Everywhere we look, we find planets. That was the lesson of yesterday’s historic announcement that a habitable planet orbits Proxima Centauri. And it’s the lesson of every exoplanet survey astronomers have conducted. A few decades ago, it was still possible to wonder whether other stars play host to round, rocky worlds. Not anymore.
But even amidst this multitude of newly discovered planets, we can’t be sure that worlds with rich biospheres like ours are common. It might be fairly easy for nature to manufacture microbes, but complex life seems to need nurturing.
Earth’s history suggests that even under the best of circumstances, it takes time for large, big-brained organisms to evolve. And not every planet can count on a 4-billion-year run of relatively life-friendly conditions—not in a universe where a neighboring star could explode at any time. Some terrestrial worlds will only have a billion years of habitability, or a few hundred million years, and that might not be enough time to ramp up rich, diverse ecosystems with interesting alien creatures.
But what if we could give them a head start?
A new paper by Claudius Gros, a systems theorist at Goethe University in Frankfurt, suggests that future humans could—and more interestingly, should—send “Genesis missions” to planets with limited habitability windows. With our current technical constraints, it’s hard to imagine sending a Noah’s-Ark-style probe housing plants and animals across cosmic distances. But it looks increasingly plausible that we will soon be able to beam small, light-weight spacecraft to distant stars.