Assume all civilizations hunger for more and more energy, so they will all naturally gravitate toward the most powerful compact power source available: a rotating supermassive black hole, extracting rotational energy from it perhaps by the Penrose process. In this way, they will all become Kardashev Type 3 civilizations.
If this is true, then we would expect that most galaxies to already have their supermassive black holes tapped out. If it is possible to tap such black holes, then we would expect the technique to have already been independently discovered and deployed countless times all across the universe. We should not expect to be so lucky as to be seeing a quasar or active galactic nucleus before some civilization taps it. Both quasars and AGN are thought to be powered by the rotational energy of supermassive black holes.
Then, what could the fact that we do see quasars mean? Here are some possibilities:
- There is no intelligent life in the universe, where "intelligent life" means type 3.
- The universe is still too young too see significant galactic and intergalactic conquests. This is especially true for distant quasars which we observe in from the early universe. Perhaps type 3 civilizations occur extremely rarely, far less than 1 per galaxy, and intergalactic travel, needed for the sum of such civilizations to tap most of the supermassive black holes in the universe, is so slow that that it hasn't happened yet.
- Quasars and AGNs are flukes that are perhaps weird or temporary that most type 3 civilizations don't find it worth the effort to tap when their are plenty of other "normal" supermassive black holes out there. Perhaps they are galaxy mergers.
- Extracting energy from supermassive black holes is always so much more difficult than, say, capturing the energy of all the starlight in a galaxy that it is never worth it for a civilization to do. I suppose this is a dark matter theory: there exist dark galaxies, a tremendous number of them, whose light is being mostly harnessed by a civilization, but they still do (of course) show up when accounting for mass. But I think we would still expect to see their heat output.
- There exists some other power source that all civilizations discover that makes tapping supermassive black holes not worth the effort.
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