How Far Beyond Earth Could Humanity Spread?

Added: 2026-05-12

[00:00:03]I think almost everyone has wondered at some point how far we could ever travel into the universe and what will be possible in the future. Looking at the progress of recent years or decades, one might think it's not that long before we've colonized our solar system and perhaps even set out for the stars. And if we look very far into the future, we might think of films like Star Wars and all the other science fiction movies.

[00:00:32]How we travel through the galaxies with warp drive and eventually traverse the entire universe without any problems.

[00:00:40]But reality, as fascinating as the films are, looks somewhat different. Because between what we imagine and what physics actually allows, there's a gap. One we haven't yet bridged. And perhaps we never will. But let's start from the beginning. Where do we really stand today? And how far could we actually ever get if everything goes well?

[00:01:05]Humanity has walked on the moon. That sounds obvious, but it isn't. It was one of the most technically and logistically challenging undertakings in history. And yet, the moon is cosmically speaking right in front of the Earth. Just 384,000 kilometers away. A small leap compared to what the universe has to offer, our far traveling ambassadors in space are the Voyager probes, launched in the 1970s.

[00:01:36]Voyager 1 has now reached interstellar space. It is about 24 billion km from Earth. That sounds unimaginably far. And yet, even at that speed, it would take it about 75,000 years to reach our nearest neighboring star system, Alpha Centuri. And this is where the real problem of it all begins. Before we talk about the stars, it's worth taking a look at what's comparatively close to us. Our solar system is larger than most people realize. A journey to Mars takes between 6 and 9 months, depending on the constellation. And that's with technology we already possess or will possess in a few decades. Jupiter is a completely different scale. With today's spacecraft, it would take around 5 to 6 years. But at the edge of the solar system lies the or cloud, a gigantic shell of icy objects that extends up to two light years from the sun. Even within our own solar system, there are distances that we can hardly bridge with current technology without waiting generations.

[00:02:49]Colonizing the solar system, Mars, Jupiter's moons, perhaps the asteroid belt, is a realistic goal for the next 2 to three centuries. It's difficult, expensive, and dangerous, but it's physically possible.

[00:03:05]The step to the stars, however, is of a completely different order of magnitude.

[00:03:10]Alpha Centauri, our nearest neighboring system, is 4.2 light years away. One light year, nearly 9.5 trillion km. Even at the nearest star, we encounter numbers and distances that are simply unimaginable. And as mentioned, that's just the nearest star. Even if we could build a spaceship that traveled at 1% of the speed of light, which would already be far beyond our current capabilities, it would take us 420 years to reach the next star. And Alpha Centuri is the nearest.

[00:03:47]The Milky Way has a diameter of about 100,000 lightyear. The nearest large galaxy, Andromeda, is 2.5 million lighty years away. The observable universe spans 93 billion lightyear. That's the observable part. It's very likely much, much larger than that. These numbers aren't just large, they're brutal in a way. They show that even with fantastic technology, the universe imposes a limit that no one can overcome. The speed of light.

[00:04:22]And yet, humanity has never accepted a limit without at least testing it. There are propulsion concepts that could one day make interstellar travel conceivable, including laser sails that could accelerate probes to up to 20% of the speed of light. For manned missions, scientists are focusing on nuclear fusion drives, which harness the same power that burns in the sun and could propel spacecraft to a fraction of the speed of light. The theoretical pinnacle is antimatter propulsion which releases the greatest possible amount of energy, but its production remains unimaginably expensive and technically unattainable for the foreseeable future.

[00:05:07]But we don't just want to consider the near future. We're starting with our own human history. If we consider what Albert Einstein discovered over a hundred years ago, it's this. Time is not absolute. It passes more slowly the faster you move. That sounds like science fiction, but it's measured reality. An astronaut traveling at 99% of the speed of light to a star 100 light years away would experience the journey in only about 14 years. For people on Earth, however, 100 years would pass. The spacecraft returns and Earth has aged by generations.

[00:05:49]This time, dilation makes interstellar travel theoretically feasible for the traveler. But the energy problem remains enormous.

