of space.

44

Another name for the OP’s question is the Fermi Paradox, or “Where is everybody?”

Fermi paradox

45

A lot more.

An oft used set of estimates is that there are 100 billion galaxies and 100 billion stars in an average galaxy.

100 billion X 100 billion = 10000 billion billion = 10 billion trillion (!)

46

No way! I feel literally, ten billion times smaller than I did a few seconds ago. Is this right?

47

Congratulations. You have survived the Total Perspective Vortex.

48

Dennis Miller once said, "If I could talk to the animals… I wouldn’t 'cause they’re animals!

49

Little steps, Sparks.

50

Any intelligent species that developed a collective enterprise of scientific and technological progress would almost certainly, at some point, try to invent some means of high-speed long-distance communication – and would probably have to use the equivalents of telegraph and radio for the purpose. (So far as we understand physics, what else is there?) It would have to involve a device that converts electric/radio signals into something perceptible to their senses (which is exactly what we use). If they achieved radio in any form, there would be no practical obstacles to interplanetary communication.

51

Yes, I think so.

52

But what if they don’t feel the need to communicate? What if they’re part of some sort of hive mind? I can’t help but think of Lem’s Solaris, if you don’t know that book it’s about an intelligent ocean that communicates with human explorers by creating phantoms out of what it finds in their memories. Since the ocean is the only inhabitant of the planet, it has no need of radio signals. The humans aren’t even sure if it is intelligent because its intelligence is so strange to us. And I’m sure any real aliens would wind up being 100x weirder than that ocean.

53

If there are ten trillion of these civilizations, and there are 100 billion galaxies, then that averages out to 100 of them per galaxy.

And our galaxy is larger than average, so let’s say 200 here in the Milky Way. The diameter of the Milky Way is something like 100,000 light years, so the likely distance to the nearest one is, uh, seems like it ought to be somewhere around 5000 light years away. That’s a lot less than a million light years.

But ten trillion high-tech civilizations sounds too high. Even if it’s right, though, SETI isn’t coming close to thoroughly searching the nearest 5000 light years.

54

It seems like this is a big assumption. Maybe they communicate over long distances via quantum entanglement.

But I understand that we can’t detect a form of communication we aren’t aware of, so it’s the best we can do for now.

55

Is there a way, even hypothetically, to communicate via quantum entanglement?

56

But there would still be formidable obstacles to interstellar or intergalactic communication. As far as we can tell according to our best understanding of the sciences involved, any sort of detectable signal would need huge amounts of energy to travel more than a relatively short distance from its source planet. All those old radio shows from the '30’s and '40’s may still be traveling out there in space somewhere, but sooner or later (if it hasn’t happened already) the signal will become so weak that it simply won’t be distinguishable from background noise unless you’re positing some sort of incredible, super-scientific technology. And given that there is no certainty there will be anyone on the receiving end, there may not be much incentive or motive to devote massive resources to sending a recognizable signal across interstellar or intergalactic distances.

57

This is where I think we’re going wrong - f[sub]c[/sub] in the Drake Equation. Why develop technology? If you have a stable agrarian society where everyone has enough to eat and isn’t under threat from external invasion, what incentive is there to make “progress”? If you look at all the coincidences necessary for Western European society to become “scientific” (the Black Death being the most obvious), I think that the 1% chance (f[sub]c[/sub] = 0.01) in the standard equation is much too high.

58

IMO, the universe harbors:

  1. A great deal of life

  2. A moderate amount of intelligent life.

  3. A minimal amount of technologically advanced intelligent life forms that sent signals that we are scanning for at such a time in the past as to coincide with our intercepting them at this particular time on earth.

I believe most of the theories posited thus far in this thread that attempt to explain SETI’s silence are valid. I will add a couple more:

I believe that life is much more likely to germinate from and remain in a liquid environment. My guess is that the earth model of genesis in water (or at least mostly water) and progression to land is an exception to the rule. Planets devoid of liquid are not likely to harbor life. Planets that do contain life sustaining liquid most likely do not have non-submerged land masses or, if they do, probably don’t have habitable land masses to which the liquid born life forms may evolve onto. If this tenet is correct, the vast majority of intelligent live throughout the universe is submerged in some form of liquid.

Think of a society of mega-brained porpoise-people as exemplifying the typical intelligent life form in the universe. (For the sake of this discussion, let’s disregard the fact that porpoises, and other sea mammals, evolved from water-to-land-back-to-water). What sort of intra-species communications would they be likely to have evolved? Like our earth porpoises, they would most likely have developed communication signals that propagate in fluid. They may even have advanced sonar-type echolocation abilities. I believe that these types of signals would stay local and not propagate into space.

Let’s assume that our alien mega-brained porpoise-people developed opposable flipper fins enabling them to create technology. Would they still have any reason to develop signals that propagate into outer space? I don’t believe that they would. Technology that they create for their own enjoyment would still be fluid bound and local (no alien “Flipper” TV show signals would leak out toward us).

So, the only reason for the porpoise-people to develop signals that could be detected by us would be if they specifically wanted alien life forms to receive their signals. But, why would they? What’s in it for them? Inter- or even intra-galactic distances preclude the possibility of real-time two-way communication, so sending signals out is pretty much a one-way conversation and therefore non-productive on their end. Would they, like us, send signals and probes out simply for the “folly” of enlightening alien life forms? I tend to believe that most other intelligent beings in the universe would be more pragmatic than we are and shun endeavors that result in no direct payoff. Even if they did anticipate an alien return call for the benefit of future generations of their species, would they take the risk of provoking, say, a human-like visitation, where we bring along our long-lines and fishing trawlers only to bring them back to earth in Chicken-of-the-Sea cans? I think not.

