What if a planet consisted almost entirely of water?

[Baby Astronaut]

Not just on the surface, but down to its core.

 

Let's say eons ago there happened to be a great deal of water in one area of a star system, water that via gravity collected and eventually formed into a planet. Along with gases for atmosphere.

 

There would be enough dissolved minerals for life to develop into living bodies, complex functions, and interconnected ecosystems. Any solid formations would be life-based -- such as coral lattices or floating star trees (named for its wooded shape) -- or disintegrated meteors from the occasional cosmic impact. There may even be flying creatures above water, using large patchworks of star trees as a rest stop.

 

It's a planet with no real land, or even a rocky core.

 

Any scientific problems with this? Can such a planet exist?

 

What happens physically to water at the core, under such pressures?

 

To ward off cosmic radiation, let's assume that a pair of metallic moons orbits it, each at geo-opposite positions and a magnetic field that envelops the planet as the fields merge or overlap.

[ecoli]

My hunch is that there wouldn't be enough mass at the core to hold it together... ?

[Iota]

Are we assuming it's in space with nothing else around it or nearby it? E.g. a Sun, rock debris, other planets...

[Moontanman]

Not just on the surface, but down to its core.

 

Let's say eons ago there happened to be a great deal of water in one area of a star system, water that via gravity collected and eventually formed into a planet. Along with gases for atmosphere.

 

There would be enough dissolved minerals for life to develop into living bodies, complex functions, and interconnected ecosystems. Any solid formations would be life-based -- such as coral lattices or floating star trees (named for its wooded shape) -- or disintegrated meteors from the occasional cosmic impact. There may even be flying creatures above water, using large patchworks of star trees as a rest stop.

 

It's a planet with no real land, or even a rocky core.

 

Any scientific problems with this? Can such a planet exist?

 

What happens physically to water at the core, under such pressures?

 

To ward off cosmic radiation, let's assume that a pair of metallic moons orbits it, each at geo-opposite positions and a magnetic field that envelops the planet as the fields merge or overlap.

 

 

There would almost certainly have to be a small rock and metal core but it could be surrounded by a huge envelope of water in fact there are two planets in our solar system that are basically made this way... Neptune and Uranus are not gas giants like Jupiter and Saturn they are ice giants and this is what you are describing.

 

If the Earth was covered by many miles of water at some depth the water turns to ice, not the cold ice we are familiar with but ice none the less. Neptune is made mostly of various ices kept solid under pressure, the surface of Neptune is not cold and could be covered by a layer of liquid water mixed with ammonia and various hydro-carbons like methane but not many miles down these liquids would turn to high pressure ices.

 

Some of the new planets discovered recently may very well be such mini Neptunes and such a planet close enough to it's star could have vast planet wide oceans covering hundreds of not thousands of miles of ice over a rocky metallic core. In the case of Neptune and Uranus the atmosphere is probably pressure enough to cause water to be ice at the surface but a smaller planet with a less extensive atmosphere might have liquid water at the surface.

 

As for life... I'm not sure such a planet would have much in the way of the ingredients for life, most of the elements necessary would be locked away under many miles of ice. Life on Earth depends at least to some extent on the recycling of chemicals through the Earths mantle through volcanoes, I'm not sure if such processes would work on an ice giant...

[akh]

As others have pointed out, there would almost certainly be some rocky and metal component. To our knowledge, these components are intrinsic to the formation of all planets in the solar systems. I also do not think there is anyway that a solar system could form with just water as the sole gas molecule.

 

I am not sure, but I think a water core could induce a magnetic field, but possibly a weak one. So maybe there is not a need for special moons.

 

If the Earth was covered by many miles of water at some depth the water turns to ice, not the cold ice we are familiar with but ice none the less. Neptune is made mostly of various ices kept solid under pressure, the surface of Neptune is not cold and could be covered by a layer of liquid water mixed with ammonia and various hydro-carbons like methane but not many miles down these liquids would turn to high pressure ices.

 

Ahh but water ice is not your typical solid. Unlike other "ices" water expands when it freezes. So to a point, increased pressure actually lowers the freezing point of water. The phase plot for water is pretty interesting stuff. http://en.wikipedia.org/wiki/Ice. I guess its a question of how much pressure at what temperature

 

 

 

As for life... I'm not sure such a planet would have much in the way of the ingredients for life, most of the elements necessary would be locked away under many miles of ice. Life on Earth depends at least to some extent on the recycling of chemicals through the Earths mantle through volcanoes, I'm not sure if such processes would work on an ice giant...

 

I am not sure this would be an issue. I think there would still be thermal convections that could cycle the necessary elements.

Edited August 17, 2012 by akh

[Moontanman]

 

 

 

http://www.pnas.org/content/early/2011/12/23/1118694109.full.pdf

 

Under enough pressure water will become a solid.