[00:05:57]Accelerating a spaceship to 99% of the speed of light would require an amount of energy that all of Earth's current power plants combined could not generate even over thousands of years.

[00:06:11]But as I said, we don't just want to consider the next few decades. Human history shows us something different.

[00:06:18]200 years ago, there were no airplanes.

[00:06:21]100 years ago, there was no nuclear power. 50 years ago, no pocket computers. Progress doesn't follow a straight line. It follows leaps. And the next big leap could change everything for us. But will we ever be able to travel that fast? The honest answer is we don't know. But physics doesn't fundamentally forbid it. And that's crucial. As mentioned, the biggest problem is energy. There's also a second less obvious problem, interstellar dust.

[00:06:54]At 99% of the speed of light, every tiny speck of dust becomes a projectile. A collision with a particle the size of a grain of sand would have the explosive power of a small bomb. A spacecraft would need a shield requiring materials we can't even design today. And then there's radiation. At near the speed of light, cosmic particles become so energized by relativity that they would penetrate any known shielding. The crew would be exposed to a lethal dose of radiation unless we find ways to prevent it that are currently beyond our comprehension.

[00:07:33]In short, the obstacles are real, formidable, but none of them are insurmountable. Imagine it's the year 2800. Humanity has long since perfected nuclear fusion. Antimatter can be produced on an industrial scale and new materials protect spaceships from collisions and radiation like titanium from a raindrop. We have a ship that accelerates us to 99.9% of the speed of light. For the crew on board, time dilation means that a journey to a star 1,000 lighty years away takes only a few decades.

[00:08:10]They could explore the central regions of the Milky Way, map star systems, search for life, all within a single lifetime. In this scenario, the entire Milky Way with its 100,000 light-year diameter would theoretically be explorable, not in one generation, but in many successive expeditions. colonies could be established. An interstellar civilization spread across dozens of star systems would be conceivable.

[00:08:44]And if we think even further, if we assume that humanity not only survives but continues to evolve over millennia, ships could one day travel to the Andromeda galaxy, 2.5 million lighty years away from us. It would no longer be beyond our comprehension.

[00:09:04]Yet, even in this most optimistic scenario, a limit remains that no technology can overcome. The universe is expanding, and vast swades of it are moving away from us faster than light.

[00:09:18]Galaxies that are already billions of light years away will one day disappear forever from our reach. Not because we are too slow, but because the space between us and them is expanding faster than any speed a massive object can ever reach. This means that even in the best case scenario, humanity could only ever explore a tiny fraction of the entire universe. The rest, by far the largest part, is not only inaccessible, it is cosmologically cut off forever.

[00:09:53]One thing I haven't mentioned yet, however, is wormholes. The reason for this is that we don't even know if wormholes exist at all. And if they do, they too have problems in theory. A wormhole is essentially a hypothetical connection between two points in the universe, a kind of tunnel through spaceime itself. Instead of traveling from one star to the next, one would simply skip the space in between. A ship entering a wormhole would emerge on the other side at a completely different location in the universe, possibly millions of light years away in a fraction of a second. The problem is what would be needed to keep a wormhole open. Based on everything we know today, a wormhole without support would collapse immediately, faster than any light signal could travel through it. As I said, a wormhole and traveling through it is all very theoretical.

[00:10:51]So the question of how far humanity could ever travel doesn't have a simple answer. We are currently at the very beginning. The moon, Mars, eventually the stars. Each step will be more difficult, expensive, and complicated than the last. Physics sets limits for us. Yet it also leaves us with some possibilities. Whether fusion drives time dilation or wormholes, all these concepts demonstrate one thing. The universe is not inherently close to us.

[00:11:23]It is simply unimaginably vast. And humanity, considering its history, is remarkably good at eventually making the unimaginable possible. We will probably never travel the entire universe, but theoretically we could go quite far provided that everything I've discussed so far actually becomes a reality.

[00:11:48]I hope you enjoyed the video and I'll see you next time.