have they found anything?

[amb]

To carry that story a little bit further. What about a level of intelligence equivalente at least to us. What are the chances of that happening more than once? A random occurrence of that happening twice or more times must be like winning the lotto thrice in someones lifetime.
To believe otherwise creates a feeling of the universe been designed with life destined to occur where ever conditions seem right. That sounds like a designer creating just such a universe. I feel that intelligent life was a random accidente that is not likely to ever occur again. But given the countless galaxies out there with trillions of stars, there is bound to be another earth some where in the cosmos. I would hazard a guess and say perhaps a million at most.

 

[shadron]

Better luck in reference to what? Just because you couldn't find what I repeatedly read in one of his books doesn't mean I made it up. Actually I read Foundations Edge and don't recall coming across that statement. The statement wasn't made in one of his sci fi books. If memory serves me right, it was a book about religion where he was hell-bent on proving the Bible is drivel in terms of scientific descriptions. Asimov has, I believe. approximately three-hundred books in print. So finding a single expression as the one I referred to is a daunting task. Unfortunately I can't recall the exact book I read it in some twenty years ago. However, I'll start a search of my own and see if I can track it down.

Well then, Radrook, have at it and let us know what you come up with. Since you seem o be somewhat bent out of shape by his opinions about the bible, might I suggest "Asimov's Guide to the Bible" in two volumes? BTW, Asimov's own count of his books was somewhat in excess of 500, but that could be tempered by the fact that he was rather vain and possessive about that list; see the comment at http://stason.org/TULARC/education-books/isaac-asimov/1-1-Just-how-many-books-did-Asimov-write.html.

As to why you should be so insulted when someone quesions your source, well, you are the one who made the assertion, so I presume you are the one to back it up. My admittedly superficial search led me to he belief that you are possibly mistaken, but if you aren't, then it's your job to substantiate it, not mine. It looks to me like you're just taking a cheap shot over the bow. I'll enjoy debating your proof that he was unfairly driveling all over the bible; heaven knows the Good Book's chock full of scientific gold nuggets.

Oh, and BTW, read the jacket blurb of Foundation's Edge for the quote; not the content, and not even his own writing. Or just google for it. Amazon will quote it for you.

 

[shadron]

To carry that story a little bit further. What about a level of intelligence equivalente at least to us. What are the chances of that happening more than once? A random occurrence of that happening twice or more times must be like winning the lotto thrice in someones lifetime.
To believe otherwise creates a feeling of the universe been designed with life destined to occur where ever conditions seem right. That sounds like a designer creating just such a universe. I feel that intelligent life was a random accidente that is not likely to ever occur again. But given the countless galaxies out there with trillions of stars, there is bound to be another earth some where in the cosmos. I would hazard a guess and say perhaps a million at most.

What, Amb, I have to believe that intelligent life is extremely rare or be a IDer? I think that's a rather jaundiced viewpoint. I would think rather that the intelligence lottery could be won by any planet with perhaps restrictive, but not necessarily rare, set of conditions; that intelligence is, rather than a low probability happening, but rather inevitable under those conditions, and further, that the conditions may be more relaxed than we can know now because we haven't investigated more than one such case. Any reasoning to back up your feelings, or is this just a swag (see http://www.urbandictionary.com/define.php?term=SWAG method)?

 

[arthwollipot]

But animal life is a complete different kettle of fish. The chances of animal life ever occuring again a extreemley rare.

What makes you think that anything "above" the microbial stage will resemble any kind of plant or animal here on earth?

 

[I Ratant]

Other than pollution of the electromagnetic spectrum with sitcoms (W#dtoei fow***#s L[]%)and the alien version of Oprah, what would be the indicators SETI could detect that would show 1) life or 2) intelligent life?

 

[davefoc]

Other than pollution of the electromagnetic spectrum with sitcoms (W#dtoei fow***#s L[]%)and the alien version of Oprah, what would be the indicators SETI could detect that would show 1) life or 2) intelligent life?

It is very unlikely that alien civilizations are going to pick up television transmissions according to the table from this site:
http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html

see copy of table in this post:
http://www.internationalskeptics.com/forums/showpost.php?p=3557598&postcount=82

Note the range for UHF television (2.5 AU) and the range for the UHF carrier (0.3 LY). Neither estimate is enough to make it out to the nearest star. They don't list a range for VHF television but FM radio is in the middle of the VHF television band and the estimated range for that is 5.4 AU. Again no where near enough to make it to the first star.

The optimistic ranges for detecting a nearby planet are based on either massively powerful transmitters or highly focused outputs from large transmitters.

The calculations that I made in a previous post suggested that one would need an Arecibo sized antennae with a 250,000 watt transmitter to be able to send a detectable signal to a planet as far away as 150 light years.

This is easily with the capability of earth's technology. The Arecibo antennae has only limited steering capability. I think it is mostly constrained by the direction it is pointing as it rotates with the earth so there are lots of potential targets it couldn't be aimed at. The 250,000 watts could be pulsed so that no where near 250,000 watt of continuous power would be required. But will the powers that be that control enough of earth's resources ever feel like funding a major effort to transmit to unknown alien civilizations?

Post where the calculation was discussed:
http://www.internationalskeptics.com/forums/showpost.php?p=3565450&postcount=94

I think the most likely intentionally produced electro magnetic radiation produced on the earth today that could be detected by an alien civilization would be from radars. These are focused and some of them are very powerful. I notice that the table lists the range of a particular weather radar as .01 light years. That doesn't validate my guess because it lists the range of a UHF carrier as .3 light years but I suspect that other radars would do better. Military radars might do much better.

But even if the ranges of military radars are much greater than what is listed for the weather radar in the table, the ranges are still probably much too small to get much beyond the nearest stars.

In another post I linked to an article discussing the feasibility of a laser transmitter to reach stars. If the powers that be wanted to dedicate some resources to this idea the authors suggest that we might hit a 1000 light years with a currently feasible optical laser. I think that bumps the stars for which a signal might be detected from about a 1000 that lie within 100 light years to about a 100,000 that lie within a 1000 light years.

The article on the possibility of optical SETI:
http://seti.harvard.edu/oseti/tech.pdf

 

[Radrook]

Well then, Radrook, have at it and let us know what you come up with. Since you seem o be somewhat bent out of shape by his opinions about the bible, might I suggest "Asimov's Guide to the Bible" in two volumes?

You have a quaint way of describing how you assume other people who disagree with you think. As for Asimov's Guide to the Bible, I already read it and wasn't impressed. Perhaps because of his impossible planet statement which requires that one put one's brain on hold in order to believe what he himself had trouble believing but told others to believe anyway.

BTW, Asimov's own count of his books was somewhat in excess of 500, but that could be tempered by the fact that he was rather vain and possessive about that list; see the comment at http://stason.org/TULARC/education-books/isaac-asimov/1-1-Just-how-many-books-did-Asimov-write.html.

I was going by memory of his autobiography. So if that's the number it says then I guess one should take him at his word.

As to why you should be so insulted when someone quesions your source, well, you are the one who made the assertion, so I presume you are the one to back it up. My admittedly superficial search led me to he belief that you are possibly mistaken, but if you aren't, then it's your job to substantiate it, not mine.

I am not averse to having my sources challenged. What I am averse to is having devious ulterior motives and unethical modus-operandies attributed to me.

It looks to me like you're just taking a cheap shot over the bow.

That's an example right there.

I'll enjoy debating your proof that he was unfairly driveling all over the bible; heaven knows the Good Book's chock full of scientific gold nuggets.

I didn't say drivelling. That Im seeking desperately to debate the Bible on a SETI thread is your idea not mine.

Oh, and BTW, read the jacket blurb of Foundation's Edge for the quote; not the content, and not even his own writing. Or just google for it. Amazon will quote it for you.

I have no doubt that it might appear on the blurb.

 

[RecoveringYuppy]

And of course, a large number of these stars are binary systems. Not suitable for animal life of any kind.

I see this claim made a lot but what is the basis for it? Why would binary star systems necessarily be unsuitable for life (animal or otherwise)?

ETA (sorry for the repetition, didn't realize there was a second page to the thread)

 

[arthwollipot]

My understanding is that some binary stars are far enough apart from each other that each could potentially support a small planetary system. But I could be wrong about that.

When the stars are closer together, the three-body problem means that any planet influenced by the gravity of two stars would likely have a chaotic orbit, or may be hurled out of the system altogether. Any such planet (that stays in the system) would not have a consistent day/night or seasonal cycle, and would not be suitable for life as we know it.

Other kinds of life might be just fine though. We don't know.

 

[RecoveringYuppy]

Seems to me that there'd be a significant number of binaries that could avoid those issues. Rigil Kentaurus has two sun like stars orbiting at about the separation of the Sun and Uranus. That's far enough away that an Earth like planet would still have a significant day/night cycle and could have a stable orbit. Not sure how typical that system is.

The nights on such a system would occasionally have more light than our full moon but still, even at it's brightest, it would never eliminate a very definite day/night cycle.

