Why is there SETI?

You have just assumed that every ETI would use radio technology which is a good assumption, but you have assumed that ETI would go on using radio technology for the rest of it's existence also as a means to try to communicate to other civilisations. Using Dinosaurs great illustration of the time scale of the universe, we have had radio technology for "2 seconds". Will we still use it in 10 minutes?

Also you are really stretching your argument as thin as it can go when saying we may be the only ETI in the universe. Astronomers estimated 70 billion trillion stars in the visible universe alone. Don't think I need say more.

I grant you credability by saying we could possibly be rare in the galaxy purely because given our few decades with technology we have found nothing, but I call the men in white coats to anyone who say's we are the most intelligent beings in the universe full stop.

 

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Maybe, just maybe the odds of finding ETI are 70 billion trillion to one. No one knows for sure. It's possible that some or most civilizations out there in deep space don't make to the full 2 seconds let alone 10 minutes on the so-called Dinosaur's time scale because of their either own stupidity for creating wars, natural disasters or global exinction events like asteroid impacts, supervolcano eruptions, and/or their own sun turning into a Nova, Supernova, Red Giant & etc., etc.,). In terms of most intelligence beings in the universe being here on the planet earth? What standard of intelligence are you using for comparism? Monkeys or Neanderthals?

Okeydoke

 

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Replying to your comment about us possibly being alone in the universe, that would mean us as human beings would be the most advanced species in the whole shebang alive today. Which is a concept I find more astounding than the existence of ETI.

 

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I think the most advanced species live in the ocean. The Dolphins or Whales are probably the most advanced species. Humans haven't figured it out yet. The Dolphins and Whales have.

Okeydoke

 

The only thing we lack right now is the will. We should have colonies in several places already. We should have a generation ship on its way. If a country can waste so much of its resources on three stupid wars in a row, make it four during the atomic age, we have the resources to do these things.

 

Possibly... perhaps they could paint a mona lisa if they had arms and thumbs instead of larking around having a laugh

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Well, I think you do need to say more if you feel that is a convincing argument.
First, lets eliminate all the stars that are more massive than 1.5 times the mass of the sun. They wont stay on the main sequence long enough.
Eliminate all the stars older than say ten billion years - metallicity too low.
Eliminate all stars in multiple star systems (that's about 75% plus), because of orbital instability.
Eliminate all the stars that have mobile gas giants that migrate inwards. At present that is the majority of stars with planetary systems, though I accept that may be an artifact of the current detection methods.
Eliminate stars in the inner third of galaxies. The stellar density is so great nearby supernova are much more likely.
Eliminate stars that regularily spend time in the spiral arms. Same argument as above.
The list goes on. And I haven't even started in on planetary characteristics yet.
Intelligent life may be common, but based on what we know today it may be unique to the Earth.

 

I don't think Dolphins or Whales 'have' to paint a 'Mona Lisa' to be happy. Instead, they have probably evolved to higher level of intelligence, where perhaps they are just happy to be alive and enjoy the beauty of their own environment and each other enough to where they feel it's just fine the way it is. No need to make any changes. Humans on the other hand......???

Okeydoke

 

Use the link I provided to get an idea of detection ranges. If you google the net, you can rapidly get an idea of what types of signal strengths we here on earth are using for various purposes. My impression is that most of them would not be detectable by SETI from even one light years distance. A 1 Ghz, 15m^2 transmitter blasting out at 40,000,000 watts can be seen at 62 light years.

We don't use 40,000,000 watt transmitters...

But these are of no interest to us. While such catastrophies might be the norm, they cannot be an absolute rule. If ETI is common, then some proportion of these civilizations survive indefinitely.

No, we can only eliminate those systems where the migrating gas giants preturb the entire spectrum of the star's habitable zone, have no moons, nor capture moons, capable of developing life. Given the vibrant nature of Jupiter and Saturn's constellations, this would be an outrageous assumption on our part.

No, we can only eliminate them as candidates while they are part of a multiple start system. Also, I doubt all binary systems can be eliminated as candidates.

We're going to be around for quite some time so 300 years is a drop in the bucket. If our hubris prevents the understanding that this issue is one of thousands (or millions) of years, then the discussion isn't really going to lead anywhere. The only possibility that this issue will develop immediate consequences is if ET is already here. (Of course he's not. Those hillbillies just happened to guess that a flying saucer is, according to the Lockheed Skunkworks, the ultimate shape for defeating radar...)

There is no "worthwhile" analysis to be had, only guesses where people assign value to theories via the science feel of his/her demeanor and their ability to dazzle us with fancy lexicon.

It is certain that the emergence intelligent life conforms to some model of statistical probability. Generally, I'd guess that the longer a planet maintains complex life forms, the more likely it becomes that it will generate an intelligent species. Given a long enough gestation period, I'd suggest that the odds of intelligence approach certainty. The question therefore is whether or not a statistically significant number of planets are around long enough for trinity to occur. Assuming Earth to be average, then the answer is obviously, "yes".

Afterall, if Mars was a bit bigger it could have probably had more significant life around today (although it looks likely life exists on Mars anyway). Imagine that, two neighboring planets with life...

We came fairly close to having not one, but two earths in this solar system. It seems counterintuitive at best (or dogmatic at worst) to suppose such a pessimistic outlook when Sol almost acquired multiple planets with the conditions to bloom life.

