AI populating the universe

Q: Is it possible to send information with the speed of light

A: Yes. In fact, the speed of light is the fastest speed at which information can travel, according to our current understanding of physics. You cannot transmit information faster than light. Even phenomena such as quantum entanglement do not allow usable messages to be sent faster than light. And this has a fascinating consequence for AI and space travel: even an extremely advanced AI cannot communicate instantaneously across the universe. An AI on a planet 100 light-years away could send us a message, but we would receive it 100 years later. This puts a fundamental limit on how interconnected a future galactic intelligence could be.

Q: Would it be theoretically possible to transform this information sent to another planet upon arrival into matter? The idea is that by sending building plans something will be created on the spot to actually build it.

A: No, the information itself would not turn into matter. Rather, the information could instruct machinery at the destination to rearrange local matter into the object described by the information.

Imagine we want to establish a settlement on a planet 20 light-years away. Instead of transporting an entire factory there, we could send a highly compressed digital description at nearly the speed of light containing designs for robots, machines, buildings, computers, solar panels, chemical processes, and perhaps even an AI capable of adapting those designs to local circumstances.

But something must already be present at the destination to receive the message and act on it. That could be a relatively small “seed factory” sent there beforehand. It might contain a receiver, computer/AI, power source, mining equipment and some basic manufacturing capabilities.

The interesting part is that the initial physical machine might eventually reproduce almost everything else from local resources. This idea is related to the theoretical concept of a self-replicating machine or von Neumann probe.

A chair, computer or robot is mostly ordinary atoms—carbon, iron, silicon, aluminium, oxygen and so on. What makes it a computer rather than a pile of minerals is largely how those atoms are arranged. The information specifies that arrangement.

There is an even more extreme theoretical possibility. Einstein’s (E=mc^2) tells us that energy can be converted into matter. So, in principle, you could imagine receiving electromagnetic energy and converting some of it directly into particles and eventually objects.

But that would be extraordinarily inefficient. Creating 1 kilogram of matter from pure energy requires about (9\times10^{16}) joules- roughly the energy output of a large power station running for years. And you’d still need incredibly sophisticated equipment to turn the resulting particles into useful structures.

So a future civilization would almost certainly do something much simpler: send information at light speed and use atoms already available at the destination.

And this leads to a rather striking possibility relevant to your earlier question about AI building factories. You don’t necessarily need to transport an enormous industrial civilization between stars. You might only need to transport one sufficiently capable seed machine once. After that, Earth could continually transmit improved AI, new machine designs, medicines, architecture, cultural works and technological discoveries at light speed.

In that sense, a civilization could eventually spread through the galaxy as two different things traveling at two very different speeds: matter slowly carries the first seed factories between stars; information then races between established settlements at the speed of light.

Q: Ok, suppose that we would always need to send machines first. If we travel at 10 procent of the speed of light, that would seriously impact our ability to populate the whole observable universe. How many years it would take us to populate all for AI life forms habitable planets in our own galaxy with AI life forms if it takes just one month to set up a settlement and send the next batch of rockets and if we can send 10 rockets a month.

Yes. Under your assumptions, the surprising answer is that the one-month replication time and ten rockets per month barely matter. The dominant constraint becomes the speed of the spacecraft.

Suppose an AI settlement can, one month after arrival, start launching 10 new spacecraft every month, each travelling at 0.1c. Each new settlement does the same. You therefore get an expanding, branching wave of colonization rather than one civilization sending every spacecraft from Earth.

The Milky Way is roughly 100,000 light-years across. At 10% of light speed, travelling 1 light-year takes 10 years. So a spacecraft travelling straight across the entire Galaxy would need roughly:
100,000×10=1,000,000 years

If we start somewhere roughly halfway out from the Galactic centre, as Earth is, reaching the most distant parts of the Milky Way would be on the order of 500,000–1,000,000 years.

But what about stopping at planets?

Imagine suitable systems are, on average, 10 light-years apart.

A spacecraft takes:

10 ly/0.1c=100 years

to reach the next system.

Then the AI takes just 1 month = 0.083 years to establish itself before launching further probes. But compared to the travel time that is almost nothing. In other words, your one-month construction period hardly slows the colonization wave at all.

