by AgentR11 » Mon 30 Jun 2014, 16:55:49
$this->bbcode_second_pass_quote('joewp', 'A')nd I think Drake and Fermi were being a little species-centric thinking that intelligence is only defined by the ability to send radio waves.
To be fair, the only thing there is *any* chance of detecting is radio transmissions, and even those probably in only a modest section of the spectrum. Tech civilization could easily get to the point where virtually all radio transmission happens in the multi-ghz range; great for high bandwidth, short range and/or line of site, great if you have high transmitter density linked with physical fiberoptic (or better); absolutely horrible if you want to transmit unaimed, long distance, through humid air in a sea of localized interference.
Just think of our little phones, in just a few short years, we've gone from tapping out beep-beep-beep over powerful, long range, unaimed broadcasting antenna, to something that can receive and display an HD movie or transmit a long video-phone conversation on a battery measured in milliamp hours. The trend is obvious, the window for finding high power, unaimed, rf broadcasts isn't thousands of years... its decades. And its the physics of power, uniform throughout the universe, that make it so. Imagine how tiny a 5-10 decade long window is, over the observational life of a planet, or even the observational life of a planet with a known intelligent species well suited to making broadcasts. We've been around as us (basically) for 250,000 years or something, we've broadcasted high power, unaimed, for about 6 decades, and are now rapidly shifting to different technologies because the physics behind them provide so much more capability on so much less power. If a species out there starts observing the Earth in its time stream 4 decades from now, they probably won't find piddle for recognizable RF, unless we just feel generous and put a beep-beep beacon out in a solar orbit or something because we want to be friendly. (dumb idea, but it'd work).
We could stare right at a high tech, developed, large, industrial civilization, with billions of inhabitants, and see nothing.