Why hasn't SETI found anything yet?

SETI has been searching for alien radio signals for years. Granted, aliens might be smart enough that they don't use radio signals.

SETI now has a program that looks for optical transmissions:

California astronomers are broadening the search for extraterrestrial intelligence (SETI) with a new experiment to look for powerful light pulses beamed our way from other star systems. Scientists from the University of California's Lick Observatory, the SETI Institute (Mountain View, California), UC Santa Cruz, and UC Berkeley are coupling the Lick Observatory's 40-inch Nickel Telescope with a new pulse-detection system capable of finding laser beacons from civilizations many light-years distant. Unlike other optical SETI searches, this new experiment is largely immune to false alarms that slow the reconnaissance of target stars.

SETI has people all over the world donating spare time on their computers to help hunt for alien signals:

Most of the SETI programs in existence today, including those at UC Berkeley build large computers that analyze that data from the telescope in real time. None of these computers look very deeply at the data for weak signals nor do they look for a large class of signal types (which we'll discuss further on...) The reason for this is because they are limited by the amount of computer power available for data analysis. To tease out the weakest signals, a great amount of computer power is necessary. It would take a monstrous supercomputer to get the job done. SETI programs could never afford to build or buy that computing power. There is a trade-off that they can make. Rather than a huge computer to do the job, they could use a smaller computer but just take longer to do it. But then there would be lots of data piling up. What if they used LOTS of small computers, all working simultaneously on different parts of the analysis? Where can the SETI team possibly find thousands of computers they'd need to analyze the data continuously streaming from Arecibo?

seticlassic.ssl.berkeley.edu...

SETI has a telescope array:

The ATA will consist of approximately 350 6.1-meter offset Gregorian dishes arrayed at the Hat Creek Radio Observatory site. Given the number of antennas and large size of the primary beam (approximately 2.5 degrees at 21 cm wavelength), this array will have an unprecedented amount of flexibility in observing. Several individual users may simultaneously use the array to observe a different part of the sky at an independent frequency, or image the sky at one or more frequencies.

They talk about whether or not to send a message in reply if we detect signals:

Until now, SETI researchers have not been very interested in broadcasting. The reasons for this are several. To begin with, we are a technologically young civilization. We have had radio for a hundred years or so, but there are surely societies that have possessed the ability to send high-powered signals for tens of thousands, if not millions, of years. Consequently, since we are the new kids on the technology block, it may behoove us to listen first. Some have also expressed concern that broadcasting might be dangerous, literally calling attention to our existence. However, the evidence of technologically sophisticated life on Earth is already on its way into space, and there is no bringing back these transmissions.

They talk about the social effects of a detection:

Sociological studies suggest that announcement of a signal would lead to confusion and excitement, with a desire by individuals to "know more", but little panic or hysteria. While some religious groups are expected to reject the idea that we are not alone, most would not, and some would embrace the discovery as reinforcing their own beliefs.

They talk about procedures to follow if they find something:

Any individual, public or private research institution, or governmental agency that believes it has detected a signal from or other evidence of extraterrestrial intelligence (the discoverer) should seek to verify that the most plausible explanation for the evidence is the existence of extraterrestrial intelligence rather than some other natural phenomenon or anthropogenic phenomenon before making any public announcement. If the evidence cannot be confirmed as indicating the existence of extraterrestrial intelligence, the discoverer may disseminate the information as appropriate to the discovery of any unknown phenomenon.

In fact they've got all kinds of incredible info on their web site:

www.seti.org...

But despite all their years of searching, they haven't found anything yet. Are they looking for the wrong thing? Are we not thinking 'alien' enough to figure out what kinds of signals we should be looking for? Are we alone in this big universe but just don't know it yet?

Why hasn't SETI found anything yet?

Is it possible that maybe there is just nothing else out there? I know, probably not a bright response on this site but in exploring options, this could be one. Or if I want to stay in line with the believers, perhaps our technology is just no where advanced enough to pick up whatever type of signal aliens generate.

Also keep in mind that SETI has only been able to scan less that 1% of the sky with current technology.

Imagine if they were able to scan every known star system in the universe, if they did not find anything then that would be truly amazing. But of course there is other life in the universe you would have to be a butt head to think otherwise.

Originally posted by pompano
Also keep in mind that SETI has only been able to scan less that 1% of the sky with current technology.

Imagine if they were able to scan every known star system in the universe, if they did not find anything then that would be truly amazing. But of course there is other life in the universe you would have to be a butt head to think otherwise.

Opinions are just that, opinions, not facts. To accuse someone of being a "butthead" just because they have doubts as to whether aliens exist is somewhat rude and immature and just not necessary. Yes there may be some type of plant/animal life yet to be found but to jump to aliens flying to earth to visit is still a bit much for me to swallow yet. But as I previously said, my mind is not closed, it just still needs some convincing. Have a nice day.

