Level Earth

simonalexander2005 said:

I'm writing a SF novel, and want the following to be as realistic as possible. Scientists here, could you help shed some light on this?:

"If the whole landmass of the earth were levelled off to be completely flat (i.e., at any point on the earth you would be standing at the same distance from the core), what would happen?"

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I assume from reading elsewhere that the earth would become covered in water - but how deep? Would the moon affect? What else would happen? Anyone got any thoughts?

I'd like to clarify that I don't mean the earth formed like this - I mean if someone took a giant plough to the whole earth (for example).[/QUOTE]


There would be no dry land. At least not initially, but there would be plenty of earthquakes as the planet assumed a more stable shape. My guess is that the first dry land would show up in the middle latitudes.

The water would be deepest at the Equator. The water would be hundreds of feet deep. I saw the dpeth calculation somewherere, but I don't remember.

There would be some really, really powerful storms.

The tides would be about what they are.

simonalexander2005 said:

So you think the planet would reform, somehow, and land would reappear? any thoughts on how long that would take?

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I am certain that the Earth would become an oblate sphere, and I am sure that the process would start quickly, but I don't know exactly how long it would take, but the water wouldn't be all that deep. Total water has a volume of about 330,000,000 cubic miles and the total volume is about 260,000,000,000 cubic miles. There are hot spots all around that are blowing out lava, so it wouldn't take long for the mile, or so, of water to have volcanoes sticking out. The earthquakes might take longer, but they would lift more land. If I were a nasty alien conqueror who decided to punish Earth for standing him off so long, then I can imagine ploughing the Earth into a smooth ball, and I can imagine the Earthlings who will live as refugees on a different planet will cheer when the Earth poked its first bit of solid rock out of the ocean.

simonalexander2005 said:

So you think the planet would reform, somehow, and land would reappear? any thoughts on how long that would take?

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Eons.

Well, for the land that emerged to be habitable.

The technological requirements to "plow" a planet flat are incredible. Anyone have stock in Caterpillar?

I can barely conceive of doing such a thing. But if you were to do it, I would imagine you'd want to pulverize the upper portions of the crust so that it would be "easier" to distribute globally. I don't believe anyone would go to the expense of constructing a machine for the task, but would undoubtedly resort to thermo-nuclear devices of some immense yield. Even so, it'd take an very long time, and some high likelihood of disastrous results (to those doing the dastardly deed).

The problem is that the surface rocky crust of Earth isn't a homogenous layer like the rind of an orange, but is riddled with cracks, holes, hard and soft places. The pieces of the crust are in tenuous balance, held in place by gravity, friction, and are rather easily (in geologic terms) displaced. These displacements are due to plate tectonics, volcanism and the tidal forces imparted on the planet by our rather outsized moon.

Consider some well known/documented results of plate tectonics: The sub continent India has moved north, pushing up the Himalayas. That mountain range is young (again in geologic terms) but has been pretty much exactly the way you now see it since before Lucy walked across Africa. A more active geologic feature is the volcanic island chain of Hawaii. Those islands are forming faster than the Himalayas are rising, yet it will be several centuries before the next island emerges above sea level, and longer still before anyone builds a resort there.

In the life spans of humans--or generations of humans who might, by lore, remember the event--it is unlikely the destruction of Earth you propose is possible, let alone any sort of restoration. So I repeat my answer to your question of how long this would take?

Eons.

Continents are geologically different from ocean crust (short version: ocean crust is mainly basalt. Continental crust is mainly granite, which is lighter and floats on top). So unless the leveling changed the basic composition of the crust, continents will eventually re-emerge. But this would happen on a geological timescale, i.e. over many millions (or tens or hundreds of millions) of years. Individual islands will appear much faster than that over hot spots, but still not within human lifespans.

Volcanoes can go from zero to island pretty quickly, and if you're flattening the crust, you're going to be causing more eruptions than usual. So I wouldn't expect it to be that long before an island forms. They might even have formed before the flattening work is finished.

Here's one example:

http://www.guardian.co.uk/world/2009/mar/21/tonga-volcano-island-nuku-alofa

King Neptune said:

I am certain that the Earth would become an oblate sphere, and I am sure that the process would start quickly, but I don't know exactly how long it would take, but the water wouldn't be all that deep.

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The water might be what initially ended up swelling out at the equator, which means the poles might go dry.

The ocean would be just a bit shallower than the oceans are already. About three-quarters of Earth is already underwater.
Average ocean depth is about four kilometers, so in your scenario the ocean would be around three kilometers deep.

There would still be tides, but they would be smaller than they are now. (Ocean basins surrounded by continents produce resonant effects that magnify tides.) Anyway, if you were on a boat in the ocean you certainly wouldn't notice the tides since there would be no reference point for the water level.

There's a minor complication in that what we think of as completely level ground isn't necessarily all the same distance from the Earth's center, due to the Earth's rotation. I take it you mean that the seafloor would be effectively level, with no slope to it; that means it would actually be nearer to the Earth's center at the poles.

I agree that it would take millions of years for new land to form, unless there were some sort of weird aftereffects from whatever process levelled the land in the first place.

jjdebenedictis said:

The water might be what initially ended up swelling out at the equator, which means the poles might go dry.

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That is possible, but I don't believe that the tidal effect is that strong. Hundreds of feet of water would have to move toward the Equator for the poles to dry up. Centrifugal force would move water, but it would be water that circulated toward the Equator then back toward the poles. The currents might be strong.

Let's try and see what happens!