ArcherB, you cannot tell by looking at a planet whether there is life there, especially not intelligent life. Do you know how many human constructions are visible from space today? And I'm talking near-Earth orbit. I believe it is one - the Great Wall of China. But it is definitely fewer than ten. And that's from looking from a few tens of thousands of miles. SETI explores across distances of millions of miles, absolute minimum. In most cases, it's at least 100 light years away. How do you construct a telescope to look at a planet that far away? You probably can't ever, and we certainly can't now or in the immediate future.
The only way to detect intelligent life is to find patterns of energy. In stars and other natural phenomena, energy transmissions are random - without any discernible pattern. The key is to find patterned information, as every transmission of any kind that contains information also contains a pattern, even if they aren't trying to broadcast that information to other systems.
SETI does not just analyze "radio signals." It analyzes a broad spectrum of electromagnetic energy waves - of which radio waves and visible light are merely portions. The frequency ranges examined are chosen by properties, because some frequencies are better at traveling through matter. That is why, for instance, light doesn't go through walls but radio waves do. And the more computational power at SETI's disposal, the more sky they can search and the more frequencies examined.
You cannot find any species in intragalactic space that does not utilize electromagnetic energy for communication, as we use for radio, television and a host of other reasons. We can barely DETECT planets outside our solar system there (although we're getting a lot better at it very quickly), let alone LOOK at these planets. Do you even know how we detect them? We look for the tiny wobble in the energy it puts out caused as the planet rotates around it, pulling ever so slightly. We can't see the planets, and we can only make educated guesses about their size and distance from the star based on the speed and degree of the wobble. It is likely that, from this distance, direct observation of these planets is impossible due to the massive amount of radiation put out by the stars. It's orders of magnitude more difficult than trying to observe Mercury. Orders of magnitude more orders of magnitude more difficult. We can't tell if there's life on MARS just by looking through a telescope, and you think we can detect life a trillion times farther away using that same method? The ONLY way to detect these other species with any technology we have or can even think about is to analyze energy transmissions that leak out into space and find patterns there.
Your notion of "radio waves" is bound by too tight a clenching to the meaning of the word "radio" and a failure to understand the nature of patterned information. Radio waves will always be used, as radio waves are merely a certain section of the spectrum of electromagnetic emissions that we've labeled because they happened to be of good frequency to transmit audio signals for the first wireless technologies humans developed. "Radio waves" are the ONLY way energy gets transmitted, period. Radio waves are just electromagnetic emissions with really long wavelengths compared to visible light and microwave emissions. It's the only way to get information through space. At least, according to the Standard Model. That may be (probably will be, I would say) be usurped someday, but that doesn't mean we go about assuming all other sentient species exclusively use some method of communication we know nothing about. If they're that advanced, they went through their "radio wave" period of technology, too, and I guarantee that they struck upon the idea that other species may be out there, and some subset would probably have the same questions we have, and look through space for something that indicated somebody else was out there. And one of those ways is, and will always be patterned electromagnetic signals broadcast out into th
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Frick. Wall of text.
That's what I get for talking about with in my f i r s t p o s t, and not using preview.
ArcherB, you cannot tell by looking at a planet whether there is life there, especially not intelligent life. Do you know how many human constructions are visible from space today? And I'm talking near-Earth orbit. I believe it is one - the Great Wall of China. But it is definitely fewer than ten. And that's from looking from a few tens of thousands of miles. SETI explores across distances of millions of miles, absolute minimum. In most cases, it's at least 100 light years away. How do you construct a telescope to look at a planet that far away? You probably can't ever, and we certainly can't now or in the immediate future. The only way to detect intelligent life is to find patterns of energy. In stars and other natural phenomena, energy transmissions are random - without any discernible pattern. The key is to find patterned information, as every transmission of any kind that contains information also contains a pattern, even if they aren't trying to broadcast that information to other systems. SETI does not just analyze "radio signals." It analyzes a broad spectrum of electromagnetic energy waves - of which radio waves and visible light are merely portions. The frequency ranges examined are chosen by properties, because some frequencies are better at traveling through matter. That is why, for instance, light doesn't go through walls but radio waves do. And the more computational power at SETI's disposal, the more sky they can search and the more frequencies examined. You cannot find any species in intragalactic space that does not utilize electromagnetic energy for communication, as we use for radio, television and a host of other reasons. We can barely DETECT planets outside our solar system there (although we're getting a lot better at it very quickly), let alone LOOK at these planets. Do you even know how we detect them? We look for the tiny wobble in the energy it puts out caused as the planet rotates around it, pulling ever so slightly. We can't see the planets, and we can only make educated guesses about their size and distance from the star based on the speed and degree of the wobble. It is likely that, from this distance, direct observation of these planets is impossible due to the massive amount of radiation put out by the stars. It's orders of magnitude more difficult than trying to observe Mercury. Orders of magnitude more orders of magnitude more difficult. We can't tell if there's life on MARS just by looking through a telescope, and you think we can detect life a trillion times farther away using that same method? The ONLY way to detect these other species with any technology we have or can even think about is to analyze energy transmissions that leak out into space and find patterns there. Your notion of "radio waves" is bound by too tight a clenching to the meaning of the word "radio" and a failure to understand the nature of patterned information. Radio waves will always be used, as radio waves are merely a certain section of the spectrum of electromagnetic emissions that we've labeled because they happened to be of good frequency to transmit audio signals for the first wireless technologies humans developed. "Radio waves" are the ONLY way energy gets transmitted, period. Radio waves are just electromagnetic emissions with really long wavelengths compared to visible light and microwave emissions. It's the only way to get information through space. At least, according to the Standard Model. That may be (probably will be, I would say) be usurped someday, but that doesn't mean we go about assuming all other sentient species exclusively use some method of communication we know nothing about. If they're that advanced, they went through their "radio wave" period of technology, too, and I guarantee that they struck upon the idea that other species may be out there, and some subset would probably have the same questions we have, and look through space for something that indicated somebody else was out there. And one of those ways is, and will always be patterned electromagnetic signals broadcast out into th