THE EMPTINESS OF SPACE - Finding Light in the Dark
There are over 200 billion trillion stars floating in the cosmic abyss of our universe. These glowing orbs of fire and gas dot our night sky, shining brightly against a canvas of never-ending black. Each star has its own evolution story, perhaps with its very own solar system of planets and moons, orbiting the center of a foreign galaxy far, far away.
To understand the scale of stars, imagine that you’re on a beach somewhere on Earth, your skin drinking in the sunlight and your eyes grazing the azure blue of the ocean. Bits of sand get caught in between your toes as you walk down to the water, your heels flapping against the sand. You reach down and grab a fistful, feeling the grains rub into your palm as you look out at the expanse of the ocean. In that one handful, you’ve picked up around ten thousand grains of sand. When you multiply that by the number of sandy regions all over the globe, from beaches to deserts to sand dunes to ocean floors, you find that the Earth has seven quintillion grains of sand.
Unbelievably, seven quintillion is a fraction of the total number of stars in the universe—there are over 10,000 times as many stars as there are grains of sand on Earth. It is rather remarkable, then, that the night sky is dark.
Stars are born when darkness collapses on itself. Swirls of gas and dust succumb to gravity, coalescing to form dense stellar cores that form the hearts of stars. As more and more material falls onto the budding core, particles collide, jacking up the temperature until the pre-star, or protostar, is so hot that nuclear fusion ignites in the core, jump-starting its stellar
heartbeat. At this point, the star becomes “alive.”
Stars are huge. Our closest star is the sun, and it could fit nearly 1.3 million Earths inside. But in the cosmic sense of things, our sun is relatively average-size; some stars can be as large as one thousand times the size of the sun.
For the most part, stars are not quiet. They’re violent, turbulent spheres of fire and gas that spew out tremendous cascades of charged particles and radiation. These eruptions, known as solar flares, corona mass ejections, and prominences, disturb the stellar surface, ejecting searing-hot matter millions of degrees Kelvin into the surrounding stellar environment.
One might think 200 billion trillion of these devastatingly bright orbs is a number so astoundingly high that they’d light up the universe. But the universe is dark, cold, and overwhelmingly empty. It’s a lonely place. Despite all the stuff scattered around—the stars that glow; the planets that orbit; comets, asteroids, and whatever else—the universe is mostly vacant. It’s difficult to fathom just how empty space is. The observable universe is about 13.7 billion light-years across. Numbers of this scale are beyond our understanding—perhaps even beyond the human ability to conceptualize scales this size, emptiness this vast.
Thirteen billion light-years of nothingness ceases to truly mean anything until it is measured relative to something else. Those objects dotting the cosmos, though scattered across incomprehensible distances, give meaning to the emptiness stretching between them. Without them, there would be a whole lot of nothingness stretching everywhere, indefinitely. It’s difficult to spot an object billions of miles away. But if you look far and wide enough, you’re bound to find something. Glimmers of stars floating in the cosmic ocean are those beacons on the blackest of nights.