Gravity’s always been my favorite force. I’ve been cheering from the front lines as it’s consistently exceeded expectations, mapping massive globs of invisible matter, bending light to magnify infant galaxies and glimpse Earth-size planets transiting stars. It twirls space and time around its little finger, gobbles stuff up and then spits it out scrambled, broadcasts news of collapsing stars and colliding black holes to Earth’s very shores—giving physicists grist for yet another Nobel prize.
And yet, it belittles me. Literally, I’m sorry to say. Once a stately enough 5'6", I was recently measured at a relatively puny 5'2".
Gravity puts the “little” in little old lady, and it’s seriously getting me down.
After all, much of the thrill of growing involves defying gravity: those pencil marks on the wall, ever higher; flying off swings and diving boards; on occasion attempting flight off a bed (or, ouch, a roof), held up (we hope) by our superhero bedsheet capes. Bigger kids escape gravity on bikes and skateboards. Some very big kids build expensive toys to race each other into “space,” the better to enjoy the illusion of floating gravity-free for a moment or two.
But there’s no way to really ghost gravity. It permeates everything, easily traveling through walls of lead, reaching through your clothes to pull on your undies. Gravitational waves produced by the explosive beginnings of our universe ripple easily through nearly 14 billion years of space and time to gently lap our shores. Everything is transparent to gravity.
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This superpower comes from the fact that, as Einstein revealed, gravity is space and time, warped by the presence of matter. Mass curves the spacetime around it into valleys and wells into which things appear to “fall”—but in fact follow the straightest paths possible through a topologically complex landscape. As long as you live in space and time, you’d better believe that gravity is out to get you.
Earth-bound bipeds that we are, our minds did not evolve to grasp such concepts as curved four-dimensional spacetime, so no amount of math or analogy is going to make it intuitive. Instead, we rely on everyday experience, looking “down” at our feet and “up” at the sky, even though “down” isn’t a place or even a direction beyond our parochial patch of ground.
Look “down” at your feet. Now imagine someone on the other side of the earth, also looking “down.” You would be looking toward each other! If you both looked “up,” you would be looking in opposite directions.
Now imagine further, as the mathematician Charles L. Dodgson (aka Lewis Carroll) did, that you fell “down” a rabbit hole straight through the center of the earth. At first, gravity would pull you faster and faster toward the middle, until you were zipping along at thousands of miles per hour. At the very center, gravity pulls equally in all directions, effectively canceling to zero. You’d coast along on momentum alone. As you approached the other side, however, gravity would begin to pull you back “down” again, and back and forth you’d go, oscillating endlessly.
That’s where things get interesting: The time it takes to complete a ride through the Earth to the other side is 42 minutes. (Other calculations give slightly different answers, but this is the one Martin Gardner references in his peerless Alice annotations.) If you fell through a hole not through the whole earth, but merely from, say, New York to San Francisco, the trip would also take 42 minutes. The same amount of time!
Given a shorter distance, gravity would never get you going as fast, but you wouldn’t travel as far, and the two effects cancel out. Branson and Bezos aren’t traveling in space so much as traversing the centers of their respective rabbit holes—inhabiting the interval where momentum gets the better of gravity … before gravity grabs them again.
The back and forthing through rabbit holes is a great deal like real life, as an artist friend used to put it. He often talked about the tunnel at the end of the light, which we tend to forget invariably accompanies the light at the ends of tunnels. There’s always the reverse, the inverse, the converse.
Gravity tugs on time as well as space, and memory rabbit holes turn cherished narratives on their heads. One pivotal moment in my personal life story took place in 1969, as I watched Americans land on the moon together with a bunch of friendly Russians, glued to an old TV in the Ukrainian city of Kharkov. Or so I remember. A month ago, I found a journal of that fateful year. Yes, I was indeed in Kharkov on July 17 (local date). No, the Americans and Russians did not celebrate together. “I heard we landed on the moon,” I wrote. “But you wouldn’t know it from local TV, which only broadcasts old news shows.”
