What would happen if?

[DUlover2909]

What if the earth was all water? Water all the way to the core with the same mass as the present earth and no other minerals or elements? Also, assume it would be the same distance from the sun and disregard the moon. Would the center freeze? Would there be icecaps?

I've always wondered if there is a model for determining these sorts of things and what would change if one started with a spehere of any particular element or compound. Does anyone know? Does it take a computer simulator to figure it out?

[SteinbachMB]

1. We'd be dead

or would never have been born: or all wet.

[Igel]

2. No other takers?

I'll try.

I can't comment on the overall temperature. It might depend on the starting conditions--does it start off warm or a block of ice at -273 Celsius? If liquid, I think we'd have an atmosphere--over time enough H2O would dissociate and the hydrogen leak into space to provide oxygen. No other elements? At all? So we'd have O2 and H2O making up the atmosphere. It might stay warm enough to make the glob warm enough to be liquid. I don't think it would lose that much oxygen to space.

But the "no other elements" stipulation would soon cease to be valid. Tons of stuff enters the Earth's atmosphere every day. It might not provide enough mass for much, but it should provide enough trace elements for life, eventually, if there are no other problems. The atmosphere would be thinner so more rock would hit the surface (and create a very nice splash). They'd eventually create a core. Carbon in the meteors could provide trace amounts of CO2. Would it have thunderstorms? Um ... I doubt it. No reason for any one area to have a greater charge than another. In the absence of electrical discharges and heat from magma, it would be left to high energy radiation from the sun and space, as well as space debris, to provide any organic compounds. Would that be enough for life? (On edit: Come to think of it, there might be hurricanes, rather massive ones, if the atmosphere's thick enough.)

If it were liquid, I think convection would keep ice caps from forming.


Might be a fun exercise (for someone else) to actually set up a model using what's known about solar activity over the last 4.8 billion years and see how it plays out. Devil's in the details, and all sorts of details might effect the final state.

[hunter]

3. Without calculating, I'd guess it'd be a big ball of ice.

It's the decay of radioactive elements that keeps our volcanos going. No radioactive elements, no heat. Any heat that was there by the formation of the water world would circulate to the surface quickly above the denser forms of water ice towards the center -- at high enough pressures there are forms of water ice that are denser than water.

http://en.wikipedia.org/wiki/Ice#Phases_of_ice

It shouldn't be too complicated to calculate the pressure toward the center to see what phases of water ice might form.

[DUlover2909]

4. thanks for the thoughtful responses.

:-)

[Ready4Change]

5. My guesses - thought train

It's hard to imagine how it could come into existence in the first place. Our solar system developed from coalescing masses of rock, dust and other junk. To get there I'll assume the Earth started as a chunk of ice from some other system that got caught by our sun.

"Would the center freeze? Would there be icecaps?"
"Water all the way to the core with the same mass as the present earth"

I'd say ice caps at the poles, but liquid between on the surface due to solar radiation. What the core is like it tough. Our core is hot partially due to residual heat from the planets formation, partially (it is thought) due to radiactive decay, and partially due to compression and internal frictions.

Does water compress enough to rise in temperature? I don't know. I'm guessing, at the extremes created by an Earth sized mass, that it would. On the other hand, solar radiation would only penetrate so far. I'm guessing that there would be an icy core, surrounded by an ocean many miles deep. Lots of vertical currents, as iceberg sized chunks break from the core and rise, cool currents from the poles sink, and day and night sides of the planets rotate about. It would be like a big slushy machine, churning away.

"and no other minerals or elements?"

I'd think that would inhibit the initial formation of life, as many needed elements, when they eventually fell to Earth, would sink and become imbedded in the icy core. Eventually there would be a small, rocky, metallic core surrounded by a layer of ice, still insulating such elements form creating life.

We're finding there are lots of basic organic elements in space. Do any of these have a density lighter than water? If so, they could be deposited and form a layer on the surface, which could eventually give rise to life? I'm guessing so, but that it would take longer than the conditions that existing on our real Earth.

"Also, assume it would be the same distance from the sun and disregard the moon."

The moon has actually stripped away a lot of our atmosphere. Without it we'd be much more like venus. I'm guessing sunlight and vacuum acting on ice would cause it to sublimate, and split some water into little H's and O's. Many H's, being light, would escape, or join with trace elements falling to earth, and eventually we'd have an extremely oxygen rich, deeply clouded atmosphere.

Hmmm, that would be highly reflective. I just changed by guess from a big slushy to a big iceball. That keeps falling chunks of debris closer to the surface, but in colder temps. Yet, we're close enough to get a LOT of solar radiation.

So, I'm guessing we'd have a very deep, dense, completely clouded, oxygen rich atmosphere around a dirty iceball, perhaps with a thin coating of slime life forms here and there.

"I've always wondered if there is a model for determining these sorts of things and what would change if one started with a spehere of any particular element or compound. Does anyone know? Does it take a computer simulator to figure it out?"

Somewhere someone likely has such things, and they likely disprove all my guesses.

But it's fun to try!

[Name removed]

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[Tesha]

7. Kevin Costner would be a much-more-acclaimed actor than he presently is.

http://en.wikipedia.org/wiki/Waterworld

http://en.wikipedia.org/wiki/Kevin_Costner

[HiFructosePronSyrup]

8. Pure water? Yes, it'd freeze.

The earth has a molten interior now because of radioactive decay. Absent that, yeah, I'd think it'd freeze. Polar caps at the poles, at least during winter, I'm guessing liquid water in the tropics.

[Tesha]

9. But it wouldn't freeze as Ice-I

http://www.uwgb.edu/dutchs/petrolgy/Ice%20Structure.HTM

[Trajan]

10. Where is the Ice-Nine ?

See the Cat ? .... See the Cradle ????

[Tesha]

11. Sorry, no damned cat, no damned cradle. ;-) (NT)