One rule of retail marketing maintains that to maximize sales, businesses need to create a sense of urgency. Mega-sale ends soon! Only a few tickets still available! These commercial threats, especially in the age of e-commerce, are almost always a fiction. But they’re effective, an echo of our apocalyptic visions: If we feel a sense of urgency about the human experiment, maybe we’ll actually get to work, whether that’s rushing to save souls before the Rapture or rushing to address climate change.

I try to remind myself that back in the fourth century, Martin of Tours’s eschatological anxiety must have felt as real to him as my current anxiety feels to me. A thousand years ago, floods and plagues were seen as apocalyptic portents, because they were glimpses of a power far beyond our understanding. By the time I was growing up, amid the rise of computers and hydrogen bombs, Y2K and nuclear winter made for better apocalyptic worries. Today, these worries sometimes focus on artificial intelligence run amok, or on a species-crushing pandemic that we have proven ourselves thoroughly unprepared for, but most commonly my worry takes the form of climate anxiety, or eco-anxiety—terms that did not exist a few decades ago but are now widespread phenomena.

Humans are already an ecological catastrophe. In just 250,000 years, our behavior has led to the extinction of many species, and driven many more into steep decline. This is lamentable, and it is also increasingly needless. We probably didn’t know what we were doing thousands of years ago as we hunted some large mammals to extinction. But we know what we’re doing now. We know how to tread more lightly upon the earth. We could choose to use less energy, eat less meat, clear fewer forests. And we choose not to. As a result, for many forms of life, humanity is the apocalypse.

* * *

There are worldviews that embrace cyclic cosmologies—Hindu eschatology, for instance, lays out a series of multibillion-year periods called kalpas during which the world goes through a cycle of formation, maintenance, and then decline. But in linear eschatologies, the end times for humanity are often referred to as “the end of the world,” even though our departure from Earth will very probably not be the end of the world, nor will it be the end of life in the world.

Humans are a threat to our own species and to many others, but the planet will survive us. In fact, it may only take life on Earth a few million years to recover from us. Life has bounced back from far more serious shocks. Two hundred and fifty million years ago, during the Permian extinction, ocean surface waters likely reached 104 degrees Fahrenheit, or 40 degrees Celsius. Ninety-five percent of Earth’s species went extinct, and for five million years afterward, Earth was a “dead zone” with little expansion of life.

Sixty-six million years ago, an asteroid impact caused a dust cloud so huge that darkness may have pervaded Earth for two years, virtually stopping photosynthesis and leading to the extinction of 75 percent of land animals. Measured against these disasters, we’re just not that important. When Earth is done with us, it’ll be like, “Well, that Human Pox wasn’t great, but at least I didn’t get Large Asteroid Syndrome.”

The hard part, evolutionarily, was getting from prokaryotic cells to eukaryotic ones, and then getting from single-celled organisms to multicellular ones. Earth is around 4.5 billion years old, a timescale I simply cannot get my head around. Instead, let’s imagine Earth’s history as a calendar year, with the formation of Earth being January 1, and today being December 31 at 11:59 PM. The first life on Earth emerges around February 25. Photosynthetic organisms first appear in late March. Multicellular life doesn’t appear until August or September. The first dinosaurs like eoraptor show up about 230 million years ago, or December 13 in our calendar year. The meteor impact that heralds the end of the dinosaurs happens around December 26. Homo sapiens aren’t part of the story until December 31 at 11:48 PM.*

Put another way: It took Earth about three billion years to go from single-celled life to multicellular life. It took less than seventy million years to go from Tyrannosaurus rex to humans who can read and write and dig up fossils and approximate the timeline of life and worry about its ending. Unless we somehow manage to eliminate all multicellular life from the planet, Earth won’t have to start all the way over, and it will be okay—at least until the oceans evaporate and the planet gets consumed by the sun.

But we’ll be gone by then, as will our collective and collected memory. I think part of what scares me about the end of humanity is the end of those memories. I believe that if a tree falls in the woods and no one is there to hear it, it does make a sound. But if no one is around to play Billie Holiday records, those songs really won’t make a sound anymore. We’ve caused a lot of suffering, but we’ve also caused much else.

I know the world will survive us—and in some ways it will be more alive. More birdsong. More creatures roaming around. More plants cracking through our pavement, rewilding the planet we terraformed. I imagine coyotes sleeping in the ruins of the homes we built. I imagine our plastic still washing up on beaches hundreds of years after the last of us is gone. I imagine moths, having no artificial lights toward which to fly, turning back to the moon.

There is some comfort for me in knowing that life will go on even when we don’t. But I would argue that when our light goes out, it will be Earth’s greatest tragedy, because while I know humans are prone to grandiosity, I also think we are by far the most interesting thing that ever happened on Earth.

It’s easy to forget how wondrous humans are, how strange and lovely. Through photography and art, each of us has seen things we’ll never see—the surface of Mars, the bioluminescent fish of the deep ocean, a seventeenth-century girl with a pearl earring. Through empathy, we’ve felt things we might never have otherwise felt. Through the rich world of imagination, we’ve seen apocalypses large and small.

We’re the only part of the known universe that knows it’s in a universe. We know we are circling a star that will one day engulf us. We’re the only species that knows it has a temporal range.

* * *

Complex organisms tend to have shorter temporal ranges than simple ones, and humanity faces tremendous challenges. We need to find a way to survive ourselves—to go on in a world where we are powerful enough to warm the entire planet but not powerful enough to stop warming it. We may even have to survive our own obsolescence as technology learns to do more of what we do better than we can do it. But we are better positioned to solve our biggest problems than we were one hundred or one thousand years ago. Humans have more collective brainpower than we’ve ever had, and more resources, and more knowledge collected by our ancestors.

We are also shockingly, stupidly persistent. Early humans probably used many strategies for hunting and fishing, but a common one was persistence hunting. In a persistence hunt, the predator relies on tracking prowess and sheer perseverance. We would follow prey for hours, and each time it would run away from us, we’d follow, and it would run away again, and we’d follow, and it would run away again, until finally the quarry became too exhausted to continue. That’s how for tens of thousands of years we’ve been eating creatures faster and stronger than us.

We. Just. Keep. Going. We spread across seven continents, including one that is entirely too cold for us. We sailed across oceans toward land we couldn’t see and couldn’t have known we would find. One of my favorite words is dogged. I love dogged pursuits, and dogged efforts, and dogged determination. Don’t get me wrong—dogs are indeed very dogged. But they ought to call it humaned. Humaned determination.

For most of my life, I’ve believed we’re in the fourth quarter of human history, and perhaps even the last days of it. But lately, I’ve come to believe that such despair only worsens our already slim chance at long-term survival. We must fight like there is something to fight for, like we are something worth fighting for, because we are. And so I choose to believe that we are not approaching the apocalypse, that the end is not coming, and that we will find a way to survive the coming changes.

“Change,” Octavia Butler wrote, “is the one unavoidable, irresistible, ongoing reality of the universe.” And who am I to say we are done changing? Who am I to say that Butler was wrong when she wrote “The Destiny of Earthseed is to take root among the stars”? These days, I choose to believe that our persistence and our adaptability will allow us to keep changing with the universe for a very, very long time.

So far, at a paltry 250,000 years, it’s hard to give humanity’s temporal range more than one star. But while I initially found my brother’s words distressing, these days I find myself repeating them, and believing them. He was right. He always is. The species will survive this, and much more to come.

And so in hope, and in expectation, I give our temporal range four stars.

HALLEY’S COMET