Why? Simply put... because it is very unlikely that alien intelligences/technologies will be listening to OUR radios, and furthemore, if they get the signal, they still need to put it back into somthing that makes sense for them...

IMHO very unlikely scenario, though I'm running SETI@Home on my puter for more than 2 years now...

Well, as I understand, Frank Drake is the head of SETI and also the father of the famous theory about X number of planets containing life, etc, etc as mentioned by Jodie Foster in the movie "Contact". Here's a 2004 Wired article from him about the Drake Equation. I had not heard the 1% figure before but that sounds about right. SETI will take a long time.

Actually, I think the larger question is this: Since we can agree that Earth is full of resources and is basically a gleaming jewel floating in space, how likely is it that ET has not sought us out and found us already? I say that's more likely since Earth has been here for at least 4 billion years.

I would imagine that a planet with a native, easily hypnotizable population would be a resource even greater than gold or 'unobtainium' or whatever other resource a species might desire. Slavery was outlawed on Earth not due to moral reasons but mainly because it didn't make financial sense after the industrial age. Slavery works, however, if you are A: way advanced from those you enslave, B: guide their evolution, and C: know how to hide well.

I'm not saying they're here already, but I think planets like Earth would be sought out by those alien civilizations. I mean, if you were flying around in space, observing gas giants and barren planets like Mars, wouldn't you see Earth as a hugely more valuable resource? Assuming ET isn't interested in us or hasn't found us yet is like assuming that an unlocked Corvette with the keys in it in would remain unstolen. In 4 billion years, it is illogical to assume aliens have never visited Earth, IMO.


[edit on 12-6-2005 by smallpeeps]

I've pondered this thought a few times and I always wondered about radio signals.
The problem with this civilisation, is that we're built to be egotistical!
I mean, we assume that because no one answers, there's nobody there or we haven't reached them yet.
Scientists agree that the laws of physics on this planet may not apply elsewhere, so therefore the ways of communication on this planet may not apply elsewhere.
Maybe, they're 'screaming' at us right now but we can't hear them, maybe the idea of contacting other species across the void has come and gone and we've just missed out by a couple of light years.
Maybe we're alone.
I think that if SETI do find something, then it won't matter if, (supposing there are powers-that be) a higher control decide to stifle it, because that a civilisation that wishes to make contact, will deliver a message that all mankind will be able to 'hear'.
If a contact comes to pass, it will be interesting to see centuries-old religeons and control systems shuffle and adjust to imply that THEY were right!

What we actually know about other planets (beyond our Solar System) is really almost nothing. The Earth may be special, but it seems to me the odds are more in favor of us not being unique at all.

Radio waves and the other means SETI uses have physical limits, the speed at which radio spreads is slow on a galactic, let alone a universal, scale. In the infinity of Space the percentage of what they have done is so close to zero that you might just say zero+. I fully support their efforts, and they are doing the best they can but it means nothing in terms of answering the question in the negative. They have not disproven anything and never, ever, will. But they might find someone, that one race that happens to use the right form of energy and has been doing it for a very long time.

Anyone know how long it would take radio waves to reach the Star that is closest to Earth? I do not off the top of my head but it would be a useful fact in this discussion.

Memorialday1999,

If you accept life, and the huge nature of the Universe as we currently know it (with full knowledge that size will be forever expanding, imagine how many Galaxies we will know about in a 100 years, or 1,000.) then intelligent life naturally follows. If there is any intelligent life in the Universe, again given the size and potential number of Planets, then we must be talking about a lot of different races with intelligence.

Last step. Technological advancement is a unique thing, 1 person changes the path for the whole planet and all of science. So each Race would have to have a totally unique path of development, even assuming everyone is operating under the same rules. This gives us people much 'younger' than humans, and some who are much 'older'. And since at the very least the older races could have been around millions of years how can we assume anything would be beyond them?

Today we send robots to other planets, would not some of these Races send things to ours? I think that there are multiple explainations for a number of types of events, but on the simple level a robotic-style probe has to be the tool for choice for anyone with the ability to create them.

A.T
(-)

Originally posted by Memorialday1999

Originally posted by pompano
Also keep in mind that SETI has only been able to scan less that 1% of the sky with current technology.

Imagine if they were able to scan every known star system in the universe, if they did not find anything then that would be truly amazing. But of course there is other life in the universe you would have to be a butt head to think otherwise.

Opinions are just that, opinions, not facts. To accuse someone of being a "butthead" just because they have doubts as to whether aliens exist is somewhat rude and immature and just not necessary. Yes there may be some type of plant/animal life yet to be found but to jump to aliens flying to earth to visit is still a bit much for me to swallow yet. But as I previously said, my mind is not closed, it just still needs some convincing. Have a nice day.

Wow, couple of things here. First off animals and plants are living how do you know (what we would call animals) on other planets have not evolved enough to invent radio.

Secondly, and this is the one that really makes me laugh is the fact that this thread had nothing to do with "aliens flying to earth to visit". What it did have to do with was why has SETI not found anything yet. To that I replied that they have scanned less than 1% of the sky and you could come up with no intelligent response.

