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The Neumann probe idea has one flaw: it's assumed the probes will propagate and spread largely unimpeded. However, any interstellar civilization which encounter
by openasocket 10y ago
The Neumann probe idea has one flaw: it's assumed the probes will propagate and spread largely unimpeded. However, any interstellar civilization which encounters a probe is going to capture it and analyze/destroy it. They would not allow it to float though their territory and replicate. At the least they will intercept any that enter their territory; if the civilization gets annoyed they may embark on a campaign to wipe out as many as they can. Which leads us to two possible explanations, assuming a civilization has already sent out probes:
1. The civilization was bordered on all sides by other interstellar civilizations, which stopped the probes from spreading.
2. Our civilization is bordered on all sides by other interstellar civilizations (or perhaps is in a remote backwater of a civilization, like uncontacted indigenous tribes in the Amazon), which stopped the probes from reaching us.
There's even a third, somewhat stranger and less likely option:
3. Some civilization is profoundly annoyed by Neumann probes, and has devoted themselves to destroying them everywhere. They made their own stealthy fighter probes, which wander deep space destroying any probes they may find. Perhaps they are keyed in to one specific model of probe that annoyed them, or perhaps will target any unmanned spacecraft with certain properties.
- agentgt 10y ago4. I would add an even stranger 4th option in that given the probes are sufficient intelligence they perhaps "evolve" into an uncontrolled state. That could mean as simply as getting stuck like in local minimum in the hill climbing algorithm or something extremely complex as a probe like civilization (aka Star Trek 1 but in this case no longer cares about space exploration).
- mcbits 10y ago5. The von Neumann probes are microscopic and densely packed with a chemical structure encoding the information needed to reproduce in a variety of environments. Occasionally some of them mutate and get stuck in a planet's gravitational well, where they keep reproducing and mutating into who-knows-what. The urge to explore the cosmos is never completely lost, and eventually they reach a state where it's possible to continue the mission.
- mrfusion 10y agoI'm not convinced such a probe can be much smaller than a large global civilization. What makes us think they can be compact? Just magical nano technology?
- openasocket 10y agoYou mean a probe capable of self-replication? They can absolutely be quite small. As a motivating example, a bacteria is capable of self-replication despite being microscopically small! Human beings are capable of self replication, along with being able to construct anything they want out of raw materials.
- mrfusion 10y agoCan bacteria leave their planet and escape the pull of their star? I think you missed the pint of my comment. I mean a probe that can replicate itself and send its offspring to other solar systems. But even replication alone would be very difficult on a planet with no prior life. a bacteria can't just harvest light, rocks and dirt to reproduce.