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have they found anything?

Safe-Keeper said:
The existence of elk as a species was not in question - the existence of elk in the hunting area was.

Appeals to tradition and nature constitute logical fallacies. I subscribe to a Scandinavian-wide history magazine, and this issue featured a quote from a physician who said it was perfectly natural that half of the country's children died before the age of eight, and that it was pointless to worry about this since it was the way nature worked.

Christianity costs billions of dollars, doesn't it? Have you proven the existence of God yet?

No, because SETI doesn't really believe in aliens. SETI says there might be aliens out there, technically, and that we should investigate the possibility. This is a far cry from believing in a specific god. Look at it this way: if SETI suddenly sat down and wrote a book describing what the aliens looked like, where they lived, how their mindsets worked, how they evolved and what wars and other struggles and triumphs they went through, what they wanted of us, and how their civilization would end - all without having seen a single alien or even finding proof they existed in the first place - then it would be a decent comparison to Christendom. As it stands, though, the SETI stance is more reminiscent of agnosticism.

How far can our stronger radio signals travel, anyhow? I heard in a documentary (Life Without People, or whatever it was called) that they dissipate into background noise after only a light year or two?
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I'm not to sure about radio signals, but light travels for billions of years without dissipating.
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Safe-Keeper said:
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No, because SETI doesn't really believe in aliens. SETI says there might be aliens out there, technically, and that we should investigate the possibility. This is a far cry from believing in a specific god.
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True, they don't claim because they aren't sure.


Look at it this way: if SETI suddenly sat down and wrote a book describing what the aliens looked like, where they lived, how their mindsets worked, how they evolved and what wars and other struggles and triumphs they went through, what they wanted of us, and how their civilization would end - all without having seen a single alien or even finding proof they existed in the first place - then it would be a decent comparison to Christendom.
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False analogy. Christianity doesn't operate on the basis of non-proof as you describe. The basis for Christian belief in God is described by Paul in the letter to the Roman congregation:

Romans 1:20
For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:

So did the Hebrews:

Psalm 19:1
The heavens declare the glory of God; and the firmament sheweth his handywork.

As it stands, though, the SETI stance is more reminiscent of agnosticism.

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True.
 
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I don't have anything to add to this thread. Mostly I just wanted to get subscribed to it.

El Greco pretty much summed up my thoughts. Probably there's some sentient technologically capable life out there but I think it's very unlikely to be detected in my lifetime.

As time as gone on, my various readings on this subject have gradually reduced my expectation of any kind of extraterrestrial contact. Based on an article in Scientific American that I read a few years ago it seems that only stars in a narrow band of the milky way are viable for life as we know it. Then for life to exist as we know it some rather fortuitous circumstances need to surround the planet that life exists on. And I suspect that they don't occur very often. And just the simple fact that SETI has been listening for a long time and hasn't found anything is beginning to provide negative evidence for the existence of civilizations near enough for us to detect.
 
Because of the almost infinite number of galaxies out there there is bound to be, somewhere a life producing planet orbiting a sun similar to our own.
But if our earth is any example animal life, let alone intelligent animal life, would be almost impossible. Seti will not ever find another earth. Sure there may be billions of planets with simple life like bacteria in existence. The chance of another earth forming and intelligent beings evolving is probably a trillion to one chance.
A few years ago a very good book was released titled; ''Rare Earth.'' by two respected scientists named, Prof. Peter D. Ward and Astronomer Prof. Donald Brownlee of University of Washington in Seattle. I thoroughly recommend this book to inquiring minds such as mine.
 
As a theist I see no difficulty whatsoever in there being life. Any type of life, whether intelligent, or non intelligent since from my standpoint that all depends on God's decision.

However, I do recognize that there are many areas in our universe which seem to be hostile to life as we know it. Such as the inner galactic regions where radiation is too intense due to the density of number of stars found there. Or on those planets recently discovered which display extremely elongated elliptical orbits which would cause them to be showered by lethal radiation on one extreme while freezing on the other. Or On planets whose orbits are too near their star making them veritable ovens. Or on planets that might be circling some cepheid variable, those stars which expand and shrink in response to what appears to be some inner core instability which makes the tug and war between outward radiation and gravity a dramatic one. All these conditions seem to mitigate against most earth-based forms of life being able to exist there.
 