How have you reached this conclusion? We have one data point in the Galaxy's historical record, and from that result, so far the odds of emergence are 1 for 1. A 100% chance.

Hmmn. Sounds like a Star Trek sort of thingy. What if, rather than a big galaxy of colorful fuzzies holding appendages and singing folk tunes, ET is more like a Stalin-cum-SuperEinstein sort of fellow, and altruism really isn't his "thing"?

 

It took millions of years for us to get any close to where we are now. Then we evolved extremely fast. Maybe in a million years, we might, who knows?

 

The vast majority of stars are main sequence stars - these are star like the Sun that are burning hydrogen into helium to produce their energy. Most stars spend 90% of their life as main sequence stars. A small percentage of stars 2/3% if I'm right die sooner than the sun.

Meaning it's not possible life could evolve before ten billion years and possibly moved elsewhere?

Planets around binary systems are likely to be common. There are 20 planets discovered around binary systems which isn't bad considering astronomers avoid searching such systems because the star-star interaction could hide the planet signatures. I think you'd need to explain or direct me to an article which comes up with solid science that life around as you say 75% of stars impossible.

You have branded billions of trillions "impossible" for life which leaves... billions of trillions potentially suitable.

Are you a betting man?

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I'm getting exhausted posting on this thread now so I'm out, but carry on... it's an interesting topic.

 

I find it hard to believe Sagan claimed that there are a million civilizations. He seems too smart to make an unsupported claim like that. I would be interested in finding out his basis for that claim, assuming that he did make it.

I have no idea of the percentage of various types of stars. I only know that massive ones burn out sooner, and that Sol is a common type of star. I think the ones that burn out in a few million years are rare, but I am not sure about the percentage which burn out in less than 5 billion, which seems to be required for the evolution of intelligent life.

I think that binary systems are more common than single stars. but I am not sure.

I wonder how well anybody understands the processes involved in the formation of solar systems. Is it known that planets other than gas giant are common?

Those who claim that intelligent life has occurred often should have some analysis to back up their claim, unless they want to state that their claim is based on faith. They should have some estimates of percentage of stars with lifetimes of 5 billion or more years, percentage of single star systems, percentage with planets, et cetera.

I thought I showed some good reasons to think that intelligent life is likely to be a rare occurrence. So far, all I have heard from the believers is that there are billions of stars, therefore intelligent life must be a common occurrence.

 

Actually one good supervolcano eruption (TOBA Circa: 72,000BC) and/or a large asteroid impact can throw the earth back into the stone ages quicker than you think. In terms of if ETI were out there transmitting narrow band radio signals for millions and even billion of years into the nearby universe.....??? If ETI had evolved to a level of technology sophisticated enough to send out narrow band radio signals out to 5,000 light years, then I think it's entirely possible that we should have picked up some of them by now. But the fact of the matter is, we haven't. So what should we conclude from this? There is probably 'No' ETI within 5,000 light years that have evolved enough technology to send out narrow band radio signals or there is 'No' ETI out there within 5,000 light years and/or there is 'No' ETI out there at all.

Okeydoke

 

Carl Sagan:

"There may be a million worlds in the Milky Way Galaxy alone which are at this moment inhabited by other intelligent beings" (Cosmos, episode XI)

 

A million would be one per hundred million suns. This is hardly an extravagant claim.

 

I think Carl Sagan was a little 'overly' optimistic in his views about ETI and his expectations about discovering it. If he were around today, he would probably be a little disappointed. So far todate, 'No' confirmed ETI messages to write home about.

Okeydoke

 

And now we have solar sails. So stop being so negative about it!!!

A few years ago, teletransportation was completely sci-fi. Now it might be a possibility. Solar sails is already possible and it was sci-fi in the turn of the century. So who knows?

I think we understand that. I do at least. But your view is a little bit more pessimistic then realistic...

Nope. They did it using conventional technology. That doesn't mean there is primitive life being developed somewhere around here. Fuck... they might even me in their "middle ages"! In a couple of centuries, they might be able to get some signals, who knows? But the point is that they can either be less advanced or more advanced, so you cannot really rule out the possibility.

Besides, 50 light years is not much compared to the universe, or even to the galaxy, for that matter.

Considering evolution, chances are that intelligence might be inevitable...

Our solar system is composed of a main sequence star. The most common kind in the universe. There's almost nothing around it for the next 4 light years. It still has all the elements that it has. So it's likely that our solar system is fairly common...

Massive stars are not common. Besides, their existance is important for us, as they produce the elements that we need for life. I'm sure one massive star is big enough to produce enough elements for a few solar systems.

Note that that is the majority of the solar system. Not only that, but our galaxy is not the only kind of galaxy....

Maybe...

A fairly advanced one might be able to send tight beams in all directions.

But anyways.... I see what you are saying, but you don't need to be so pessimistic. I would guess that we might make contact in the "near" future, but if we do, we still have some millions of years ahead (hopefully, eh?

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Hehehe... way too true....

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For how long have we been searching?

 

As I mentioned in an earlier post, most of the people who are involved in SETI research have optimistic views about finding ETI in our lifetimes. Carl Sagan is no stranger to SETI research and was just as eager to find ETI in his lifetime too. Since the birth of radio astronomy in 1932, unfortunately none ('No' confirmed ETI radio signals) have been found since Carl Jansky first introduced this new science. This combined with the possibility that ETI doesn't exist in our galaxy??? If this turns out to be the case, then all bets are off.

Okeydoke