It seems to me that you really are hung up on this "aliens flying to earth to visit" thing. Hope it's not eating away at you. And please if you did, do not take the butthead thing personlly I was not reffering to you specifically.

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I read an interesting article some months back. Please don't ask me to provide a link or a magazine.... At my age I'm lucky to remember that I have a name, on occasion...

At any rate the basic of the article was about how our technology is going more and more digital. And as we go more digital, we are emitting less and less tv and radio programs into space.

Now... If, and I'm saying this as a big "IF", there are other civilizations and they are anywhere from 50 to 1,000,000 years ahead of us, then I imagine that the possibility exists that they are not emitting any radio waves that we can detect. Put that on top of the fact that we have only hit about 1% of the stars (to take into consideration that some civilizations could be on a par or even behind us), and we could be a very, very long time catching any kind of indication that there is civilization out there.

And, as much as I hate to bring it up like this, but, frankly, it seems as if the now famous Drake Equation is, more or less, an exercise in what-if...
It's a nice thing to look at, and it looks reasonable, but, no matter what you may say about it, it's simply a "surmise", a rationalization for what could be.

Still waiting to see where it all goes.

Just so you don't thik that I am trying to throw cold water on anything ... I remain eternally hopeful that we will find someone else out there and they won't be hostile.

[edit on 12-6-2005 by sigung86]

Anyone know how long it would take radio waves to reach the Star that is closest to Earth? I do not off the top of my head but it would be a useful fact in this discussion.

Radio waves travel at the speed of light (186,000 mps). There for we could reach the nearest star system to us with radio waves in 4.36 years. However it will take 7,200 years to reach the furthest star system yet identified. Hope this helps.

nearest star system 4.36 light years from Earth
www.space.com...

furthest star 7200 light years away
www.science.psu.edu...

A.T. I think you made a good point.

It is true that when looking into space, the further we look the farther back in time we see.

If you were looking at Earth from 1000 LY's away , you would not detect radio signals propagating from Earth , because 1000 years ago we were not using them.

That would also be true of SETI's search .

[edit on 12-6-2005 by lost_shaman]

Originally posted by SpookyVince
Why? Simply put... because it is very unlikely that alien intelligences/technologies will be listening to OUR radios, and furthemore, if they get the signal, they still need to put it back into somthing that makes sense for them...

IMHO very unlikely scenario, though I'm running SETI@Home on my puter for more than 2 years now...

Yes, possibly the ETs are far advanced than us that they don't use radio, or they just have a different way of communicating.

Well what makes us think alien use our signals? Highly unlikely. But they might not want to send back signals. Maybe the UFOs we've seen are them responding to our signals. Maybe these UFOs don't have "humanoid beings" on board. Maybe instead they send android type creatures to check us out...?

Maybe the reason why we've had so many recent reports of UFOs is because the aliens HAVE picked up our signals?

Just because we haven't heard from them doesn't mean they haven't heard from us.

AWingAndASigh maybe correct, life from elsewhere may have listened to our recent (because of time delay etc) signals and realised that we're not only neurotic and lack trust, but we're a warring creature and that we must be approached with caution.
Damn... if only the New World Order had thought about this!
I mean, we see things in the sky and 'squabble' about whether it's something from an old book about religeon or whether it's an object that transports humanoid creatures to our planet that may only peer at us like folk at a zoo!
When we eventually realise that sex, video-enlightened music and the lust for so called 'precious metals' are merely distractions from the reality of helping our fellow man, then... and only then we can toss our hat onto the civilised planets talble.

I wonder... sex, bright lights and sounds and also to covet possesions are also distractions of our other occupiers of this planet. Mmmm...

I agree with most of the others,

Aliens probably wont use Radio siginals, that's probably too inferior for them. Maybe fiber optic siginals. Also, a good point to make as to why they wouldn't use radio siginals, is that, if you ever remember heat waves, or when there is a lot of energy comming off the sun, what's the first thing that dies? Our cellphones and radio stations. And seeing as the aliens need to communicate from one side of the universe to another, that seems very much a con, also the radio siginals are too slow, pointed our earlier.

I'm a skeptic, but I would assume they would use light to transfer data. Or as many people believe, they're telepathic, who needs a radio?

I'm a skeptic, but I would assume they would use light to transfer data. Or as many people believe, they're telepathic, who needs a radio?

I've been wondering what that alien voice in my head was!

I would imagine telepathy has distance limits, too. Otherwise, aliens might show up here with a major migrane headache - pass the tylenol. Or perhaps the sour milk, as in Alien Nation.

Telepathy probably does have limits, so... Let's just assume they have something like a "telepathy" station around the galaxies or so. Maybe that's why some of them just stop by and "crash" into earth? They're setting up radio stations!

That would be pretty cool, Having a telepathy station, which plays music and you could control it mentally and such

But, what doesn't have limits?