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I on the other hand being an atheist believe no god is necessary for the start of life in any planet if the conditions are right. Like I said in my previous post, bacterial life could be in more abundant places than Drake ever imagined , perhaps in our own solar system. After all there have been more than a couple of life starting cycles right here on earth after catastrophic collisions with huge asteroids that extinguished all life that had maneged a toehold beforehand and had to start over. But Animal life is an entirely different matter and needs billions of years to evolve with a steady state sun like ours which according to a few astronomers are rare in our galaxy.
 
ambnp said:
Because of the almost infinite number of galaxies out there there is bound to be, somewhere a life producing planet orbiting a sun similar to our own.
But if our earth is any example animal life, let alone intelligent animal life, would be almost impossible. Seti will not ever find another earth. Sure there may be billions of planets with simple life like bacteria in existence. The chance of another earth forming and intelligent beings evolving is probably a trillion to one chance.
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That's still pretty good odds.

ambnp said:
But Animal life is an entirely different matter and needs billions of years to evolve with a steady state sun like ours which according to a few astronomers are rare in our galaxy.
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Yellow stars like our sun are among the most common in the universe.
 
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Hi, why bother with setti, when we know the gov. works with ET. The moon rockets saw saucer's sitting on the edge of a crator watching them. So many people have had contact, can't all be stupid. Our spirit guides say they are real. The Gov. next act may be a false ET. invasion, time will tell. Cheers Old Bob
 
godless dave said:
That's still pretty good odds.




Yellow stars like our sun are among the most common in the universe.
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I thought suns like ours are quite rare. Yellow suns are very common, but their mostly giants and short lived unlike our sun which will probably live in the vicinity of 10 billion years. Even if your right, it;s complement of planets have to be something like our solar system. With gas giants like Jupiter and rocky planets like earth at just the right distance from it's sun to have any chance of life evolving.
 
Old Bob said:
Hi, why bother with setti, when we know the gov. works with ET. The moon rockets saw saucer's sitting on the edge of a crator watching them. So many people have had contact, can't all be stupid. Our spirit guides say they are real. The Gov. next act may be a false ET. invasion, time will tell. Cheers Old Bob
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Bob is this a wind-up, or are you serious? Honestly, I can't tell, not knowing you.

Whichever- welcome to the forum.
 
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godless dave said:
That's still pretty good odds.
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With an estimated 100 billion stars in our galaxy (1x1011), you would need only ten galaxies to get 1 trillion (1x1012). Now, I don't know how many galaxies there are, but let's use the conservative estimate of 4 million (probably billions)

Galaxy Estimate

and pull 1 in 1000 stars as "candidates" out of my butt...

(1x1011x4x106)/(1x103x1x1012) = 400 potential civilizations!

Not bad! Too bad we're too far apart to meaningfully communicate. My guess is that the number of planets with something resembling life is actually much higher... but that's a guess.
 
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Jimbo that's what I perceive as well. because of the astronomical numbers we are dealing with, the odds greatly favour probably millions of other life bearing planets scattered throughout the cosmos. But the nearest one to us may be in the Oder of anything between 1 to 5 or higher billion light years away.
 
We were discussing this recently and my son said the following:

"If numbers determine probability, and probability is so great due to the astronomical numbers involved, then we should expect the vacuum to be abuzz with their communications. Yet we are met with an unnerving deathly silence instead."

Given the eons that transpired before we appeared in recent universal history and developed signal-detection abilities some type of communication signal should be easily evident.

We have to remember that our star is a second-generation star supposedly produced from the material of another star that went supernova. Prior to that there was a universe with billions of galaxies each containing billions of stars with who knows how many planets in orbit about them.

