Possible reason we've made no contact with ET

[bdewoody]

Think about this. Assuming there is a way to travel between the stars where a round trip would take only 5 to 10 years for the travellers, would they want to do it realizing that upon returning home everyone they knew would be long dead. So the only form of interstellar travel will most likely be those trying to find a new home and not planning to return to their point of origin. For us as well as other intelligent species space travel on a day to day basis will most likely be limited to the area around their own star. Realizing this why bother looking for someone you can have no meaningful contact with. Just imagine sending messages you will have to wait possibly hundreds of years till the answer comes. It might be different if we lived in a star system that had several close neighbors only one or two light years away.

I wish as much as anyone that star travel such as depicted on many sci-fi series was a practical possibility but in all likelyhood no matter how many other inhabited planets there are around other stars we will never interact with any of them.

Even so there is a lot of interesting stuff within our reach and I hope that the people of this planet will be bold enough to develope a means to visit these places.

[SkylarkDuQuesne]

Realizing this why bother looking for someone you can have no meaningful contact with. Just imagine sending messages you will have to wait possibly hundreds of years till the answer comes.

I, personally, believe the reason to search for extraterrestrial intelligence is to answer the question "Are We Alone?"
The people working on the search realize we are just taking the first 'baby steps' in our quest, and may not live to see any results. That's fine by me, someone has to start somewhere.

[bdewoody]

I have no problem with the SETI program. As a matter of fact I have been a participant in the SETIathome project for over ten years and have contributed a sizeable number of cpu hours to analyzing scan data. I also believe there is an outside chance we may detect some evidence of ET. But unless what is currently believed to be true about relativity is not the final word on the subject I honestly believe we will never share any meaningful dialog with any ET's.

[Antwerpo]

If I look at all life on earth I only can notice that we even don't make contact to our closest neighbors (animals). This inability to interact with other species should make it clear why we were never contacted by ET. I really wonder why people want to interact with ET because ET won't be human and won't be speaking our language. It's even weirder that people think ET would have evolved like we and would be looking for us. The chance of life being spread over the universe is gigantic, but the chance of life in the universe evolving the way we do seems very low. Even on a planet that is crowded with life no species ever evolved like we did.

[dragon04]

The most likely reason, assuming that ET DOES exist is that, well, they haven't heard us yet. We see these documentaries all the time discussing how I Love Lucy is 50 light years out and such, but in all reality, nobody's decoding the weak signal that can't be heard above the cosmic background noise and all the noise sources in and around their stellar neighborhoods as well.

Catching a view of Hitler opening the 1936 Olympics isn't finding a needle in a haystack, it's finding a needle in a hay field.

Really, the only method by which ET might hear us is through the use of a very powerful, relatively tight beam transmission. Not the low power omnidirectional stuff that we've pumped out over the last several decades.

Then, there's another problem. Even with a powerful transmitter using the tightest beam possible, we have to "hit" a target that's actually listening for someone. Not only that, but we have to hit it not where it is now, but where it will be in the future. If we shoot a fibonacci sequence at Alpha Centauri and don't take its proper motion into account, our signal will miss it by minutes, hours, days, weeks, months, or even years. Imagine trying to accurately put a signal onto a planet (that we don't even know to exist) in the A Cenaturi system.

First of all, we have to get the signal to hit the system in 4.3 years from when we transmit. Then, depending on how narrow the beam is, strike a planet (if one even exists) at just the exact time its orbit intersects our beam and then, it has to be a repeated signal that repeats often enough to be recognized as intelligent and extra terrestrial.

As we transmit out to greater distances, the likelihood of a "hit" decreases on order of magnitude. I think that if or when two intelligent civilizations interact, first contact was probably pure serendipity barring some technology that we are unaware of at this time.

Obviously, the same thing applies to us receiving a CQ from Echo Tango. They're putting a message in a bottle and hoping that it ends up on a beach on the other side of the Cosmic Ocean. It would be far more remarkable if we ever do find that bottle than not even if there are hundreds of senders out there.

[Antwerpo]

Do all other planets have the same resources we have to be able to make such signals? I mean isn't it possible we just lack a resource that enables us to reach that technology the supposed ET used to make broadcasts or signals? I'm just imagining a planet where the atmosphere limits the range of over the air broadcast, they would surely look at other technology to send a signal from ET 1 to ET 2. It's weird to think that an alien civilization would evolve just like us with the same technology path. Maybe they use telepathy and never felt the need to be busy with sending signals.

I'm very sure there is alien life out there, but I really don't think they evolved like we did. What we call intelligence is rare on a place that is filled with life so the odds of it being common throughout the universe is almost nihil. So even if 1 or 2 such civilizations would exist in the same timeframe the universe is too big for such civilizations to detect each other.

[thebigcat]

The most likely reason, assuming that ET DOES exist is that, well, they haven't heard us yet. We see these documentaries all the time discussing how I Love Lucy is 50 light years out and such, but in all reality, nobody's decoding the weak signal that can't be heard above the cosmic background noise and all the noise sources in and around their stellar neighborhoods as well.

Let's keep in mind that the Drake Equation was originally formulated to calculate our chances, roughly, of receiving the normal everyday RF transmissions of alien civilizations, ET's I Love Lucy as it were. It was a guess at how many alien civilizations we might discover just by listening with our radiotelescopes. The equation, N = R*x f(sub p) x n(sub e) x f(sub l) x f(sub i) x f(sub c) x (1 + n(sub r) ) x f(sub m) x L, turns out to be missing something. Let's call it C(sub s), the chance of signals surviving the interstellar distances and being distinguishable above the cosmic background noise. The real equation should thus be:

N = R*x f(sub p) x n(sub e) x f(sub l) x f(sub i) x f(sub c) x (1 + n(sub r) ) x f(sub m) x L x C(sub s)

And since C(sub s) is zero, or practically as near to it as makes no difference it renders all the other numbers in the equations meaningless. You can plug whatever you like into them and N is still going to end up as zero. Which in reality it has.

