Earlier, we discussed how humanity’s long term survival requires that we thrive. Now we’ll explore what the scale of humanity’s potential might be if we succeed. These thoughts will help us get a sense of just how much is at stake when we consider the dangers of existential risks.
Here we will only focus on the simple question of how many humans may one day live in the future. Separate and worthwhile meditations can focus on other questions such as the quality of experience for future people or the moral imperative of preventing the end of the world.
If we succeed at colonizing other solar systems and eventually other galaxies, the total number of possible human lives in the future is truly staggering.
Let’s dwell for a moment on some numbers. The solar system is large. Our best technology today allows our ships to reach other planets in months to years. Even if you don’t count the Earth, our solar system contains vast resources that we can use. A humble planet like Mars has as much surface area as all the continents of the Earth.
It seems that most stars have planetary systems of their own, so many (even most) could be of immense value to future humans. And there are a lot of them. The Milky Way galaxy, our home galaxy, contains 100-400 billion stars. The main problem is that they are extremely far away. It takes light, the fastest thing in the universe, about four years to reach the closest stars. But that’s just the beginning. Even travelling at the speed of light, it would take tens of thousands of years to reach the far side of the Milky Way. Today’s space ships can’t achieve anything close to even 1% of the speed of light. Someday however, humans may be able to travel at a substantial fraction of the speed of light.
The Local Group of galaxies, of which the Milky Way is one, comprises more than 50 galaxies. The Virgo Supercluster contains more than 100 galaxy groups, of which The Local Group is one. The recently discovered Laniakea Supercluster (in Hawaiian, laniakea means “immeasurable heaven”), of which we are a part, contains roughly 100,000 galaxies. These are some of the parts of the universe which could be inhabited by humans. For a broader discussion of the potential for Earth-originating conscious life in the universe, see Nick Bostrom’s piece Astronomical Waste.
If we can travel to other stars, there may one day be billions of times as many humans alive at one time as there are today. If we can travel beyond our galaxy there may one day be trillions of humans alive at one time for every one of us today. In case the sheer number of living humans wasn’t overwhelming enough, consider the fact that these civilizations could persist for many billions of years.
We live at a time when humanity’s future expansion and survival is not yet certain. We carry a profound responsibility; each of us affects the fate of incredible numbers of future people. The possibility of their existence is in our hands. Their opportunity to live, dream, and be happy depends on whether we succeed today.
Please, dear reader, join us in earnest efforts to succeed.