A ball of water the size of the earth

Maddad · Nov 27, 2004

What are these more interesting properties of Ammonia?

silylene old · Nov 27, 2004

Well... - It's a good solvent for polar and ionic compounds, but not as good as water. - It's a better solvent than water for non-polar compounds (this is a biggy). - More likely than water to take a proton (NH4+) - Less likely than water to lose a proton (NH2-) - Stronger reducing agent - Heat of evaporation is about half of water - Compresses easily to a liquid. At 20 atm, its liquid range is double that of water and encompasses the temperature range of known life. - More easily forms alkaline solutions than water - Reacts with acids - Dissolves large quantities of group I and group II metals to form beautifully colored complexes - this is very cool (solvated electrons!) - Solvated electrons - Excellent solvent to prepare hundreds of transition metal organometallic compounds (unlike water, which will hydrolize and destroy them), especially coordination compounds. Can be a solvent to prepare polymeric coordination compounds. - very low viscosity - high dielectric constant - good solvent for many organometalloid synthesis reactions - good solvent for dozens of important organic synthesis reactions <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

thalion · Nov 28, 2004

I've always been interested in the possibility of ammonia seas on other worlds, but IIRC, ammonia is too reactive, and too likely to be overwhelmed by a more common compound like water to be a common oceanic substance. I suppose we could make do with seas of ammonium hydroxide. <img src="/images/icons/wink.gif" />

silylene old · Nov 28, 2004

Thalion, since this is a very speculative thread, I was making a simple point that a globe of liquid ammonia would be at least as interesting as a globe of water. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

Maddad · Nov 28, 2004

Interesting comments on ammonia. The bit about proton doning a is redundant with reacting with acids and being a reducing agent. An proton donner is an acid. It's a major difference with water which is acid-base balanced. I'm guessing that the ammonia molecule is electrically non-polar since it is a good solvent for non-polar substances. On a high pressure world it would be thermally stable over a wide range. I'm thinking about inside the clouds of Jupiter. And the comment about the transition metals makes it different from water. The viscosity is something that I should have considered, but didn't. Overall it was an excellent post.

meteo · Nov 28, 2004

I'm guessing that the ammonia molecule is electrically non-polar since it is a good solvent for non-polar substances. It's polar pyramidal-shaped, N on one end H's on the other.

silylene old · Nov 28, 2004

Maddad: Ammonia is "acid base balanced" too, in the anhydrous state, in the sense that equal amounts of the protonated form and the deprotonated form exist. 2NH3 <-- /> NH4+ + NH2- I think perhaps what you are refering to is what happens when ammonia is dissolved in water. In water, it's a base: NH3 + H2O <-- /> NH4+ + OH- (equilibrium sits at the right) In water solvent, acids are "leveled" to the acidity of hydronium, H3O+ and bases are "leveled" to the basicity of hydroxide, OH- . In other words, and acid stronger than the conjugate acid of water will cause H3O+ to form; and a base stronger than the conjugate base of water (for example, sodium methoxide) will cause hydroxide to form. In a similar manner, NH3 as a anhydrous solvent also "levels" the acidity to that of the ammonium ion, NH4+, and levels the basicity to that of the amide ion, NH2- . Perhaps what meant is that an acid which is a "weak acid" in water, such as acetic acid, is a strong acid in anhydrous ammonia: In other words, CH3COOH + H2O <-- /> CH3COO- + H3O+ (equilbrium is no the left) but CH3COOH + NH3(liq) <-- /> CH3COO- + NH4+ (equilibrium on the right) Similarly, a base which is strong in water, may be weak in NH3(liq). However some bases, which are strong in water, remain strong in ammonia too (such as sodium methoxide). Ammonia is polar, since it is a pyramidal molecule composed of atoms of differing electornegativity (as is water). liquid...................dipole moment (in Debyes) H20...................... 1.8 NH3...................... 1.5 Br2....................... 0.0 benzene............... 0.0 Ammonia can be a reducing agent when solvated electrons are present. For example, dissolving sodium or other alkali metals into NH3(liq) forms a beautiful blue and gold solutions which are a powerful reducing agent. Also, these solvated <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

Maddad · Nov 29, 2004

Thank you. It is always a pleasure talking with someone who knows his science. I've probably learned more about ammonia than I ever wanted to know *L*

