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Should SETI Be Looking For Lasers Instead?

Posted by timothy on from the mutant-sharks-come-free dept.

colonist writes "Frank Drake, creator of SETI's famous equation, says the detection of extraterrestrial radio signals won't work, because Earth's own radio signal will only be around for 100 years. More and more of Earth's communications use cable and satellites, with no radio-frequency leakage to space. Instead, we should be looking for intentional signals in the form of high-powered lasers that could 'outshine the sun by a factor of 10,000'. Meanwhile, Paul Davies writes that we should be conducting SETI in our DNA. In turns out that an alien message designed to last millenia should be 'inside a large number of self-replicating, self-repairing microscopic machines programmed to multiply and adapt to changing conditions', otherwise known as living cells. Are we the message?"

2 of 694 comments (clear)

  1. Duh... by Rii · · Score: 0, Redundant

    We're not just a message, we're a giant computer. 42!

  2. Quantum entanglement does not allow FTL comms by slubberdegullion · · Score: 0, Redundant
    Suppose you've got some sort of method to communicate instantly. And suppose you've got a car that can travel at half the speed of light.

    set it up like this. The car is 1 light minute from an observer. It's travelling away from the observer at .5C. It flashes its rear lights.

    from the observer's point of view, it will see the headlights flash 1 minute later. It communicates this instantly to the car, so the car finds out about this at T+1 minute.

    Now from the car's perspective, the light is moving away from it at C, but it's moving forward at .5C, so the light is only getting closer to the observer at .5C. Hence it takes two minutes to reach the observer. At T+1 minute, the light has not reached the observer. So the guy in the car is surprised by the announcement that it has, and sends back an instant communique for confirmation.

    "Confirmation?" asks the observer, "I haven't sent you anything yet!" After all the light has not yet reached the observer, so how could he have sent the communication?

    This is the theoretical problem with instant communication. It breaks the principle of causality. This principle has never been observed to have been broken, and is basic to our understanding of the universe.

    This is why it is unlikely that an instantaneous communication device will ever be invented. Quantum entanglement has been shown not to allow such a device - the entanglement does not transmit any information.