 

T

he phase diagram of H2O exhibits a substantial array of stable

and meta-stable crystalline phases, along with two amorphous

ices (1). Terrestrial experiment continues to find new phases (2).

There are also good cosmochemical reasons to think about the

high pressure phases of H2O—ice is a major component of the

outer planets in our solar system, presumably forming very dense

layers around the rocky cores of Neptune and Uranus (3, 4). And

it is likely that ice will be a constituent of similarly sized or larger

exoplanets that are currently being discovered (5, 6).

 

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

 

Ice VII is the only disordered phase of ice that can be ordered by simple cooling,[3][9] and it forms (ordered) ice VIII below 273 K up to ~ 8 GPa. Above this pressure, the VII-VIII transition temperature drops rapidly, reaching 0 K at ~60 GPa.[10] Thus, ice VII has the largest stability field of all of the molecular phases of ice. The cubic oxygen sub-lattices that form the backbone of the ice VII structure persist to pressures of at least 128 GPa;[11] this pressure is substantially higher than that at which water loses its molecular character entirely, forming ice X. In high pressure ices, protonic diffusion (movement of protons around the oxygen lattice) dominates molecular diffusion, an effect which has been measured directly.[12]

Scientists hypothesize that Ice VII may comprise the ocean floor of extrasolar planets (such as Gliese 436 b and GJ 1214 b) that are largely made of water.[13][14]

bold is mine

 

My very rough calculations seem to show that water in earths oceans would turn to ice at a depth of around 180 miles... I could be off but in fact at some depth water will turn to ice even well above it's Earth melting point. An earth like planet covered by 1000 miles of water would mean that most of that water would be ice even if the atmosphere was steam...

 

A side note, some researchers think the Earth might well have been covered by a very thick layer of water before it collided with a mars sized body that drove most of the water away. If this is true then it might indicate that most Earth sized planets in similar orbits would be mini Neptunes instead of earth like.

 

I am not sure this would be an issue. I think there would still be thermal convections that could cycle the necessary elements.

 

 

You could be correct, there might very well be convictions that would recycle the layers of ice in a similar way that earths mantle has convection currents of molten rock. hard to really speculate on this since we have no real model to base them on.

Edited August 17, 2012 by Moontanman

[akh]

Under enough pressure water will become a solid.

 

 

Sorry, of course this is the case, I should have been more clear about my point. I was trying to say that I think it would be a fairly complex dynamic. The last line of the article you linked (thanks) noted that the ice may actually adopt a fluid state at extremely high pressures.

 

 

A side note, some researchers think the Earth might well have been covered by a very thick layer of water before it collided with a mars sized body that drove most of the water away. If this is true then it might indicate that most Earth sized planets in similar orbits would be mini Neptunes instead of earth like.

 

Do you have any links for this? I couldn't find any, but I would be interested in reading. Sans collision, I would have thought that the majority of the water that ever existed, would have accumulated much later in any case because the Earth was still in the process of cooling after accretion and heavy bombardment. There would also have to be significant enough of an atmosphere to hold water in a liquid state. I think there are competing theories as to where the water actually came from with no real consensus. Most of the theories, whether the water arrived via asteroids or hydrous minerals, necessitates a "rocky" core.

Edited August 17, 2012 by akh

[Moontanman]

Sorry, of course this is the case, I should have been more clear about my point. I was trying to say that I think it would be a fairly complex dynamic. The last line of the article you linked (thanks) noted that the ice may actually adopt a fluid state at extremely high pressures.

 

 

 

 

Do you have any links for this? I couldn't find any, but I would be interested in reading. Sans collision, I would have thought that the majority of the water that ever existed, would have accumulated much later in any case because the Earth was still in the process of cooling after accretion and heavy bombardment. There would also have to be significant enough of an atmosphere to hold water in a liquid state. I think there are competing theories as to where the water actually came from with no real consensus. Most of the theories, whether the water arrived via asteroids or hydrous minerals, necessitates a "rocky" core.

 

Look for the formation of the moon and you should get some hits.

 

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

 

I think the idea that the collision might have caused the Earth to loose it's water and other volatile constituents comes from the book "Rare Earth" I'm not sure this idea occurs anyplace else. I skimmed the book and couldn't find a reference to that, if i come across it again I'll let you know but for now I cannot substantiate that assertion.

[vampares]

Was this Q-ball wearing an inner-tube? Are you sure you didn't get this theory from the "What if the Earth had a big chunk taken out of it?" thread. I think the spots on the near side of the moon show where large object tend towards. Unless there really was a very small population of highly intelligent ape like naturalist humanoids who had a very barbaric but elegant "device" (this culture of super beast individualist -- all WOMEN -- does not have the concept of tools) which catapulted boulders -- no wait they have nuclear capabilities but these are not true weapons, merely incendiary devices -- at the moon with rocket like force. Using the powers of the ocean. The Navy. Simply because they had no other hard target to shoot at. Or maybe they were establishing a system of lakes and reservoirs so they could colonize in the near future. But then they were squashed when Jupiter threw one of it's moon at them.