Our sun is said to be approx. five billion years old. If indeed the top estimates of fifteen-billion years for the age of our universe is correct, then that leaves a full ten-billion years prior to the sun's ignition for civilizations to develop. A billion is a thousand-million. So that means that ten-times a thousand-million years transpired before our sun ignited its fusion engine. Two-thousand-million years more for the earth to take form. Three-thousand-million more for us to get to the present.

That by itself makes the silence even more eerie.

BTW

I am aware of the diverse conditions of the universe prior to the sun's appearance as a second generation star. So please deduct whatever time is necessary from my estimates.
 
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An interesting thought Radrook, but it has a flaw I think.

Signal intensity will fall off with distance. At some point the intensity of the signal falls below the local noise level for that particular frequency and the signal becomes undetectable.

So there could have been lots of civilizations that have come and gone that produced a signal that passed us by that can't be distinguished from the noise.

This is a somewhat complicated issue that I know only a little bit about. I don't remember the numbers now but I don't think SETI has much hope of detecting a signal from a planet that is much more than 50 light years away which of course is a minuscule distance compared to the distances of the galaxy and the size of the galaxy is minuscule compared to the overall universe.

Even at those kind of distances a civilization with really large antennae that they have decided to aim at us is required or a civilization that is sending out massively powerful signals omnidirectionally is required.

I wish I could remember more of the actual numbers here but whatever the actual distances that allowed for the likely detection of a signal they were hugely less than the size of the galaxy. This is one of the reasons that I think it is so unlikely that SETI will ever detect a sentient civilization.
 
This is total speculation, and laugh if you must..but...

What if looking for radio signals is the wrong way to go...perhaps radio transmission is just the first step in communication?

For instance, lets say the LHC validates the Higgs field hypothesis...couldn't it hypothetically be concievable that the field itself could transmit data or communications with a suffciently advanced technology...or perhaps something utilizing entanglement of electrons?

I was just thinking about this after watching some Borg episodes...don't mind me...
 
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thesyntaxera said:
This is total speculation, and laugh if you must..but...

What if looking for radio signals is the wrong way to go...perhaps radio transmission is just the first step in communication?

For instance, lets say the LHC validates the Higgs field hypothesis...couldn't it hypothetically be concievable that the field itself could transmit data or communications with a suffciently advanced technology...or perhaps something utilizing entanglement of electrons?

I was just thinking about this after watching some Borg episodes...don't mind me...
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Right now the only two kinds of signals that might be used from what I know would be electro-magnetic and neutrino beams. I've never heard of anybody actually proposing a neutrino beam but it seems at least conceivable since there have been at least proposed experiments to see if neutrinos could be produced in one place, transmitted through the earth and detected at another location.

But there have been suggestions that there are other possibilities than the microwave frequencies that are mostly commonly scanned by SETI efforts. One such idea is optical laser pulses. This is a technical paper about the possibility:
http://seti.harvard.edu/oseti/tech.pdf

I didn't read through the whole thing but they propose that detection of emitters within a radius of about 1000 LY is possible.

Here is a document that I found discussion the detection range limits for different kinds of earth produced electro magnetic radiation:

http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html

The actual table is about 2/3 of the way through the paper. I put a copy of the table below:

-------------+--------------+-----------+--------+--------+-----------+
Source | Frequency | Bandwidth | Tsys | EIRP | Detection |
| Range | (Br) |(Kelvin)| | Range (R) |
-------------+--------------+-----------+--------+--------+-----------+
AM Radio | 530-1605 kHz | 10 kHz | 68E6 | 100 KW | 0.007 AU |
-------------+--------------+-----------+--------+--------+-----------+
FM Radio | 88-108 MHz | 150 kHz | 430 | 5 MW | 5.4 AU |
-------------+--------------+-----------+--------+--------+-----------+
UHF TV | 470-806 MHz | 6 MHz | 50 ? | 5 MW | 2.5 AU |
Picture | | | | | |
-------------+--------------+-----------+--------+--------+-----------+
UHF TV | 470-806 MHz | 0.1 Hz | 50 ? | 5 MW | 0.3 LY |
Carrier | | | | | |
-------------+--------------+-----------+--------+--------+-----------+
WSR-88D | 2.8 GHz | 0.63 MHz | 40 | 32 GW | 0.01 LY |
Weather Radar| | | | | |
-------------+--------------+-----------+--------+--------+-----------+
Arecibo | 2.380 GHz | 0.1 Hz | 40 | 22 TW | 720 LY |
S-Band (CW) | | | | | |
-------------+--------------+-----------+--------+--------+-----------+
Arecibo | 2.380 GHz | 0.1 Hz | 40 | 1 TW | 150 LY |
S-Band (CW) | | | | | |
-------------+--------------+-----------+--------+--------+-----------+
Arecibo | 2.380 GHz | 0.1 Hz | 40 | 1 GW | 5 LY |
S-Band (CW) | | | | | |
-------------+--------------+-----------+--------+--------+-----------+
Pioneer 10 | 2.295 GHz | 1.0 Hz | 40 | 1.6 kW | 120 AU |
Carrier | | | | | |
-------------+--------------+-----------+--------+--------+-----------+

Notice that a one terawatt signal transmitted from a Arecibo sized antenna is required to reach a range of 150 light years.

So you not only have to envision an advanced civilization. You have to envision an advanced civilization that decides to construct a vastly powerful transmitter, a massive antenna and the desire to use them to engage in what is likely to be only one way communication with a fellow advanced civilizaton.

Seems like a long shot to me.
 
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I believe you have better odds at winning lotto than Seti has of finding intelligent lifeforms of any kind.
 
davefoc said:
Right now the only two kinds of signals that might be used from what I know would be electro-magnetic and neutrino beams. I've never heard of anybody actually proposing a neutrino beam but it seems at least conceivable since there have been at least proposed experiments to see if neutrinos could be produced in one place, transmitted through the earth and detected at another location.....snip....
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Thanks for the information. It really put's into perspective the difficulty and improbability of the task before them.

I am still hopefull, and I will still be running my seti @home just in case.

To bring up another idea...the drake equation...how respectable is it? I have read that there could potentially be as many as 30 billion earth like planets in our galaxy, and it just makes me wonder...
 
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thesyntaxera said:
Thanks for the information. It really put's into perspective the difficulty and improbability of the task before them.

I am still hopefull, and I will still be running my seti @home just in case.

To bring up another idea...the drake equation...how respectable is it? I have read that there could potentially be as many as 30 billion earth like planets in our galaxy, and it just makes me wonder...
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With all due respect to Mr Drake, I believe he is wrong. If that number was correct we would by now be telling our visitors to go away, there would be literally thousands of them knocking on our doors. Anyway, I think he mentions that number for the whole universe, not our galaxy alone which has an estimated 3 billion stars.
 
ambnp said:
With all due respect to Mr Drake, I believe he is wrong. If that number was correct we would by now be telling our visitors to go away, there would be literally thousands of them knocking on our doors. Anyway, I think he mentions that number for the whole universe, not our galaxy alone which has an estimated 3 billion stars.
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from the wikipedia article on the milky way:
The stellar disk of the Milky Way galaxy is approximately 100,000 light years in diameter, and is believed to be, on average, about 1,000 light years thick.[8] It is estimated to contain at least 200 billion stars[9] and possibly up to 400 billion stars,
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Still, based on my understanding 30 billion earth like planets sounds like way too many. The likely habitable location range for an earth like planet in our solar system is just a little beyond the earth and a little closer to the sun than the earth. So even if earth like planets occur occasionally they have to have an orbit radius that is pretty close to earth's to be habitable for advanced life similar to us. (I guess the range is somewhat larger if we're only talking bacteria or maybe creatures that are vastly different than us).

But that's not enough they have to be in the habitable zone of the galaxy and this places additional restrictions on the number. Too far from the galactic center and not enough heavy elements for life. Too close and radiation fries your brains.
 
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