How the vastness of space can rob us of meaning
“Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is…” wrote Douglas Adams in The Hitchhiker’s Guide to the Galaxy. He wasn’t exaggerating by much. The observable universe—the portion of the cosmos we can theoretically see—is immense on a level that defies human intuition. Modern astrophysics tells us it spans about 93–94 billion light years in diameter, filled with around 2 trillion galaxies give or take a few hundred billion. That’s an estimated 10²³ stars (a 200 sextillion or “200 billion trillion” shining suns) scattered across space. These numbers are so far outside ordinary experience that our minds wobble trying to grasp them.
We evolved to deal with the scale of savannahs and storms, not gigaparsecs of expanding spacetime. It’s no wonder the human brain struggles to comprehend a universe of this magnitude—a place where even light, the fastest thing in existence, isn’t fast enough to get from one end to the other. In this article, we’ll explore what cutting-edge cosmology says about the vastness and structure of the observable universe, why some light will always remain beyond our reach, how pop culture tries (and often fails) to depict such enormity, and what it all means for us thinking specks trying to make sense of it.
Let’s start with the raw numbers that make astronomers sound like they’re just making stuff up. The observable universe—essentially, the spherical “bubble” around us delineated by the farthest light that has had time to reach Earth since the Big Bang—is about 93 billion light years across. Yes, billion with a “B.”
For contrast, our home, the Milky Way galaxy is “only” about 100,000 light years wide, and our entire solar system could fit in a single pixel on a map of the Milky Way. Now consider that the Milky Way is just one galaxy among roughly 2 trillion others in the observable universe. If each galaxy has on the order of 100 billion stars (like ours does), we end up with an estimated 10²² to 10²⁴ stars in total. That’s more stars than there are grains of sand on all Earth’s beaches—by a wide margin. Astronomers figure there are about 9,000 stars for each grain of sand on Earth.
It’s the kind of quantity that turns your brain into applesauce. Humans are pretty good at intuitively sensing numbers up to maybe a few dozen; after that, we rely on metaphors and comparisons. For the observable universe, even our metaphors throw up their hands: “billions of trillions,” “like sand grains,” “like all the cups of water in the oceans”—none of it truly conveys the reality. The scale is, as Adams said, mind-boggling.
And it’s not just the amount of stuff out there—it’s the distances and the structure. Those trillions of galaxies are arranged in a vast cosmic web, filaments and clusters separated by enormous voids. The large-scale structure of the cosmos has been likened to a sponge or a honeycomb, with superclusters of galaxies forming the “walls” surrounding empty bubbles. The farthest light we can currently see is the cosmic microwave background radiation, a faint afterglow of the Big Bang, which comes from about 46.5 billion light years away in every direction.
An Expanding Horizon – and Light We’ll Never See
One of the most counterintuitive discoveries in 20th-century science is that space itself is expanding. Ever since Edwin Hubble observed in 1929 that distant galaxies are receding from us—with farther galaxies receding faster—we’ve understood that the universe is stretching in all directions.
Every large volume of space is like a chunk of rising raisin bread dough: as the dough expands, the raisins (galaxies) all get farther apart without any raisin actively moving on its own. This cosmic expansion means that the distances between galaxy clusters grow over time, and light traveling through space gets stretched (redshifted) en route.
Crucially, expansion is not limited by the speed of light. Only things moving through space are bound by the universal speed limit of light (~300,000 km/s). But space itself can expand at any rate. At extreme distances, galaxies are being carried away so fast by the expansion of the universe that from our perspective their recession velocity exceeds the speed of light. This doesn’t violate relativity—no galaxy is locally breaking the light-speed limit; rather, it’s the space between us that’s swelling.
This creates a concept known as the cosmic event horizon—a maximum range beyond which light emitted today will never reach us in the future because the space in between is expanding too quickly. Right now, calculations indicate that galaxies beyond roughly 16 billion light years are receding so fast that light they emit today will never make it to Earth, no matter how long we wait.
It’s a bit heartbreaking in a way: there are galaxies out there that existed, perhaps even still exist, which we will never get to see, not even with the most powerful future telescope, simply because of the relentless expansion of space. The universe is hiding some of its light from us forever, shroudingdistant galaxies beyond a horizon of no return. We live in a kind of “visible bubble” that will only ever show us a portion of all that exists.
Cosmic Dread
When faced with the incomprehensible, we often turn to art, humor, and storytelling to convey a sense of it. The vastness of space is no exception— our culture is full of attempts to dramatize or poke fun at how huge the universe is and how, comparably, tiny we are.
We already began with one of the most famous: Douglas Adams’ brilliantly comedic line about space being “mind-bogglingly big.” Adams also invented the fictional Total Perspective Vortex, a machine specifically designed to show a person the entire infinity of creation and their infinitesimal place within it—an experience so soul-crushing it was used as a form of torture in his stories.
Carl Sagan’s Cosmos TV series (1980) did an elegant job using visual metaphors—like the “cosmic calendar” compressing all of cosmic history into one year. More recently, Interstellar (2014) touched on cosmic distances by depicting relativistic time dilation near a black hole. And then there’s Men in Black, which imagines our entire universe as a marble in an alien’s game.
Finding Meaning in Smallness
The scientific implications of an ever-expanding universe are significant. Future telescopes might see the first stars and galaxies that formed, pushing our visible frontier slightly. But they cannot break the barrier of the cosmic horizon; no matter how good our instruments, we are bounded by light and time.
Philosophically, coming to grips with our extreme smallness in the context of space and time can be challenging. Some people initially react with a sort of existential dread: if we’re so tiny and the universe so uncaringly huge, do our lives have any meaning? But many scientists and thinkers have turned this around into a more uplifting perspective.
We can, again, look to Carl Sagan who framed it beautifully in his reflection on the Pale Blue Dot—our home, Earth, is an insignificant speck in the cosmos, yet it’s also the only known oasis of life. Our smallness is not a reason for despair but for wonder. If anything, knowing the universe is incomprehensibly vast can make our everyday anxieties seem trivial.
Rather than feeling meaningless, we can be grateful that we exist at all. We are, after all, the only known part of the universe that knows itself. However fleeting our existence is relative to the age of the stars, however small our planet is beneath the sweep of galaxies, we have the capacity to observe, question, and marvel. And in the end, that makes us significant in a way that size alone never could.