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World & Current Events > Seth Shostak and SETI

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message 1: by Ian (new)

Ian Miller | 11762 comments This follows from Scout's request. At the recent astrobiology conference in Rotorua, Seth Shostak gave presentation on why the search for ET by listening with radio telescopes so far has failed to find anything. What he said showed that it was going to be a really difficult problem, and at the end, I raised an issue that is actually a quote from my "A Face on Cydonia", where the issue of listening for ET was part of the plot. The reason you don't hear anything is because everyone out there is listening and nobody is transmitting.

Why would nobody be transmitting? First, suppose you wanted to send a coherent signal to Earth. Seth stated that from about 50 light years away (I hope I have that distance right - it was not important at the time) all you need to do is send a focused signal with about 300 MW strength. Um, that costs a lot, and because it is aimed specifically at a planet, you have to be fairly certain there is a potential civilisation. Even if you know there was life on Earth, and even if you know there were land plants, it has taken several hundred million years before we have capable of even listening. Then there is the question of what frequency do we listen? So it seems obvious to me that nobody is going to devote 300 MW of power to one planet for a hundred million years, say. On top of that, we have the problem that if you do send a message from 50 light years away, it is impossible to get a response inside a hundred years, so do you send a message when you will be dead when an answer comes?

Apparently SETI is now going to focus on red dwarf stars, because they are more common. If my theory of planetary formation is correct, that is like looking for your car keys under the lamp post because the light is better there. The problem is that the better prospects, mature G stars, are somewhat rarer and tend to be well-spaced out.

So my view is, SETI is doomed to fail. The problem, though, is I can't know that, so they will keep trying. Any thoughts?

message 2: by Leonie (new)

Leonie (leonierogers) | 1579 comments I think you make some great points, Ian. I find the idea of life in other places fascinating.

Having said that - what kind of life? Will there be life forms so different from our own that we might not recognise them as life?

And of course, given the distances involved, could we end up hearing from civilisations that are now extinct?

message 3: by Michel (last edited Jul 13, 2018 08:22AM) (new)

Michel Poulin Extinction of civilisations after a few millenias of existence is another problem in this equation. What if there was a highly intelligent alien civilization in a solar system within 50 light years, but millions of years ago? What are the chances that two intelligent civilizations would develop and exist within 50 light years and at the same time? The answer is: 'very unlikely'. So, it is as much a problem of timing than it is a problem of distance. I strongly believe that there are other intelligent civilizations around us in this galaxy, but I also believe that the chances of getting into contact with one of them is highly unlikely. By the way, can we really call ourselves 'an intelligent civilization', with our propensity for war and reckless pollution of our planet? An alien observer would probably say 'no!' to that.

message 4: by Ian (new)

Ian Miller | 11762 comments The question of whether civilizations last is an unknown. Maybe civilizations can sort out this tendency to self-destruct - we are too young to know. However, the question of life is not quite so restricted as the question of intelligent life.

Leonie, my presentation stated that life would almost certainly be like ours at the fundamental level. The reason lies in reproduction. While it is dangerous to say that what we can't think of doesn't exist, the requirements to reproduce AND the requirement that it can evolve naturally virtually require RNA to be the starting point. I shall explain why in the blogs at a later time.

message 5: by Ian (new)

Ian Miller | 11762 comments Leonie, regarding the question about "dead civilisations" a message from about 50 light years away, with the signal aimed at us and focused (but not using a laser) would, from memory, take about 300 MW power, so the chances of hearing something from long extinct civilisations is not great. One problem is that space is not entirely empty, and dust, etc, scatters light, and there is also the problem that the signal spreads out and gets weaker. There are stars a few light years away that you cannot see with the naked eye because they are too dim, and even a dim star has far more power that any signal; (but of course it is not focused).

message 6: by Scout (new)

Scout (goodreadscomscout) | 6151 comments Considering the costs, distances, and time involved, goals would have to be long-term, way beyond our lifetimes and with little hope of a response. I hear you guys saying it's just not going to happen. And if it did, things might not turn out so great for us. That has to be a consideration, doesn't it? Might be best to stay under the radar and spend our money on concerns closer to home?

message 7: by Ian (new)

Ian Miller | 11762 comments There is the possibility of an accidental signal. In my novel where this came up, there was a brief signal that was impossible to decipher. What it was (according to the plot) was a signal from an alien base to one of their ships or bases. The thing about messages is they do not stop just because someone receives it as the signal is to broad. So messages might come that are not intended for us at all.

message 8: by Nik (new)

Nik Krasno | 16030 comments SETI is already quite successful in that it attracts and consummates a substantial funding -:)

message 9: by Ian (new)

Ian Miller | 11762 comments True. They have a formidable array of electronics too. If the objective was to spend money and build complex electronics, they are hugely successful :-) Oddly enough, once upon a time they did get one brief signal, but nobody knows what it meant. If it were a communication between two aliens and picked up accidentally, it would not be repeated.

message 10: by Scout (new)

Scout (goodreadscomscout) | 6151 comments Nik wrote: "SETI is already quite successful in that it attracts and consummates a substantial funding -:)"

Good point, Nik :-) The money could be better spent closer to home. But what would those scientists do for a living then? Everything I've read here says that they should be unemployed.

message 11: by Ian (new)

Ian Miller | 11762 comments Heavens no, Scout. But they could be employed on something more profitable.

message 12: by Scout (new)

Scout (goodreadscomscout) | 6151 comments Such as?

message 13: by Ian (new)

Ian Miller | 11762 comments Scout - our modern society is almost totally dependent on technology, but developing it is far from over. There should be something constructive they could do. Look at it this way - through my life I have not found "useful things to do" to be in short supply.

message 14: by Scout (new)

Scout (goodreadscomscout) | 6151 comments When I said "unemployed" I meant in the context of SETI, which seems to be wasting money. But I totally agree that those guys will be otherwise employable and use those big brains I wish I had.

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