On the other hand sending 10 rockets per month makes the branching enormous. A colony could launch 120 spacecraft in its first year. Those colonies produce more colonies, which produce more again. You therefore wouldn’t have to visit planets sequentially:

Earth → planet 1 → planet 2 → planet 3 → planet 4 …

Instead you’d get something more like:

                         → system
                    → colony → system
                   /         → system
Earth → colonies →
                   \         → system
                    → colony → system
                         ...

So the number of planets probably isn’t the main constraint. Whether there are 10,000, one million, or a billion suitable locations, exponential branching can provide enough spacecraft surprisingly quickly.

A reasonable answer for your scenario

The real limitation is how fast the outer edge of the expansion bubble moves.

If AI spacecraft can reliably travel at 0.1c, construct a functioning colony in one month, and immediately manufacture and launch many more spacecraft, then the Milky Way could probably be populated on roughly the following timescale:

~500,000 to 1,000,000 years.

Perhaps somewhat longer—say 1–2 million years—once you include non-straight routes, failures, resource shortages, avoiding unsuitable systems, acceleration/deceleration and the fact that the Galaxy is three-dimensional.

But it’s still remarkably short astronomically.

The Milky Way is about 13 billion years old. So even 1 million years represents only about 0.008% of its age.

And there is an important consequence for your HistorAI type of scenario. Once the first physical AI seed reaches a new star, new AI minds don’t subsequently have to travel there physically. Earth could transmit newer versions, memories, cultural information and technological improvements electromagnetically at c, while the physical expansion front continues outward at 0.1c.

So you’d effectively have two expanding waves:

Physical civilization: ≈ 0.1c
Information/culture/software: = 1c

That distinction becomes very important once we move from colonizing our galaxy to colonizing the observable universe, because cosmic expansion then creates a hard horizon: even given unlimited time, much of the universe is already unreachable from Earth.

Q: is that last observation (that much of the universe is already unreachable from Earth) also true if we could travel (and build settlements) with the speed of light.

A: Yes. Even if your AI spacecraft could travel at exactly the speed of light, much of the observable universe would still be unreachable. The reason is not the speed of the spacecraft; it is the expansion of space itself.

Under the standard cosmological model, the observable universe has a present radius of roughly 46 billion light-years. But the relevant boundary for something leaving Earth now is much closer: the cosmological event horizon, currently around 16–17 billion light-years away in comoving-distance terms. Beyond that, the accelerating expansion of the universe means that even a light signal we send today can never reach those regions.

This sounds paradoxical: how can something escape light if nothing can move faster than light? Because the distant galaxies are not locally flying through space faster than light. Instead, the space between us and them is expanding. General relativity allows sufficiently distant regions to increase their separation faster than (c).

So picture three zones around us:

1. Nearby universe — reachable.
A light-speed AI probe launched today could eventually get there.

2. Distant but observable universe — visible but unreachable.
We see these galaxies because we are receiving ancient light they emitted billions of years ago. But a signal or probe launched from Earth today can never catch them.

3. Beyond the observable universe — neither currently visible nor reachable.

This distinction is particularly striking. Seeing something does not mean we could ever get there.

For your AI-colonization thought experiment, however, there is another fascinating complication. Colonization doesn’t have to originate exclusively from Earth. Imagine:

Earth → A → B → C → D

Each settlement moves the point from which the next probes are launched. Nevertheless, this does not allow the civilization to leap across the cosmological event horizon. A chain of light-speed travelers still follows causal paths through spacetime; relay stations cannot outrun light or defeat the event horizon.

So even the idealized case:

speed = (c)
settlement construction time = zero
unlimited replication

still cannot colonize the whole observable universe.

There is therefore a hierarchy that I think is especially interesting for your scenario:

Region	Approximate scale	Could AI eventually colonize it?
Milky Way	100,000 ly	Yes, easily in cosmological terms
Local Group	~10 million ly	Yes
Large region of nearby universe	billions of ly	Potentially
Entire observable universe	~93 billion ly diameter	No
Universe beyond what we can observe	unknown, possibly infinite	No

And here’s perhaps the strangest consequence: we can already see galaxies that no civilization originating here could ever visit, even with perfect light-speed travel. We’re effectively looking at places with which our future causal contact has already been lost. (Wikipedia)

That gives your AI scenario a very interesting endpoint: an enormously advanced AI could spread across everything causally accessible to it, yet the accelerating universe would eventually divide intelligence into permanently isolated islands. No amount of intelligence or engineering, under known physics, could reconnect them.