Is SETI (Search for Extraterrestrial Life) a friutless approach?

[Andyvon]

Would anyone agree when I fear that SETI is barking up the wrong tree?

The search for other intelligences in the universe is limited exclusively to a radio search. I can't help feeling that modern astronomers are falling into the old trap of assuming that their science is very advanced, whereas radio technology is in fact young and basic. SETI is based on other intelligences also communicating in the radio spectrum so SETI astronomers must assume that other intelligences are just like!

There are people alive today who were born before Marconi sent his first radio message in 1901. If any alien observer had studied Earth at any time before then they would have found Earth to be radio dead. Yet Earth was teeming with life through the rise of plants, dinosaurs, the Roman Empire, the Victorian world with all it's advances in technology - but radio silent until 1901! It would have been wrong for those aliens to conclude that there could be no intelligent life on Earth - yet that is exactly the take of our astronomers today!

For that reason I think any other intelligence would probably be radio dead. All life forms would have developed in different directions so advanced forms similar to whales, apes and elephants on Earth wouldn't use radio. A more advanced intelligence would communicate with a technology far more advanced and we must have as much conception of their technology as the Greeks or Romans had of ours.

I just think that the modern SETI with radio telescopes is the wrong way to detect intelligent life on other worlds. That's why the radio astronomers keep reporting "No signals or replies yet!" I know there's no alternative - but radio is rather fruitless isn't it?

[Hopkirk]

If radio waves travel at the speed of light, and intelligent life forms are likely to be millions of light years away, then they will have to wait a long time to know we are here (or more likely , were here)

[jake-the-peg]

What do you suggest instead?

Radio transmissions are by far the longest distance communication method we know of. If we were close enough to examine the atmosphere of a possible planet spectroscopically we'd have other possibilitites.

But as it stands radio is our best chance. Yes a more advanced civilisation may have moved on to a more advanced technique but would still notice that in the same way that an ocean liner would notice smoke signals.

You also have to remember that SETI also looks for unsolicited signals, radio communications that are not in reply to anything we have sent

[Count-A-Strong]

I have to ask the same question as Jake. What other method of detection would you use? Pre radio waves, there's no detection method other than visual observation which at interstellar distances is impossible. I do agree however that what we are likely to detect is evidence of long gone civilisations.

[jake-the-peg]

Well count there are over 500 stars of a suitable type within 100 light years of us.

That's a small number compared to the total number but it rather depens on how common life is - cue discussion of the Drake equation

[naomi24]

No, I don't think it's fruitless. I don't think any method is fruitless. I firmly believe there is other life in the universe, including civilisations much older and much more advanced that our own.

Hopkirk, //If radio waves travel at the speed of light, and intelligent life forms are likely to be millions of light years away, then they will have to wait a long time to know we are here (or more likely , were here) //

That assumes the signals we are hoping to pick up are being sent now, but what if they were sent, say, 10,000 years ago - or 100,000 years ago - or a billion years ago?

[ludwig]

Yes, you can only communicate in the media you have available to you.
We may well be trapped inside a box shouting for help surrounded by deaf people who don't know we're in there, but what can you do?

[jake-the-peg]

Remember too that interception of a signal even from a long dead civilsation would still be one of the most important scientfic discoveries ever.

An electronic fossil of an alien life form

[Count-A-Strong]

>That assumes the signals we are hoping to pick up are being sent now, but what if they were sent, say, 10,000 years ago - or 100,000 years ago - or a billion years ago?<

As i already said Naomi, if we do intercept signals they may be from long gone civilisations.

Jake, isn't 500 clutching at straws in terms of the size of the universe. And wouldn't SETI have intercepted signals from these by now? (unless one of them is only just starting to transmit)

[Count-A-Strong]

I take your point Jake but wouldnt that be a bit of a non discovery? All it would prove is that the universe held other intelligent life at some point in it's vast history. I suppose you could conclude that if it once existed, it still could, elsewhere, but that's back to square one really.

[naomi24]

Yes, I know you said that Count, but who's to say they are long gone? They may well still be thriving. People often dismiss the idea that other civilisations could possibly have existed back in the far reaches of time, or that they possessed technical capabilities then that we, the inhabitants of a comparatively young planet, can at this moment in time, only dream of. If that's the case, then I can only wonder where their techology has taken them. It's a fascinating subject.

[naomi24]

Cross posted there Count..

[R1Geezer]

said it before I'll say it again, the whole idea is futile. Aliens exist we will never contact them, especially with the current knowledge of physics. Even if seti picked up an alien transmission, the aliens it came from would probably have been long extinct.

[naomi24]

Geezer, 'never' is a long time. :o)

[jake-the-peg]

A non-discovery? Goodness no!

We have only one example of life evolving - we don't know if it happens everywhere or whether it's incredibly rare.

The fact is that life started so quickly on Earth that we suspect that it happens whenever conditions are right.

It seems likely that out of 500 stars that are similar to our own you would have quite a few suitable planets although again we don't know for sure.

If we did find evidence of life close to us it would confirm that life starts very, very easily.

What further information you could derive from such a broadcast would depend on the nature of it, but it would significantly change the way we think about the Universe.

And the conspiracy theorists would have a field day pretending that the CIA made it up

[FraBrown]

Nail firmly on the head in the last sentence - What other alternative is there? Of course the system is not foolproof, but until there is a better way, why not stick with something which might well work?

[R1Geezer]

Hi Naomi, we don't have to repeat our discussion every time this comes up, I know your views, I actually hope you are right. But my knowledge of cosmology etc override that. Jake, the existance of alien life, possibly very rare but I think is statistically at least, certain.

[naomi24]

Geezer, unlike you, I don't claim to be an expert, but do you really think that your knowledge of cosmology overrides mine? In that case I wonder why, on more than one occasion, I have had to explain to you that the nearest star to our own is only around 4 light years away, and that there are at least 50 others, some of which are known to support planetary systems within 20 light years of the earth. Odd that. ;o)

[jake-the-peg]

Certain is a big word geezer

Especially when we've only this week confirmed the first Earth sized rocky exoplanet.

http://www.bbc.co.uk/...-environment-12158028

Your premise of statistics relies on the assumption that there is nothing special about the Earth.

With no other rocky examples we have no way to be certain that Earth isn't special in some way.

Of course I too think that is the case - but until we have another example of live evolving we don't know for sure - It could be that we are a trillion to one freak of nature

[R1Geezer]

when have you ever had to tell me that? I know all that, when I say it's 8 years to say hi, it's 4 years there + 4 years back!. I know about the close stars and the planets. It's precisely this knowledge that tells me that we will not communicate.

Ok ET is on alpha centauri, we know he's there we send a radio beam in that direction using the most powerful transmitter, by the time it reaches there is one photon per cubic mile, and that's the closest star! Even if ET pick it's up it's not going to me much of a conversation is it?