Creepier still, my memory of a happy evening downing vodka shots with cute Russian guys was even more perverse. “They said they liked me as a girl,” my journal reported, “but as an American, they’d have no problem killing me.”
There’s an upside to upside down. It encourages flips in perspective, revisitations, necessary correctives. I’ve swung many times between being a writer and an editor, on my own and with a partner, a dog person and a cat person, an East Coaster and left coaster. I hope I’m wiser for it; I know my world is bigger for it.
Besides, we always miss things the first time around. One popular pastime that whizzed right by me was (OK, this is silly) line dancing. These days, twice a week, I strut my stuff with a great group of all-agers in a college parking lot, doing the Korean trot, Cuban cha-cha, country classics. We dance to Elvis. It’s now or never.
Through it all, gravity’s relentlessly at work—crunching my vertebrae, curving my spine, remodeling my middle. The last time I stood in a crowd, standing on my tippy-toes to see, I realized to my horror that my view was blocked by a wall of normal people’s shoulders.
Of course, we don’t “see” the curvature of spacetime, at least not in the usual sense. Still, a copy editor once insisted I insert the term “alleged” before “curved spacetime.” That still amuses me. I mean, we can’t see air either, even though a big enough blow can bring down a building. Moving air (wind), just like gravity, is a kind of pseudo-force, as it depends on relative motion. A car (or boat) moving through still air can stir up quite a brisk breeze. Apparent wind, sailors call it.
But then, we perceive most everything indirectly. We hear the rustling of leaves and deduce wind at work—that is, the presence of moving air. We measure motions of galaxies and deduce the gravitational forces needed to hold clusters together—too much gravitation, it turns out, to be explained by visible stars. Hence “dark” matter—now thought to account for most of the matter in the universe.
Gravity reveals itself to us through what it does to things, myself included. But it’s not a force, like magnetism. It’s merely the landscape of local spacetime. And we know that landscapes matter a lot—not only in physics. If a purportedly “flat” landscape (playing field) tends to keep some folks on top, others at the bottom, you know that not-so-invisible forces are warping things.
Unseen influencers warp our world on a daily basis, mostly ones we’d rather not think about: mutating viruses, fragile power grids, nuclear bombs, plastic oceans. Right beneath our feet, tectonic strains threaten to literally pull the ground out from underneath us—especially if you live in the Pacific Northwest, which sits atop the Cascadia subduction zone, a catastrophe waiting to happen. Then there’s omnipresent AI. Despite red flags raised early by the likes of Bill Gates, Stephen Hawking, and Elon Musk, only now are some people getting alarmed at its power to warp just about everything—now that it’s omnipresent and inevitable, rather like gravity.
My physical self isn’t the only thing in my life that’s shrinking. So is the slice of time I have left, the sliver of knowable stuff I know. A lot of us feel that the number of people we can talk with has shrunken, due to the twin pulls of polarization and orthodoxy. Perhaps that’s due to gravity’s dark side. More than a decade ago, astronomers detected evidence of what is now called “dark energy,” a not-yet-understood “negative pressure” that pulls things apart. It accounts for more of the total energy in the universe than everything gravity can grab put together.
That said, there are advantages to smaller worlds—not just because I can learn the Korean trot on YouTube. I discovered that my neighbor, a year older than me (shorter, too) and an avid mountaineer, also watched the 1969 moon landing from behind the Iron Curtain, though she was in what used to be Yugoslavia while I was in what used to be the USSR. That’s a pretty small world, given how few Americans ventured in those parts during those bad old days.
Quite a few impressive white-haired women live in my neighborhood at the moment. I suggested we form a coven, but no one’s taking me seriously. That’s a shame. Think of the potions we could brew. Mushrooms to make us tall again, like Alice.
You never know: I could concoct a way to defy gravity after all.