We know with certainty that our sun will eventually expand and consume this planet. That is not a theory. It is a timetable we have not yet met. Before that moment, we must be somewhere else — and that requires a level of civilizational advancement we have not yet achieved. What we do not know is what comes before it. At this moment, some event may already be in motion that will make this world, or this solar system, or this galaxy inhospitable to us — an object on a collision course, a stellar event we have not detected, something we have not yet conceived of as a threat. We cannot know what it is or when it will arrive. What we can know is that our only viable response to an unknown threat on an unknown timeline is to keep advancing — in science, in capability, in the reach of our species — so that when that event arrives, we are not helpless before it. And when that hurdle is cleared, the next is also certain. This is not a race we win. It is a race we must never stop running. We are not standing still. Things are moving fast — faster than any previous generation has experienced. But the scope of what we are racing against is so vast that fast may not be fast enough. That gap between the speed of our progress and the scale of what we face is what keeps me here. That, and something simpler: I could not live with the idea that I might have changed something and just didn't bother.