Perhaps alien life-forms with far greater intelligence than we have could overcome the seemingly impenetrable barrier of galactic speed limits that preclude any sort of practical communication or travel between their planet and other intelligent-being bearing planets. But, I don’t think that super-intelligence is a universal norm. If alien life-form evolution is anything like earth life-form evolution, I don’t really believe that aliens will evolve intelligence far superior than what we humans have today. I say this because I don’t believe that we humans will evolve much greater intelligence than what we presently have. Technological advances will progress for a while (we will always need a better mouse pad), but shear intelligence for our species, I fear, is at or past its pinnacle.

Increased intelligence was clearly beneficial to the survival of our species for nearly all of its development. The brainy mutants would figure out how better to survive in their harsh environment and they would be more likely to attract mates and pass on their superior-brained DNA. At this point in time, however, I don’t see the evolution of greater intelligence as being of greater benefit to the survival of the individual in any practical way. In fact, analyzing present human breeding trends appears to bear out just the opposite. When my daughters are a bit older, I will be more concerned about the likelihood of their shacking up with the slow-witted jock than the pencil-necked egghead. I believe, with regard to the demographic of people with above-average-IQ’s up to and including mutant geniuses, physical attractiveness is inversely proportional to intelligence* – and the chicks always choose the hunks. If anything, I think the human race will experience a dumbing-down over time.

So, if most intelligent life forms are submerged in liquid and they are not fantastically more advanced than we are, these not terribly bright porpoise people will not be sending out any signals that we are likely to intercept.

*I am, of course, an aberrant example, being a meglobrainiac hunk. :smiley:

59

Take a hypothetically advanced Voyager-style probe. Give it engines, an electronic brain, a transmitter and the ability to self-replicate. Turn it loose, and one becomes four, four becomes eight, eight becomes sixteen, etc. How long to park one of these things around every star in the galaxy, broadcasting a simple hello? Assume they can get up to near c.

Millions years? Four million? Six? Eyeblinks.

Remember, once the first wave goes, it doesn’t matter what happens to your civilization. The probes will keep going, forever. Your species can evolve into a new form, go extinct, or whatever…but your message will still be out there. All it would take would be one civilization (just one!) in the entire galaxy to do this. You don’t need warp drive, or the spice melange, or Vulcans, or quantum entanglement. Just one civilization out of all those stars, with a mild interest and a technical ability a mere couple of centuries beyond our own, if that.

“What if they have a Prime Directive?”
99 out of a 100 civs out there could have a Prime Directive, but it only takes that one rogue civ to do this, and that one only had to do it once throughout its entire history.

“We can’t understand them, we’re too stupid.”
Possibly, but such a probe would be made for easy understanding, and likely be built by a civilization somewhere near our level of advancement.

“They didn’t think of it.”
Exponential growth is simple math.

“They nuked themselves in an inevitable orgy of self-destruction!”
They all did? All of them, all before they did this? Without exception?

“They hunted down the probes later on.”
Even if they scoured every system, they’d have to keep checking back to catch probes emerging from deep space…or leave probe hunters around to destroy incoming probes, etc., etc. The energy budget to stop the probes once they got started would be unfathomable.

“They aren’t here yet.”
Maybe, but there are almost certainly star systems out there that were stable and capable of bearing life when our planet was still a hot pile of rubble spinning around a new star. Systems and planets where they’ve had millions of years head start.

“They don’t need these they have [insert hypothetical FTL drive/comms here].”
Ahh, but they’d have sent the probes out before they figured out the wonder drive. Maybe not in all cases but remember, it just takes the one.

“They missed us.”
They missed a bright yellow star with rocky planets? More to the point, they missed all the stars in our local area? It’s possible, but not the most likely explanation I think, especially given the total absence of any other evidence of intelligent life out there.
Back to the probes. So it’s probably easy to do, all but impossible to stop, and so simple even this chimp-covered rock has got the idea before we can even do it. But we’ve heard nothing. In a sea with millions of islands, not one message in a bottle. Not once did someone try this, anywhere in our galaxy. Think about that. Not ever, since the origin of intelligent life in the Milky Way, did a technically adept species survive long enough to do some elementary math, glue a smart computer to a radio, strap engines and some sort of replicating hardware on it, then fire and forget.

Yeah, right.

The notion of hundreds or even just dozens of alien civilizations out there doesn’t jibe with this, and that’s at least one version of the Fermi Paradox, as I understand it. Works for me.

Answer to the OP: because there’s nothing to hear. Empty house, or at least a very quiet one, which is not a comforting thought.

60

[QUOTE=Grossbottom]
Take a hypothetically advanced Voyager-style probe. Give it engines, an electronic brain, a transmitter and the ability to self-replicate. Turn it loose, and one becomes four, four becomes eight, eight becomes sixteen, etc. How long to park one of these things around every star in the galaxy, broadcasting a simple hello? Assume they can get up to near c.

[QUOTE]

On this message board, we obey the laws of thermodynamics. I like to think that most moral alien civilizations use them at least as guidelines. You just slipped in an exemption request without anyone looking.

Where is the raw material for these “replicas” squared coming from? Where is there energy coming from out in interstellar space. The energy requirements for anything to even approach a significant fraction of C are so great that there is a good chance that nothing can overcome it.