[ZenGalacticore]

There's been much talk lately about the cosmic background noise rendering any radio transmissions from Earth as drowned out and unreceivable. But I've also read that because of all of our radio and tv transmissions, relay sats etc, that the Earth is actually a larger radio source than the Sun.

Any advanced aliens that bothered to zero in on our system and lend an ear, would surmise that something unusual was going on on the third planet, even if they couldn't totally filter out all the noise or differentiate or hear a particular transmission. And if they were only say 40 lys away and roughly 1,000 years ahead of us, they may well be able to filter out at least a portion of the noise and also come to the conclusion that something unusal was happening here.

What are the odds of a technical civ within a 40 ly radius? Darned if I know. We don't really know the odds. Yet. I would err on the side of conservative and guess that the nearest tech civ is 200 lys away. But again, we don't know. It could be 2,000 light-years, or 20,000.

[rocketmonkey]

Well, it is amazing humans survived at all because of lions and other predators. So what if aliens are just... animals? With no way to communicate with us?

[thebigcat]

There's been much talk lately about the cosmic background noise rendering any radio transmissions from Earth as drowned out and unreceivable. But I've also read that because of all of our radio and tv transmissions, relay sats etc, that the Earth is actually a larger radio source than the Sun.

Any advanced aliens that bothered to zero in on our system and lend an ear, would surmise that something unusual was going on on the third planet, even if they couldn't totally filter out all the noise or differentiate or hear a particular transmission. And if they were only say 40 lys away and roughly 1,000 years ahead of us, they may well be able to filter out at least a portion of the noise and also come to the conclusion that something unusal was happening here.

What are the odds of a technical civ within a 40 ly radius? Darned if I know. We don't really know the odds. Yet. I would err on the side of conservative and guess that the nearest tech civ is 200 lys away. But again, we don't know. It could be 2,000 light-years, or 20,000.

I have been maintaining for some time that any aliens that advanced and that close by would have a sufficiently developed visual search capability and would know from the same methods which we are now using to locate extrasolar planets that the third planet from this star is ripe for supporting life. If there is a sufficiently advanced civ within 40 ly (your choice of a disdance), and that's a fair sized volume of space, who, being limited to their home system by speed of light travel, wished to send a message across the void in the form of a focused beam of radio energy which would intercept our world they would do so. Which is not to say that we would have heard it already, or that they would have sent it already. Sagan's silly dream of fireflies blinking in the cosmos is just that, a silly dream, and the "WOW" signal a poor hoax. They weren't listening on the hydrogen line because Sagan said the aliens might understand the significance of that frequency and broadcast on it, they were listening on it because it's conveniently a band width which we don't use by agreement and people would think it really was aliens if they heard something on it and they could make it look convincing. They learned a trick from Charles Dawson, the guy behind the Piltdown Man hoax, in that they gave the scientific community exactly what they were looking for. But I digress...

Someone out there could be watching our planet, reading the spectroscopic analysis, could have been doing it for quite some time. Could have been doing this with every other suitable planet in the area. And notice the changes in our atmosphere, the increased hydrocarbon emissions, and come to the conclusion that there is intelligent life which is going through a process of industrialization. Our hearing from these people, if they do decide to send a message, is entirely dependent upon their agenda, not ours.

[ZenGalacticore]

I have been maintaining for some time that any aliens that advanced and that close by would have a sufficiently developed visual search capability and would know from the same methods which we are now using to locate extrasolar planets that the third planet from this star is ripe for supporting life.

I didn't know that you have maintained that, but I'm glad you have. Please read "Alien Telescopes, Remote Sensors, and Billion Year-Old Civs" in this Forum.

If there is a sufficiently advanced civ within 40 ly (your choice of a disdance), and that's a fair sized volume of space, who, being limited to their home system by speed of light travel, wished to send a message across the void in the form of a focused beam of radio energy which would intercept our world they would do so. Which is not to say that we would have heard it already, or that they would have sent it already.

I agree. But my 40 ly radius was an "if", and quite arbitrary. As I implied, it could be 40, or 40,000 light-years distant to the nearest broadcasting, technical civ. We have no idea how close the nearest one is, as yet.

Someone out there could be watching our planet, reading the spectroscopic analysis, could have been doing it for quite some time. Could have been doing this with every other suitable planet in the area. And notice the changes in our atmosphere, the increased hydrocarbon emissions, and come to the conclusion that there is intelligent life which is going through a process of industrialization. Our hearing from these people, if they do decide to send a message, is entirely dependent upon their agenda, not ours.

Again, I agree. Please read my thread "Alien Telescopes..." in this Forum if you haven't already. It's still on page one on the index page. I'm sure you'll like it as we are like-minded on this idea. Then we can discuss this further and know each others view on the matter.

[dragon04]

There's been much talk lately about the cosmic background noise rendering any radio transmissions from Earth as drowned out and unreceivable. But I've also read that because of all of our radio and tv transmissions, relay sats etc, that the Earth is actually a larger radio source than the Sun.

You have to take that with a grain of salt. Even if Earth is a brighter radio source than the Sun, that's like saying that an Atom is more visible to the naked eye than a subatomic particle.

EDIT: If an ET civilization DID detect a signal from Earth, its likely source would be from our military radars that send out powerful pulses looking for target return.

[thebigcat]

I have been reading that thread, ZG, but I saw no reason to post on the subject while the discussion was active.