Stephen Hawking famously said that aliens are one of the main risks to human existence. In this map I will try to show all rational ways how aliens could result in human extinction. Paradoxically, even if aliens don’t exist, we may be even in bigger danger.
1.No aliens exist in our past light cone
1a. Great Filter is behind us. So Rare Earth is true. There are natural forces in our universe which are against life on Earth, but we don’t know if they are still active. We strongly underestimate such forces because of anthropic shadow. Such still active forces could be: gamma-ray bursts (and other types of cosmic explosions like magnitars), the instability of Earth’s atmosphere, the frequency of large scale volcanism and asteroid impacts. We may also underestimate the fragility of our environment in its sensitivity to small human influences, like global warming becoming runaway global warming.
1b. Great filter is ahead of us (and it is not UFAI). Katja Grace shows that this is a much more probable solution to the Fermi paradox because of one particular version of the Doomsday argument, SIA. All technological civilizations go extinct before they become interstellar supercivilizations, that is in something like the next century on the scale of Earth’s timeline. This is in accordance with our observation that new technologies create stronger and stronger means of destruction which are available to smaller groups of people, and this process is exponential. So all civilizations terminate themselves before they can create AI, or their AI is unstable and self terminates too (I have explained elsewhere why this could happen ).
2. Aliens still exist in our light cone.
a) They exist in the form of a UFAI explosion wave, which is travelling through space at the speed of light. EY thinks that this will be a natural outcome of evolution of AI. We can’t see the wave by definition, and we can find ourselves only in the regions of the Universe, which it hasn’t yet reached. If we create our own wave of AI, which is capable of conquering a big part of the Galaxy, we may be safe from alien wave of AI. Such a wave could be started very far away but sooner or later it would reach us. Anthropic shadow distorts our calculations about its probability.
b) SETI-attack. Aliens exist very far away from us, so they can’t reach us physically (yet) but are able to send information. Here the risk of a SETI-attack exists, i.e. aliens will send us a description of a computer and a program, which is AI, and this will convert the Earth into another sending outpost. Such messages should dominate between all SETI messages. As we get stronger and stronger radio telescopes and other instruments, we have more and more chances of finding messages from them.
c) Aliens are near (several hundred light years), and know about the Earth, so they have already sent physical space ships (or other weapons) to us, as they have found signs of our technological development and don’t want to have enemies in their neighborhood. They could send near–speed-of-light projectiles or beams of particles on an exact collision course with Earth, but this seems improbable, because if they are so near, why haven’t they didn’t reached Earth yet?
d) Aliens are here. Alien nanobots could be in my room now, and there is no way I could detect them. But sooner or later developing human technologies will be able to find them, which will result in some form of confrontation. If there are aliens here, they could be in “Berserker” mode, i.e. they wait until humanity reaches some unknown threshold and then attack. Aliens may be actively participating in Earth’s progress, like “progressors”, but the main problem is that their understanding of a positive outcome may be not aligned with our own values (like the problem of FAI).
e) Deadly remains and alien zombies. Aliens have suffered some kind of existential catastrophe, and its consequences will affect us. If they created vacuum phase transition during accelerator experiments, it could reach us at the speed of light without warning. If they created self-replicating non sentient nanobots (grey goo), it could travel as interstellar stardust and convert all solid matter in nanobots, so we could encounter such a grey goo wave in space. If they created at least one von Neumann probe, with narrow AI, it still could conquer the Universe and be dangerous to Earthlings. If their AI crashed it could have semi-intelligent remnants with a random and crazy goal system, which roams the Universe. (But they will probably evolve in the colonization wave of von Neumann probes anyway.) If we find their planet or artifacts they still could carry dangerous tech like dormant AI programs, nanobots or bacteria. (Vernor Vinge had this idea as the starting point of the plot in his novel “Fire Upon the Deep”)
f) We could attract the attention of aliens by METI. Sending signals to stars in order to initiate communication we could tell potentially hostile aliens our position in space. Some people advocate for it like Zaitsev, others are strongly opposed. The risks of METI are smaller than SETI in my opinion, as our radiosignals can only reach the nearest hundreds of light years before we create our own strong AI. So we will be able repulse the most plausible ways of space aggression, but using SETI we able to receive signals from much further distances, perhaps as much as one billion light years, if aliens convert their entire home galaxy to a large screen, where they draw a static picture, using individual stars as pixels. They will use vN probes and complex algorithms to draw such picture, and I estimate that it could present messages as large as 1 Gb and will visible by half of the Universe. So SETI is exposed to a much larger part of the Universe (perhaps as much as 10 to the power of 10 more times the number of stars), and also the danger of SETI is immediate, not in a hundred years from now.
g) Space war. During future space exploration humanity may encounter aliens in the Galaxy which are at the same level of development and it may result in classical star wars.
h) They will not help us. They are here or nearby, but have decided not to help us in x-risks prevention, or not to broadcast (if they are far) information about most the important x-risks via SETI and about proven ways of preventing them. So they are not altruistic enough to save us from x-risks.
3. If we are in a simulation, then the owners of the simulations are aliens for us and they could switch the simulation off. Slow switch-off is possible and in some conditions it will be the main observable way of switch-off.
4. False beliefs in aliens may result in incorrect decisions. Ronald Reagan saw something which he thought was a UFO (it was not) and he also had early onset Alzheimer’s, which may be one of the reasons he invested a lot into the creation of SDI, which also provoked a stronger confrontation with the USSR. (BTW, it is only my conjecture, but I use it as illustration how false believes may result in wrong decisions.)
5. Prevention of the x-risks using aliens:
1. Strange strategy. If all rational straightforward strategies to prevent extinction have failed, as implied by one interpretation of the Fermi paradox, we should try a random strategy.
2. Resurrection by aliens. We could preserve some information about humanity hoping that aliens will resurrect us, or they could return us to life using our remains on Earth. Voyagers already have such information, and they and other satellites may have occasional samples of human DNA. Radio signals from Earth also carry a lot of information.
3. Request for help. We could send radio messages with a request for help. (Very skeptical about this, it is only a gesture of despair, if they are not already hiding in the solar system)
4. Get advice via SETI. We could find advice on how to prevent x-risks in alien messages received via SETI.
5. They are ready to save us. Perhaps they are here and will act to save us, if the situation develops into something really bad.
6. We are the risk. We will spread through the universe and colonize other planets, preventing the existence of many alien civilizations, or change their potential and perspectives permanently. So we will be the existential risk for them.
6. We are the risks for future aleins.
In total, there is several significant probability things, mostly connected with Fermi paradox solutions. No matter where is Great filter, we are at risk. If we had passed it, we live in fragile universe, but most probable conclusion is that Great Filter is very soon.
Another important thing is risks of passive SETI, which is most plausible way we could encounter aliens in near–term future.
Also there are important risks that we are in simulation, but that it is created not by our possible ancestors, but by aliens, who may have much less compassion to us (or by UFAI). In the last case the simulation be modeling unpleasant future, including large scale catastrophes and human sufferings.
The pdf is here: