Travel to other distant planets is a central conceit for many videogames, from Star Fox to Halo to EVE Online. Being in an alien world gives developers an easy excuse for tweaking the laws of physics for the sake of fun and drama. But just how plausible is the idea of reaching another solar system? Following a Prometheus viewing the Washington Post’s Brad Plummer has done some investigation and, drawing from a recent research paper by former NASA scientist Marc G. Millis, he concludes humans are anywhere between 200 and 500 years away from interstellar travel.
Imagine we merely wanted to launch a small, 11-ton probe that took 75 years to get to our closest star, Alpha Centauri. That’s only about four light-years away. A fairly modest goal. Regardless of what type of propulsion technology is used, that probe would need a jaw-dropping amount of power just to accelerate out to Alpha Centauri and then decelerate once it gets there. (This is based on the kinetic energy of the probe — by Millis’s calculations it would take, at absolute minimum, 8.1 x 10^16 Watts of power.)
And humans don’t exactly have that energy just lying around. For the past three decades, the total energy produced by the world has grown at a modest pace — around 1.9 percent per year. And humans have devoted just a tiny fraction of that to spaceflight. Unless either of those trends changes radically, Millis calculates, we won’t have the energy needed to launch an Alpha Centauri probe until sometime around the year 2463, at the earliest.
Millis’s work also points out an interesting dilemma about improvements in technology after the launch of an interstellar mission potentially leapfrogging the-transit vessel.
No matter when we launch the first interstellar probe, it’ll take a long time to reach its destination. Which means it’s quite plausible that we’ll later invent a newer, faster interstellar probe that gets to the star evensooner, with more modern equipment. Which raises the question of why we even bothered to launch that first probe.