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Cellular Phone Spectra and Earth's SETI Invisibility

Posted by timothy on from the and-I-need-all-the-tin-foil-you've-got dept.

astrobio writes: "How long will the Earth's technology be detectable to other worlds? From an article today by the Chairman of the SETI Institute: 'Not long, with shared transmission spectra. To transmit ever-increasing amounts of information, portions of the spectrum must be shared. This is only possible if signal strengths are reduced so that transmissions on the same frequency do not interfere with one another. The textbook example of this paradigm is the cellular phone system. This signal reduction means we are well on our way to becoming invisible.'"

1 of 51 comments (clear)

  1. Our signals may not be visible by PhysicsGenius · · Score: 0, Troll
    New research indicates that the assumption that a signal sufficient strength can travel arbitrarily far. Einstein himself showed nearly a century ago that spacetime is bent back on itself in the presence of gravitational force. For an object the size of a planet the effect is minor (except for the inhabitants, ha ha) but even something as relatively puny as our sun can deflect a beam of light measurably.

    The point of this is that a signal may only propagate outwards until the total mass behind it exceeds a critical value (the location of this is called the "event horizon" in an analogy to black holes). At that point its deflection will equal more than 90 degrees...i.e. it will not go any farther from its point of origin.

    This new research is controversial but nobody's found any rebuttal to it so it will probably become the convential wisdom in the next few years. Sorry, alien-finding dudes.