As the World Turns (or Not)
by Kim Pederson…….
“We did not notice right away. We couldn’t feel it. We did not sense at first the extra time, bulging from the smooth edge of each day like a tumor blooming beneath skin.” So opens Karen Thompson Walker’s novel The Age of Miracles. The major characters in this fictionocalpyse, Julia and her family, wake up one day and discover the earth has begun to spin a little bit slower and is slowing down more every day. Although it’s described in the book, too, Walker thoughtfully provides a timeline on her website that notes what happens as the world winds down. At first, it’s just the days and nights getting way out of whack with “clock time.” Then, however, people get insomnia, birds die, insects multiply, gravity gets stronger, the days get hotter and the nights colder, people experience gravity sickness, and then…. Sorry, no spoilers here.
My first thought — after of course a moment of mindless panic in which someone in side my head was screaming, “That could never happen, right? Right?” — was that this is pretty weird, not just that the earth could spin more slowly but that we spin in the first place. Que?
Just like, well, clockwork, the earth rotates on its axis from west to east (counterclockwise), completing a rotation every 23 hours, 56 minutes, and 4 seconds give or take. It has done so for roughly four or five billion years. But here’s the really scary thing: the spinning is really slowing down. So what if it’s not quite as fast as in the novel (our days have only gained 1.7 milliseconds in the past 100 years). I’m still going to worry now about every bird (or iguana here in KW for that matter) that drops inexplicably out of the sky (or tree).
But back to my question. Why, indeed, do we spin? Apparently it’s due to something called angular momentum (I should stop here while I still know vaguely that of which I speak). To be more specific (what the heck, I’m going for it), our rotation is “a vestige of the original angular momentum of the cloud of dust, rocks, and gas that coalesced to form the Solar System.”
The science behind all this is mucho bogglesome, to use a word I coined a while back, so I won’t bother you or me with it. Let me just say this about that…er, it. So clouds of stuff in space have a natural tendency to clump together (gravity, another mystery, at work, I guess). The act of clumping somehow imparts a spin that flattens the cloud into a disk. The things within the disk, which have taken on the same spin for reasons beyond me, engage in further clumping, eventually forming a solar system with a spinning sun at the center and planets and moons around that which are…spinning and will continue to spin unless someone or something hits the brakes. (So why, you might ask, am I struggling to explain this when there’s a 51-second video that just shows it to you. I, redfaced now, have no lucid answer.)
Actually, I think I know what is happening. My mind has been going round and round trying to get a grip on this concept. Due to the conservation of angular momentum, rather than slowing down to settle on some kind of answer, it instead spun faster and faster, forcing all my brain cells to clump together into something that resembles a large tapioca pudding, still rotating of course. Like the earth, I expect it will eventually slow and come to rest, allowing me peace and the vestige, at least, of coherent thought. Our planet’s rotation, however, will only decrease another two milliseconds in the next century. If I’m on the same “clock,” I’m in big trouble.
* An animation showing the rotation of the Earth around its own axis. By Wikiscient created from NASA’s “Visible Earth” image (in the public domain). CC BY-SA 3.0.