Okay, on the face of it, it is kind of cool, but this set of imagery has been floating around for at least a few weeks now, and I haven't seen any discussion of it beyond "Wow, this is really cool." And just when I thought it had gone and died a nice, quiet, dignified death, as memes are supposed to do, it showed up in two of my feeds again today. Here's what I believe is the original source, and today's posters were Kottke.org and Geology Rocks.
I hate bursting bubbles (no I don't), but 1: this will never happen because it can't happen. 2: If it did happen, the distribution of water and land would be the least of our concerns. And 3: If we managed to survive, this would be extremely ephemeral from a geologic perspective, if not from a human perspective. So let's take a look at each of those points.
This will never happen because it can't happen. To stop the earth's rotation over less than eons would take an enormous impact- so enormous that it would probably generate enough heat to melt the solid part of the earth. No oceans, no life, end of story. There are possible ways to slow the earth's rotation, involving other bodies like the moon, but those would never make the earth "stand still."
If it did happen, the distribution of water and land would be the least of our concerns. Let's suppose some technology indistinguishable from magic (see Clarke's third law), wielded by prank-playing aliens, suddenly stopped the earth's rotation. My current velocity with respect to a non-rotating earth is 700 some miles per hour, better than 1000 km/h. Same with the Pacific Ocean, and everything else in my vicinity. All that stuff and me would suddenly be moving at that speed eastward with respect to the now-fixed earth. And in fact everything more than 10-20 km from the poles would likely be thrown into a fatal chaos.
However, let's suppose our mischievous aliens are at least thoughtful enough to place everything on the earth's surface in the same reference frame as their solid locality- a trickier proposition than it may sound like, at first take. We are now the lucky residents of a planet with one day a year: six months of sunshine, and six months of night. Furthermore, as the pictures show, the ocean is massively out of equilibrium with the new surface geoid. Contrary to the description at the Kottke link, the oceans would not "gradually migrate" toward the poles- there's a 13 mile (21 km) difference between the earth's radius at the equator and at the poles. There's going to be a lot of water moving poleward very quickly. Then there's the weather patterns. Consider that the entire equator would be a "mountain range," more than twice as high as the Himalayas. The two hemispheres would essentially be inaccessible from each other. Global atmospheric circulation would effectively be cut into two separate pieces. And on and on... essentially, this would be the worst extinction event in earth's history, and we would certainly be among those to go.
But finally, if we managed to survive, this would be extremely ephemeral from a geologic perspective, if not from a human perspective. The earth's interior is plastic, and the outer core is liquid. I haven't been able to find a number for the largest known post-glacial isostatic adjustment, but a post from an accretionary wedge entry about a year ago gives a figure of 300 m (1000 ft) in the last 10,000 years. The disequilibrium in this case is much greater, and the response rate would likewise be much higher. I don't know enough about the earth's rheology to make anything approaching a calculated estimate for how long it would take to return to isostatic equilibrium (or at least as close as the earth gets, on a year-to-year basis), but I would guesstimate the time range to be on the order of 100 thousand to a million years.
That last number, whatever it is in reality, is the one to keep in mind. There are natural processes that are slowing the earth's rotation rate- the big one being tidal interactions with the moon. The time it will take to tidally lock one face of the earth toward the (already) locked face of the moon is likely more than the time it will take for the sun to burn itself out. To the extent that the earth slows its rotation between now and then, the surface will adjust isostatically to centripetal changes to effective gravity at the poles versus the equator far faster than those changes will happen.
I guess my irritation with this is that I'm seeing it treated as a "science fiction" scenario, but it isn't. It's pure fantasy.
Is This Your Hat?
2 years ago