The human future in the cosmos could be all but limitless, if we don’t destroy ourselves first. The same would be true of intelligent aliens elsewhere in the Universe, assuming they exist: how far they travel depends strongly on how long they survive as a species. That survival variable, which the US astronomer Frank Drake incorporated into his famous equation on the likelihood of technological civilisations beyond Earth, is unknowable at present because we are the only such civilisation yet identified. Let’s be optimistic and assume that humans are persistent, working their way through the manifest problems of mastering their tools – or at least mastering them long enough to plant colonies off-world, so that our destruction in one place doesn’t mean the death of the species.
There’s a lot of real estate to consider across the star lanes of the Milky Way. Take a sphere 100 light-years in radius, with the Earth at its centre: within it, there exist about 14,000 stars. Beyond that, we don’t know the frequency of habitable planets in our entire home galaxy of 200 billion stars, but current indications are that they’re plentiful, with some estimates running into the tens of billions. If we can begin planting even a few colonies elsewhere in our solar system, and eventually on planets around other suns, our species becomes ferociously hard to eliminate. Kill off one branch and the others persist: learning (we hope) from the sad experience of their forebears; trying new social experiments; pushing technologies to ever higher levels of sophistication; finding out about life elsewhere; and continuing to explore.
Putting the cart before the horse. The more we take care of Earth, the less likely we will be forced to leave it. To read more, click here.