Saiph · Nov 30, 2004

okay, lets run with this. Water won't be found..but can we find another material that will be found, can be liquid, and boils in space? Sure! HYDROGEN and HELIUM. And...wow, they do form planets, just as we've been describing. You have a liquid hydrogen core (metalic as well) maintained in that state due to the pressure of an overlying gaseous hydrogen atmosphere (i.e. as much as can boil, has, now it's done), that doesn't escape of into space because there's a enough mass to keep it captured. So, what have we done with our ideas? Oh, switched compounds and hypothetically stuck it together. Sure, it'll never be found in nature. But then agian, I can run calculations to see what would happen if we took an earth made of antimatter and collided it with venus, and predict how much energy would result. Sure, it won't happen. Doesn't mean my idea and reasoning are invalid. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Saiph · Nov 30, 2004

wow, you just like being contrary don't you? 1) Nobody is saying such a water world would ever form naturally 2) This is a general: What would happen if.... Along the lines of what would happen if the sun was replaced with a black hole? Or do you froth at the mouth over that question as well? 3) Yes, it would, in nature, in reality, be a composite, great. Did I ever deny that? 4) Surface water is thin, sure, but there's also a lot locked into the mantle, the amount I can no longer recall, but it's several 10's of times more than in the ocean. Just so you know. I.e. surface water isn't everything. 5) My example of hydrogen and helium planets (i.e. jovians) and how they work was to support the statements above that pertain to the physics involved in such an impossible water planet. Basically to point out that such a planet, should it be formed (however, if ever blah blah blah) would not, as you stated, boil of into space completely. That once formed it would be stable. 6) So, you're right, it would never form in any state where water has such an overwhelming majority of the composition. But once formed, such a state is relatively stable (less so than earth, but stable) if the total mass and local temperature allow it to keep water (i.e. water molecules don't achieve escape velocity). So cool your jets. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

mental_avenger · Nov 30, 2004

As long as we know these are all hypothetical 'balls', which have no bearing on real, existing events..... WEll, they are hypothetical for the purpose of this discussion, but that does not mean that they cannont exist somewhere. It is possible that such a ball of water does in fact exist somewhere in the Universe. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

mental_avenger · Nov 30, 2004

1) Nobody is saying such a water world would ever form naturally I am. Maybe it is a low probablity, but given the incredibly huge number of galaxies in the Universe, each with millions to billions of solar systems, it seems possible. 3) Yes, it would, in nature, in reality, be a composite, great. Did I ever deny that? That would depend on the mechansim of formation, wouldn't it? Perhaps a ring of water ice bergs, left over after the formation of a planetary system. Who knows what is possible with so many quadrillions of random combinations taking place over seventeen billion years. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

Maddad · Dec 1, 2004

steve "So, we'll not find any balls of water or NH3. We are imagining what would happen if we did find such an object. We are not interested in the question of whether we will. Learn to think; it won't hurt you.

silylene old · Dec 1, 2004

A ball of liquid HF would be just very interesting also. Liquid HF has some unusual properties. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

nexium · Feb 7, 2005

A very advanced race could likely assemble a planet with only water with a radius of 4000 miles = same size as Earth. It would have a very thin water vapor atmosphere assuming an average surface temperature of 56 degrees f. It would have less than 1/2 the mass of Earth, so the surface gravity would be about 1/2 that of Earth's surface. The surface temperature could be the result of formation, in which case it would be cooling. Cosmic radiation might be a million times less than in Earth's upper atmosphere, so only a few pounds of water vapor would be dissasociated per day. As little as one pound per year of hydrogen lost to space per year. Some hydrogen recombines with free oxygen and perhaps a pound hydrogen would be swept up annually even in the great voids between the galaxies. If there was a sun like ours, 92 million mile away, Hydrogen would be lost in a million years, resulting in an oxygen atmosphere which could hold more water vapor than vacuum, I think. Because of the low gravity, small amounts of oxygen and water vapor would also be lost to space, but the planet would likely last a billion years. More practical, they would likely start with a planet, like Mercury, but bigger and with scarcely any volitiles, and add a thin veener of water. This would give a surface gravity about the same as Earth with a thin water vapor atmosphere. Hydrogen loss would be perhaps 100 times less than for the 1/2 gravity water planet. Oxygen and water vapor loss would be negligible, unless radiation was much more intense than we get. A probable magnetic field would also reduce atmosphere loss at least slightly. A water only planet probably cannot have a magnetic field. A water only planet with 12 times the mass of Earth would have about three times the radius and perhaps 1.5 times the surface gravity of Earth and would loose negligible atmosphere to space even in a some what stronger radiation than we get from our sun. At the core of a water only world, high density

thalion · Feb 7, 2005

In the old days I liked to imagine worlds with atmospheres of chlorine and oceans of aquaeous HCl. That was, of course, before I found out that those substances are way too reactive to be realistic volatiles on a planet's surface, but a guy can dream, right?

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