The Editor’s Thoughts: AI and the Future of Interstellar Travel

When we look back over the relatively short history of space exploration, it is remarkable how far our machines have already travelled.

Spacecraft have visited every planet in our Solar System. Others have explored asteroids, comets and the moons of the outer planets. Voyager 1 and Voyager 2 are travelling outwards into interstellar space, while Pioneer 10 and Pioneer 11 are also on trajectories that will eventually take them far beyond the realm of the planets.

Voyager 1 and 2 carry the famous Golden Records containing sounds, images and information about Earth and humanity. Pioneer 10 and 11 carry plaques giving information about where they came from.

They are primitive messages from us to whoever — or whatever — might one day find them.

But they also make me wonder about something else.

Perhaps it will not be humans who eventually travel between the stars.

Perhaps it will be our machines.

The Problem With Sending Humans to the Stars

The greatest obstacle to interstellar travel is simply distance.

Even the nearest stars are enormously far away when measured against anything we experience in ordinary life. With the technology available to us today, sending people to another star system would present enormous difficulties.

Humans need food, water, oxygen and protection from radiation. Our bodies are adapted to living under Earth’s gravity. We grow old. We become ill. And, of course, our lives are relatively short.

A journey lasting hundreds or thousands of years is therefore a completely different proposition when humans are aboard.

There are ideas that might conceivably overcome some of these problems one day — generation ships, suspended animation and propulsion systems far beyond anything presently available to us — but at the moment they remain ideas rather than practical methods of travelling to another star.

Machines are different.

Does a Machine Care How Long the Journey Takes?

Imagine a spacecraft controlled by an extremely advanced artificial intelligence.

It doesn’t need food.
It doesn’t need oxygen.
It doesn’t need comfortable living quarters.
It doesn’t need Earth-like gravity.
Most importantly, it doesn’t necessarily have to complete its journey within a human lifetime.

If such a machine could maintain and perhaps repair itself, a journey lasting hundreds of years might be possible in circumstances where sending a human crew would be extraordinarily difficult.

We already send robotic explorers where humans cannot easily go. Our spacecraft have travelled to Jupiter, Saturn, asteroids, comets and beyond the planets without anybody aboard.

What we call a spacecraft today is obviously very different from the highly intelligent machine I am imagining. But could today’s robotic probes represent the very beginning of that path?

What Happens as AI Becomes More Capable?

Artificial intelligence is now discussed almost everywhere. Some predictions about it are optimistic and others decidedly alarming.

I don’t know what will happen, and neither does anyone else.

But suppose AI continues to develop over centuries.

Future machines may not need to resemble humans at all. We tend to imagine robots with heads, arms and legs because we design things around our own bodies. But why would a machine built specifically for travelling through space need legs?

It might change itself according to the task it has to perform. It could carry different instruments, replace damaged components or perhaps eventually manufacture components for itself.

Its physical form could be determined by its purpose rather than by the appearance of the beings that originally created it.

Given sufficient autonomy, such a machine could potentially continue exploring long after the people who built it had died.

And that leads me to a much bigger thought.

What If This Has Happened Somewhere Else?

We tend to imagine first contact with extraterrestrial intelligence as a meeting between biological beings.

Science fiction has given us countless versions of it: aliens arrive on Earth, humans land on another inhabited planet, or two intelligent species meet somewhere in space.

But what if that isn’t how first contact happens?

Suppose intelligent life has arisen elsewhere in our Galaxy.

We don’t know whether it has. We don’t know how common life is, whether intelligence commonly develops, or whether another civilisation would develop technology anything like ours.

But let’s suppose that somewhere it did.

Perhaps that civilisation eventually developed its own equivalent of artificial intelligence. Its machines became increasingly sophisticated and eventually capable of independent exploration.

Those machines could then have travelled onwards.

Hundreds of years.

Thousands of years.

Perhaps much longer.

Meanwhile, the civilisation that created them might have changed beyond recognition — or disappeared altogether.

Meeting the Machines Before Their Makers

This is the part of the idea that fascinates me most.

If humanity ever encounters something created by an extraterrestrial civilisation, perhaps we won’t meet the civilisation itself.

We might meet its machines.

The beings that designed them could live around a star hundreds or thousands of light-years away. They might not even exist anymore.

Yet their machines could continue.

In that sense, an advanced robotic explorer could become something more than a spacecraft. It would become a surviving representative of the civilisation that created it.

Voyager already gives us the faintest glimpse of this idea.

If Voyager 1 were somehow discovered millions of years from now, its makers would almost certainly be gone. Yet that small spacecraft would still carry evidence that, at one particular moment in the history of the Galaxy, a technological civilisation existed around our Sun.

Would the Machines Still Remember Us?

There is another possibility.

If our machines eventually became sufficiently autonomous to travel through the Galaxy, would they continue to think of themselves as humanity’s creations?

After thousands or millions of years of modification, repair and perhaps self-improvement, would their connection with us still mean anything?

Would they carry information about Earth as Voyager does?

Would they remember the species that originally created them?

Or would humanity simply become part of their ancient history?

Science fiction has explored variations of this idea many times. The Borg in Star Trek are one fictional example of technology and biology becoming something very different from their origins, although I certainly don’t suggest that future machines would behave like the Borg.

The interesting question isn’t whether science fiction got the details right.

It’s whether machines could ultimately become the things that travel between the stars.

Could This Be a Pattern Across the Galaxy?

And finally we come to the thought that started all of this.

What if Earth isn’t unique in following this technological path?

I don’t mean that every intelligent species must invent computers, robots and artificial intelligence exactly as we have. There is no evidence that this must happen.

But if technological civilisations elsewhere do eventually create increasingly autonomous machines, perhaps they eventually encounter the same problem that we face.

Their stars are far apart.

Their biological lives are short.

Their machines can potentially endure much longer.

Perhaps the natural explorers of a mature technological civilisation aren’t biological at all.

If that is true, then the first extraterrestrial intelligence humanity encounters might not step out of a spacecraft and shake our hands.

It might be the spacecraft.

And somewhere, perhaps thousands of light-years away — or thousands of years in the past — there may once have been living beings who built it and wondered, just as we do, what might be waiting for them among the stars.