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Why We're Looking For ET All Wrong
StartsWithABang writes: When you consider that there are definitely millions of planets in the habitable zones of their stars within our Milky Way galaxy alone, the possibility that there's intelligent life on at least one of them, right now, is tantalizing. But we're in our technological infancy, relatively speaking, having only been broadcasting electromagnetic signatures visible by an alien civilization for around 80 years. Unsurprisingly, we're looking for exactly the types of signals we're capable of sending, but what if that's totally wrongheaded? Based on how technology is evolving and what the Universe is capable of, perhaps we should be looking not at electromagnetic radiation, but neutrino or gravitational wave signals from the distant Universe to search for alien civilizations.
While we have been sending radio transmissions for 80 years, the modularion has changed dramatically, which has negative imolications for finding ET, even if they are using our same frequency bands.
Early on we used FM and AM. Both end up with a strong easy to identify carrier tone. As time has gone one and DSP has become a cheap commodity we moved to more efficient modulations (relative to Shannons's limit). Digital modulations look more noise like and have no carrier as such. GPS is below the noise floor as received due to the energy being so smeared out, and that is from medium earth orbit. Your voice calls are recieved below noise as well in a CDMA system.
So if ET is similarly good at math, they will have moved on to signals that are similarly noise like and may simply be undetectable. There may only be a 100 year or so window to detect Earth, and similar may be true for ET.