5 ms·

I just thought "ruled out" makes it sound like they have some criteria for a "alien" signal vs natural.

• coldtea 9y ago
  Well, randomness (entropy of the singal etc) is a good criterion which doesn't require deciphering.
  • dmurray 9y ago
    These "signals" have less entropy than normal, which is what is interesting about them, so we have to come up with additional criteria here.
    • coldtea 9y ago
      Well, simple periodic/repeating signals occur all the time in nature -- so it has to be more advanced than that to consider it an actual message or "intelligence made". Even if it was the Macarena beat it would hardly qualify as such.
      • PoachedSausage 9y ago
        A variation on Clarke's 3rd law is: Any sufficiently advanced technology is indistinguishable from nature. So the origin could be such an advanced intelligence that it looks natural.