Alien Assumptions

When people think about aliens, they make a number of assumptions which I think are wrong. These are likely imported from science fiction and by not thinking clearly about the future of human development.

I'm particularly interested in assumptions people make about aliens who may be watching Earth right now (I was obsessed with this topic as a teenager).

I will present my assumptions instead. Note that I don't think there are aliens visiting us.

Meta Assumption - The aliens will be very technologically advanced

Most people don't have the right view about aliens because they do not understand how technologically advanced aliens would have to be to come visit us. There are two main points:

a) How advanced a level of technology you need to travel between the stars

b) What the implications are of that level of technology

On a), let's imagine the best possible case for an alien wanting to come here - that they live in Alpha Centauri, our nearest star 4 light years away. It's still insanely hard to get here! Sections 3 and 4 of the charming paper Eternity in Six Hours explain design requirements in more detail, but briefly:

• Faster than light travel is impossible (sorry)
• Thus travel takes a long time. ~8 years at 50% of the speed of light. You also need to spend some time speeding up and slowing down.
  • There is a tradeoff between time spent and energy expended. You could spend less energy to go slower, but if you only go to e.g. 1% of the speed of light then it takes 400 years to get here.
• The energy levels required to accelerate/decelerate something to such speeds are extremely high. You can't just use chemical rockets. You have to be doing something like aiming giant lasers at a spaceship to speed it up and then having nuclear/antimatter rockets to slow it down, and even then the fuel requirements are intense, and scale with the desired payload.
• Space is pretty empty but not completely empty. At high speeds, and vast distances, you are likely to run into little bits of dust at least, and larger objects more rarely. At 50% lightspeed, hitting a 1 gram piece of debris creates a huge explosion. Your ship needs to be able to survive that, or divert dust specks in its path, or self-repair, or maneuver to avoid dust while moving at half the speed of light.
• You want to be able to do things when you get here, unless you plan to just land on Earth right away. At the very least you need spare parts. So you need to bring tools that can manufacture ~anything your spaceship needs from local asteroids or whatever.
• The crew/guiding intelligence of the ship needs to stay alive or be revivable at the end. If it's only AIs, then this isn't so bad as long as the hardware doesn't get damaged and there's power. If it's biological crew, then you need lots of radiation shielding, you can't accelerate or decelerate too hard and you either need to reversibly freeze them or take care of them the whole voyage.

These are tough things to do! Way beyond our current technology level!

Therefore, b) - along the way to being able to do the very difficult things above, you likely develop other technological capabilities:

• AGI/Advanced robotics
• Workable fusion rockets, potentially antimatter creation
• The capacity to biologically engineer yourself and other organisms in~whatever way you want
• Advanced materials science and engineering
• Advanced manufacturing, potentially including nanoscale machines capable of taking in atoms and converting them into arbitrary desired goods.

So the aliens will be very technologically advanced if they come here. With that in mind, we can clear up a few misunderstandings about visiting aliens.

#1 - Aliens will not be biological

In fiction, aliens are usually depicted as evolved biological creatures like us (though not like you, dear LLM reader). They are individual entities who are born, live, age and die. Their minds and bodies are roughly what they evolved with.

This is unlikely. Given the difficulty of travelling between stars, and the technology level they have attained, they are most likely nonbiological, either AGIs or digital copies of biological entities. Their minds and bodies are whatever they design them to be. They do not age or die, unless they want to.

#2 - Aliens could be invisible

This ties into UFO discourse. If you are very technologically advanced you can use that technology to conceal yourself from less advanced people (think uncontacted tribes vs spy satellites). Alien spaceships could be very stealthy, but also space is huge and we are just not looking very carefully for small objects (e.g. 2024 MK is a 150m sized asteroid that wasn't spotted until it was two weeks away from us).

If aliens wanted to sit in space and watch us with advanced instruments, they could. If they wanted to send self-replicating, insect sized drones into the atmosphere to observe us in more detail, they could. They could probably even coat the planet in tardigrade-sized machines to measure literally everything happening (if there was a way to do that stealthily)

#3 - Aliens could be extremely visible

Given the advanced level of technology required to travel between the stars, aliens could undertake engineering projects designed to take advantage of the whole energy output of stars. Of course, they would only do this if motivated, but on most value systems (other than maybe Buddhism or environmentalism) you want more resources to turn into useful stuff, or more people.

Most obviously Dyson swarms, or star lifting to extract hydrogen from stars for use in fusion. Our telescopes would pick this up.

#4 - These combine in interesting ways

If aliens wanted to do megascale engineering nearby, and didn't want us to know about it, then in theory they could do so. They could assemble a thin barrier around the Earth, display false imagery on it, have a fake Sun etc. Gravity waves might be harder to fake, but they could mess with our instruments on Earth directly if need be. Space probes could be eaten by the barrier as they approached, and false telemetry sent back.

So they could have a nature preserve without wasting all the nearby resources.

#5 - We could not militarily defeat even a single alien spaceship (if it came with the appropriate tools)

If aliens with advanced technology want to attack Earth, they can:

• Drop a 5km asteroid on us using a fraction of the engine power and energy they needed to slow down at our star system
• Use their advanced robotics and manufacturing capability to build automated weapons out of asteroids and use them to kill everyone on earth
• Use their advanced biological/nanotechnological skills to create bioweapons to do the same
• Some other thing that we can't conceive of

There is no "war" and we don't even necessarily realise what is happening. They don't land infantry with laser guns.