ETA: http://en.wikipedia.org/wiki/Binary_star citation 60 puts the percentage of binary stars with possible stable orbits at 50-60%

 

[arthwollipot]

There you go.

 

[amb]

What makes you think that anything "above" the microbial stage will resemble any kind of plant or animal here on earth?

If the history of the Earth could be played back like a tape recorder, from the very beginning. We may not even be here having this discussion.
It could not possibly happen exactly the same way again. Remember, it was a hit from a huge asteroid that sterilized the earth and killed off the dinosaurs. It was not until the dino's disappeared that made possible the emergence of homo sapiens. Life as we know it, requires the conditions that exist here on earth. The tilt of earths wobble that gives us the seasons, the right distance from our very stable sun which has a limited amount of life friendly ultra violet light, a gas giant [Jupiter] that acts like a vacuum cleaner thereby ensuring that a large amount of asteroids don't hit us as often, giving the earth enough time for animal life to evolve.
Here is my list of why I believe we may be unique in this galaxy at least.
1. Right distance from our sun.
2. Right planetary mass.
3. Plate tectonics.
4. Right mass of our star.
5. Jupiter-like neighbor.
6. Oceans, [ not to much. Not to little.]
6. Stable planetary orbits. [ Giant planets do not create orbital chaos.]
7. A Mars. [Small neighbor as possible life source to seed an Earth like planet, if needed.]
8. And last but by no means least. A large Moon. [At a very right distance to stabilize the Earths tilt.]
9. Seasons not too severe.
10. Our atmosphere.
11. Right position in galaxy. [ not in center, edge or halo.]
12. The exact amount of carbon. [ Enough for life. Not enough for runaway greenhouse as Venus has]
13. Evolution of oxygen. [Invention of photosynthesis. Not too much or too little. Evolves at the right time.]
14. Wild cards. [Snowball Earth. Cambrian explosion. Inertial interchange event.]
Among many other reasons. We still don't know exactly where life began. Was the Earth seeded by asteroids or meteorites? Did it start here in a million coincidences with inorganic elements somehow becoming organic and then evolution taking over to produce what now exists on Earth?
When I was a kid, I always believed that if life [ especially intelligent life] was abundant in the universe, then there was a god. If not, we are an accident or a freak of the laws of physics.

 

[LarianLeQuella]

Again amb, your list seems to indicate a very earth-centric view of life. Since we only have ONE datapoint at the moment, how can you conclusively say your list is a requirement for intelligent life? All the items you list are the things that gave us OUR kind of life. It's like a recipe for chocolate chip cookies. You only post your mother's secret family version forgetting there are hundreds (if not thousands) of variations on chocolate chip cookies, not to mention that there is also oatmeal raisin, peanut butter, and millions of variations of even other types of cookies.

Now, at this moment we can't say one way or another for sure. As davefoc posted, even our electromagnetic pollution isn't really that detectable that far away. In order for radio signals to be detectable with any degree of certainty, they need to be deliberately beamed. As far as I am aware, even us humans have only done that once...

 

[davefoc]

Again amb, your list seems to indicate a very earth-centric view of life. Since we only have ONE datapoint at the moment, how can you conclusively say your list is a requirement for intelligent life? All the items you list are the things that gave us OUR kind of life. It's like a recipe for chocolate chip cookies. You only post your mother's secret family version forgetting there are hundreds (if not thousands) of variations on chocolate chip cookies, not to mention that there is also oatmeal raisin, peanut butter, and millions of variations of even other types of cookies.

Now, at this moment we can't say one way or another for sure. As davefoc posted, even our electromagnetic pollution isn't really that detectable that far away. In order for radio signals to be detectable with any degree of certainty, they need to be deliberately beamed. As far as I am aware, even us humans have only done that once...

True, perhaps about amb's geocentric thought process, but it is a nice list that organizes information that I've seen in various places. Those ideas are at least reason to suspect that intelligent life is very rare and intelligent life that exists at the same time is certainly even rarer.

 

[JoeTheJuggler]

The chances of animal life ever occuring again a extreemley rare.

I keep saying the same thing, but I'll make the point again: What exactly is "extremely rare"? 1 in a million? 1 in ten million?

Is it maybe more common for animal life and civilizations with radio communication technology to arise but not survive (or broadcast) for long periods of time?

Remember the numbers involved. Complex life and even intelligence could be rare enough never to encounter another such form of life, but still happen thousands or tens of thousands of times in the galaxy.

The significance of SETI's not finding a signal yet is pretty limited. We've only been listening for a teensy-tiny fraction of the existence of our solar system, and only have the ability to detect signals relatively close to us.

 

[JoeTheJuggler]

Here is my list of why I believe we may be unique in this galaxy at least.
1. Right distance from our sun.
2. Right planetary mass.
3. Plate tectonics.
4. Right mass of our star.
5. Jupiter-like neighbor.
6. Oceans, [ not to much. Not to little.]
6. Stable planetary orbits. [ Giant planets do not create orbital chaos.]
7. A Mars. [Small neighbor as possible life source to seed an Earth like planet, if needed.]
8. And last but by no means least. A large Moon. [At a very right distance to stabilize the Earths tilt.]
9. Seasons not too severe.
10. Our atmosphere.
11. Right position in galaxy. [ not in center, edge or halo.]
12. The exact amount of carbon. [ Enough for life. Not enough for runaway greenhouse as Venus has]
13. Evolution of oxygen. [Invention of photosynthesis. Not too much or too little. Evolves at the right time.]
14. Wild cards. [Snowball Earth. Cambrian explosion. Inertial interchange event.]

First, in a universe with hundreds billions of galaxies and a galaxy with roughly 100 billion stars, why on Earth (so to speak) would you suspect that this constellation (so to speak) of conditions is unique? On what do you base that assumption?

Second, most of the items you list are not at all required for life to arise. Some of them aren't even required for our kind of life to have arisen. Number 10, for example. Since life arose on Earth "our kind of atmosphere" has changed dramatically. Related to that, number 13. First oxygen is an element and "evolved" in the hearts of stars going nova and creating heavier elements. Oxygen gas is O2, again not something that "evolved"--it's just chemistry. What do you mean by too much or too little? I suggest you read up on ecology. O2 is highly reactive and poisonous to many (probably most) forms of life on Earth. Organisms that rely on it evolved to be fittest in an atmosphere with O2 in it. There was no "coincidence" about it.

I find particularly troubling your point number 7. For this wild speculation (that life on Earth was seeded from life on Mars) to be true, you'd need to accept that there are 2 planets in our solar system capable of sustaining life. And you somehow use that point to argue that life on Earth is unique? Sorry, that's just illogical; that is, it's a contradiction. Also, was life on Mars seeded from somewhere else? Seems to me if you start speculating that life can be seeded from one planet to another, you're again arguing that life is relatively common and not at all unique to Earth.

 

[RecoveringYuppy]

... and only have the ability to detect signals relatively close to us.

How far away we can detect a signal is more a function of the transmitter than the receiver. If some distant civilization was working to make themselves known, they could arrange a single we couldn't miss.

 

[davefoc]

How far away we can detect a signal is more a function of the transmitter than the receiver. If some distant civilization was working to make themselves known, they could arrange a single we couldn't miss.

I take it you've read through the links and posts directed to this issue.

You are right that a sufficiently motivated group of sentient entities with the appropriate technology on a distant planet could make themselves known to us if they resided within a range of a 1000 light years or so. But the effort required is far beyond anything that civilizations on earth are seriously contemplating right now.

One reason for that is even if the effort succeeded in reaching a distant planet there is very unlikely to be a return signal and even if there was one the return signal may very well arrive after everyone is dead when the first signal was sent.

And it is important to realize that the receiver is an essential part of the issue. Antennas have a gain characteristic which is really a measure of their ability to focus. The reason that focus is so important for a receiving antenna is that the limiting factor on reception is noise and not gain. Gain is cheap and readily available, but at some point the signal is lost in the noise and can't be retrieved. Highly directional receive antenna (per force huge) improve the signal to noise ratio enormously and vastly increase the range that a signal can be detected at. Also, when trying to tease out a signal from a distant source out of the noise, the noise of the receiver itself can be a significant issue and that is why detectors in this kind of receiver are cryogenically cooled.

The point of all this is that even if the technology existed on two planets with sentient entities that were within a thousand light years or so of each other it is still unlikely that they would detect each other given that they both had earth like technology and earth like inclinations as to the desirability of making themselves known to distant planets.

 

[arthwollipot]

We currently have not worked out any way that life can exist without the specific arrangements of carbon atoms that earth-based life uses, so the geocentric assumption of carbon-based life is a reasonable one for the moment. But that doesn't mean that non-DNA based or even non-carbon based life doesn't or can't exist. It's just that we haven't worked out how it could happen.

 

[RecoveringYuppy]

@davefoc

Mostly agreed, but why 1000 light years?

And I'm not sure about setting up a beacon that would make us unmissable (given enough time) is beyond anything being contemplated by any civilization. A small show at such a project was actual done for a few minutes at Arecibo. I would think that if someone put their mind to it a beacon project would fall in the range of private funding (ala SETI).