How many people does it take to colonize another star system?

Popular Mechanics:

Back in 2002, John Moore, an anthropologist at the University of Florida, calculated that a starship could leave Earth with 150 passengers on a 2000-year pilgrimage to another solar system, and upon arrival, the descendants of the original crew could colonize a new world there—as long as everyone was careful not to inbreed along the way.

It was a valiant attempt to solve a thorny question about the future of humans in space. The nearest star systems—such as our nearest neighbor, Proxima Centauri, which is 4.2 light-years from home—are so far that reaching them would require a generational starship. Entire generations of people would be born, live, and die before the ship reached its destination. This brings up the question of how many people you need to send on a hypothetical interstellar mission to sustain sufficient genetic diversity. And a new study sets the bar much higher than Moore’s 150 people.

According to Portland State University anthropologist Cameron Smith, any such starship would have to carry a minimum of 10,000 people to secure the success of the endeavor. And a starting population of 40,000 would be even better, in case a large percentage of the population died during during the journey.

Interesting problem. To me, the answer depends on whether one of them is Jean Luc Picard.



  • Evolved

    The Darwinists in that solar system will point to all the evidence around them showing how life had evolved in that system, while the creationists will point to the colonizers …

  • Moeskido

    Generation ships are always a problem. Something always goes wrong midway through the trip, knowledge is lost, and the inhabitants forget they’re on a ship.

  • Kriztyan

    What about a ship that would keep accelerating continuously throughout the voyage until it reached half way, then it would decelerate until reaching it’s destination. Would this not make the voyage a lot shorter if your were to accelerate next to light speed? Would you not need a lot less people then? I guess the trick would be to device continues impulse in space.

    • Dennis Madrid

      That would drastically cut down on travel time, but the fuel requirements to run a rocket for the entire trip would be astronomical (not to mention it probably would eventually degrade). We’d need a new propulsion technologies that dramatically reduces the amount or type of fuel needed.

  • CapnVan

    I believe the top commenter over there, Kirk Miller, nailed it: It’s not about the number of people on board. It’s the amount of genetic diversity available.

    We already have frozen embryos. We even have frozen eggs. And we’re quite a ways from a generation ship.

    I’m guessing the problem will not be the number of persons aboard.