Edited September 17, 2012 by vampares

[Moontanman]

Was this Q-ball wearing an inner-tube? Are you sure you didn't get this theory from the "What if the Earth had a big chunk taken out of it?" thread. I think the spots on the near side of the moon show where large object tend towards. Unless there really was a very small population of highly intelligent ape like naturalist humanoids who had a very barbaric but elegant "device" (this culture of super beast individualist -- all WOMEN -- does not have the concept of tools) which catapulted boulders -- no wait they have nuclear capabilities but these are not true weapons, merely incendiary devices -- at the moon with rocket like force. Using the powers of the ocean. The Navy. Simply because they had no other hard target to shoot at. Or maybe they were establishing a system of lakes and reservoirs so they could colonize in the near future. But then they were squashed when Jupiter threw one of it's moon at them.

 

 

Can you be a bit more clear as to what you are talking about?

[JohnStu]

Hmm, then I would be Spongebob

[vampares]

OK, the moon of the Earth (does it have a name? no, because it's just one moon) is the largest planetary satellite in our solar system!!!

There is a center of gravitational force and a movement such that if any oversized meteorite were to headed in our direction, it would just miss earth and slam the moon. Saturn or Jupiter had a meteorite hit in recent history, maybe a couple of years ago. It was so large it would have really done damage here on earth. But this never happens. OK, once, if you believe the asteroid theory of Dinosaur extinction. The moon is predominately Al and Si. Not dense at all. Three hours of my shielded metal arc welding looks remarkably similar to the inside of the "mare". Spewed hot metal and sand dust.

 

Analogy:

There earthquakes that are big and there are earthquakes that are enormous. The difference between a 5.0 and a 9.0 is 10,000 fold. When dealing with meteorites, the result of a "large" event would look dramatically different from those little pimples.

 

Mars might look like it had an ocean. Sure and the moon looks like Grover Cleavland. Asteroids fall into the planetary orbital plane easily. Gravity aims these things at the equator. Thats why there looks like it had an ocean at one point but the reality is much colder.

 

And all the Martians lived on either the north pole or the south pole.

[Moontanman]

OK, the moon of the Earth (does it have a name? no, because it's just one moon)

 

Luna...

 

is the largest planetary satellite in our solar system!!!

 

No, Ganymede is the largest moon...

 

http://en.wikipedia.org/wiki/Ganymede_(moon)

 

There is a center of gravitational force and a movement such that if any oversized meteorite were to headed in our direction, it would just miss earth and slam the moon.

 

Again not true... While Luna might absorb some asteroids it doesn't get them all or just get the large ones.

 

Saturn or Jupiter had a meteorite hit in recent history, maybe a couple of years ago.

 

Actually Jupiter just had an asteroid hit it the other day. Two amateur astronomers saw it.

 

It was so large it would have really done damage here on earth. But this never happens. OK, once, if you believe the asteroid theory of Dinosaur extinction.

 

Belief doesn't enter into it, a great many large impacts have scarred the Earth over it's 4.5 billion year history.

 

The moon is predominately Al and Si. Not dense at all. Three hours of my shielded metal arc welding looks remarkably similar to the inside of the "mare". Spewed hot metal and sand dust.

 

I'm not sure how this is relevant to the OP.

 

Analogy:

There earthquakes that are big and there are earthquakes that are enormous. The difference between a 5.0 and a 9.0 is 10,000 fold. When dealing with meteorites, the result of a "large" event would look dramatically different from those little pimples.

 

Can you elaborate on this, how is it relevant to the OP?

 

Mars might look like it had an ocean. Sure and the moon looks like Grover Cleavland. Asteroids fall into the planetary orbital plane easily. Gravity aims these things at the equator.

 

Do you have anything to support this assertion? I see no reason why gravity would aim them at the equator.

 

Thats why there looks like it had an ocean at one point but the reality is much colder.

 

Again some support for this would be nice

 

And all the Martians lived on either the north pole or the south pole.

 

What Martians?

[vampares]

I post a lot of images from the wiki but here is another

This is not a non-issue in our solar system.

Edited September 19, 2012 by vampares

[Moontanman]

I post a lot of images from the wiki but here is another

This is not a non-issue in our solar system.

 

 

Again I am not sure how this pertains to the OP.

[vampares]

Saturn or Jupiter had a meteorite hit in recent history, maybe a couple of years ago.

OK it was an Asteroid, technically.

 

Can you elaborate on this, how is it relevant to the OP?

It is only relevant to the assertion that mars accidentally or intentionally IDK... nudged or rubbed the earth a little and knocked what off? The dead sea? I don't see any red paint.

 

But it is to the point that clearly something did hit the moon but not the earth. It was so large that the impact crater did not leave a bowl shaped poc mark. Instead the creator was relatively shallow in comparison to its width.

 

What Martians?

The former life on Mars that attacks North America and steals the atmosphere.

 

I see no reason why gravity would aim them at the equator.

If you jump off a bridge, do you fall anywhere but straight down? Same thing only this bridge is very, very high (or far away).

 

Belief doesn't enter into it, a great many large impacts have scarred the Earth over it's 4.5 billion year history.

True but none of the knocked the water off the earth or earth. The largest known creator is in South Africa. It is 300km wide.

 

That's the size of South Africa.

 

Again I am not sure how this pertains to the OP.

It is only to the assertion that earth once had that much water on it. no no that mars or some rouge nudged earth and it will happen again to that planet very soon.

 

If a planet did have that much H and O on it, it would be an unlit star, in my opinion. It would not get hit intergalacticly all that often but if it did....where is it the OP's moon unit since he is designing entire planets.

Edited September 19, 2012 by vampares

[Moontanman]

OK it was an Asteroid, technically.

 

either one is ok by me.

 

 

It is only relevant to the assertion that mars accidentally or intentionally IDK... nudged or rubbed the earth a little and knocked what off? The dead sea? I don't see any red paint.

 

Who says that, can you show some support for that assertion?

 

But it is to the point that clearly something did hit the moon but not the earth. It was so large that the impact crater did not leave a bowl shaped poc mark. Instead the creator was relatively shallow in comparison to its width.

 

Again, it is quite plain that a great many things have hit the Moon, many more have no doubt hit the Earth, what is your point?

 

 

The former life on Mars that attacks North America and steals the atmosphere.

 

 

 

If you jump off a bridge, do you fall anywhere but straight down? Same thing only this bridge is very, very high (or far away).

 

Straight down has nothing to do with the equator...

 

True but none of the knocked the water off the earth or earth. The largest known creator is in South Africa. It is 300km wide.

 

Again not relevant.

 

That's the size of South Africa.

 

What is the relevance of that to the OP?

[vampares]

No, Ganymede is the largest moon...

After Ganymede.

[Moontanman]

It is only to the assertion that earth once had that much water on it. no no that mars or some rouge nudged earth and it will happen again to that planet very soon.

 

You are confused, mars did not nudge the Earth, a mars sized body hit the earth and merged with it and in the process formed the moon.

 

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

 

 

If a planet did have that much H and O on it, it would be an unlit star, in my opinion. It would not get hit intergalacticly all that often but if it did....where is it the OP's moon unit since he is designing entire planets.

 

That is just nonsense, a planet would have to be many times bigger than Jupiter to be a star, unlit or not.

 

The OP was asking about a hypothetical planet, why is that a problem?

 

After Ganymede.

 

 

No Luna is the fifth largest moon in our solar system...

 

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

[vampares]

The OP was asking about a hypothetical planet, why is that a problem?

It's not. I just kindof think that there would be too much water on this hypothetical planet.

 

That is just nonsense, a planet would have to be many times bigger than Jupiter to be a star, unlit or not.

Well then get out the Tang, I guess.

 

Of the http://en.wikipedia.org/wiki/Giant_impact_hypothesis

giant collisions are consistent with the leading theories of the formation of the solar system.

Giant collisions would be destructive to the solar system.

 

If this happened to a planet sized glob of water, the water might suround the non-water planet and they would become one.

[assholio420]

1345065343[/url]' post='697197']

Not just on the surface, but down to its core.

 

Let's say eons ago there happened to be a great deal of water in one area of a star system, water that via gravity collected and eventually formed into a planet. Along with gases for atmosphere.

 

There would be enough dissolved minerals for life to develop into living bodies, complex functions, and interconnected ecosystems. Any solid formations would be life-based -- such as coral lattices or floating star trees (named for its wooded shape) -- or disintegrated meteors from the occasional cosmic impact. There may even be flying creatures above water, using large patchworks of star trees as a rest stop.

 

It's a planet with no real land, or even a rocky core.

 

Any scientific problems with this? Can such a planet exist?

 

What happens physically to water at the core, under such pressures?

 

To ward off cosmic radiation, let's assume that a pair of metallic moons orbits it, each at geo-opposite positions and a magnetic field that envelops the planet as the fields merge or overlap.

 

Don't see how a water planet couldn't exist , water seems pretty common out in space , so probably expect to see water planets and if there is liquid water then bound to be life ,but I'm talking normal planet with a lot of water not planet completely made of water