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View Full Version : all the water on Earth is 4.3 or 4.4 billion years old, really ?



bigbang14b
2011-May-06, 03:19 AM
Please read the following quote. I heard it on Terry Gross's show "Fresh Air" on NPR.
The show is dated April 11, 2011 and titled
"The Worldwide 'Thirst' For Clean Drinking Water".
The full transcipt is available at
http://www.npr.org/templates/transcript/transcript.php?storyId=135241362
or Fresh Air's website. My question is: to what extent is Mr. Fishman right ?

I mean, there are so many chemical reactions which break up a water molecule
and its atoms then bond with something else, right ?
so is he not exaggerating ? how is any claim in this regard proven ?

========== Quote Begin ============
Mr. FISHMAN: And all the water on Earth was actually formed in space, in interstellar gas clouds. And it was delivered here when the Earth was formed, or shortly thereafter, in exactly the form it's in.

So all the water on Earth - the water in your Evian bottle, the water in your glass of water, the water you use to boil a pot of spaghetti - all that water is 4.3 or 4.4 billion years old. No water's being created on Earth. No water's being destroyed on Earth. And what that means is the whole debate about reusing wastewater is kind of silly, because all the water we've got right now has been used over and over again. Every drink of water you take, every pot of coffee you make is dinosaur pee, because it's all been through the kidneys of a Tyrannosaurus Rex or an Apatosaurus many, many times, because all the water we have is all the water we have ever had.

============= Quote End ===========================

PetersCreek
2011-May-06, 06:53 AM
Welcome to the BAUT forums bigbang14b. I have moved your post to the Space/Astronomy Questions and Answers forum, where I expect you'll get more answers in short order.

Procyan
2011-May-06, 07:32 AM
H-O-H splits spontaneously or dissociates into H+ and OH-. These ions are free to rejoin to make water or react with other elements and molecules to form many other molecules. OR protons from another molecule may react with OH to make a water...Throw in isotopes and you see a very dynamic, constantly changing lego soup of sorts. So just from that standpoint the statement is incorrect. the water we have now is a mix of protons and oxygen that may have originated in space as hydrocarbons, free elements and ions or any allowed chemical combination, some of which only recently became water on Earth. Of course some of it, perhaps most of it is "in exactly the form" it was when it got here, but its been in a lot of other forms passing through deep time.

eburacum45
2011-May-06, 09:36 AM
Almost all of the water on Earth arrived before 4.3 billion years ago; a small amount of water has arrived since, in the form of icy meteorites and small comets, and a small amount of water has left because of photodissociation and Jeans escape of hydrogen. Some water exists in the form of organic compounds in the biosphere and some in the form of hydrated minerals in the crust. But the basic point is correct - almost no water is being lost on our planet, so there is no real water shortage here.

There is, however, a shortage of clean, fresh water, which is a different thing altogether.

Jason Thompson
2011-May-06, 11:04 AM
But the basic point is correct - almost no water is being lost on our planet, so there is no real water shortage here.

The basic point is not correct. Water molecules have not existed unchanged in all that time. Water is being created and destroyed all the time. You're doing it right now. Hydrolysis and condensation reactions are happening all over the place, especially on a world populated so heavily as this one. The water you breathe out was made from combining the oxygen you breathed in with hydrogen ions from various sources within your body in the process of respiration. Photosynthesis takes water and combines it with carbon dioxide to form glucose. The water you exhale is not the same water that you inhaled, or was exhaled by anyone else, or that any dinosaur drank. The atoms within the molecules may have existed unchanged since then, but not the molecules themselves.

Strange
2011-May-06, 11:25 AM
It depends what you mean by the "same" water, I suppose. Rather like Trigger's broom / grandfather's axe (http://en.wikipedia.org/wiki/Ship_of_Theseus#Cultural_differences)

Ivan Viehoff
2011-May-06, 02:02 PM
I recall posting on a very similar thread a few weeks ago.

One thing that happens to water is that it gets bound up in minerals, for example through soil formation processes, through mineral deposition on ocean floors, through percolation into the ground water and reaction with minerals there, through volcanic processes, etc. These minerals can then get moved deep into the earth's crust through tectonic activity. Some of this then gets lifted up to the surface and exposed by erosion and and released by chemical weathering. Some of it can be released out of volcanoes. Some of it will have a very long residence time in the crust before being recycled. Some even drops down into the mantle.

All that we can really say is that the quantities of water (as free water or ice on the surface, and in ground waters and permafrosts) on earth today are not very different from the quantities 4.3bn years ago, subject to the minor additions #3 mentions.

antoniseb
2011-May-06, 02:12 PM
Fishman didn't say water molecules, he said water, which is a collective noun when thinking about molecules. Water is, as noted above, constantly changing which Oxygen atom each Hydrogen is connected to. One Hydrogen in ten million is changing at any given moment in neutral water at room temperature. That is the state of water. I think the dispute in the OP could be about what fraction of the water on the planet now is composed of Oxygen or Hydrogen that has come to Earth more recently.

Jason Thompson
2011-May-06, 02:27 PM
It may be perfectly true to say that we are not losing water or gaining new water here on Earth as a whole, but the business about it being dinosaur pee and not being created or destroyed is simply rubbish.

This is a big problem in media: they take a perfectly sound scientific idea and then add too much hyperbole to it, to the point of actually making it wrong.

NEOWatcher
2011-May-06, 02:49 PM
This is a big problem in media: they take a perfectly sound scientific idea and then add too much hyperbole to it, to the point of actually making it wrong.
And with this interview.
The guy spends so much time talking about "using water", and "the same water", that it ends up not standing out that he's talking about cleaned water that we are using (and costs associated to clean it).

ETA: A good example in the interview is his talking about bottled water. What does this have to do with the amount of clean water? Whether its from a tap in a reusable bottle, or from a new bottle, it's still the same amount of water that needs to be cleaned. The issue is in the manufacture and distribution.

eburacum45
2011-May-06, 04:16 PM
I believe the point he is making is that our planet has more or less the same amount of water on this planet today as 4.3 billion years ago. This is probably correct, although if I recall correctly continents in that far off era were probably smaller than they are today. If there was the same amount of water then as there is today, the oceans would be slighly shallower on average; but it may be that the oceans were in fact deeper because they contained slightly more water and therefore covered more of the surface of the Earth.

NEOWatcher
2011-May-06, 04:51 PM
If there was the same amount of water then as there is today, the oceans would be slighly shallower on average; but it may be that the oceans were in fact deeper because they contained slightly more water and therefore covered more of the surface of the Earth.
...Or a different ratio of continental ice.

Perikles
2011-May-06, 05:09 PM
What percentage increase in water would the Earth need to be a 100% water planet?

NEOWatcher
2011-May-06, 05:19 PM
What percentage increase in water would the Earth need to be a 100% water planet?

Zero?
Just stop plate techtonics, and let everything erode.

Jason Thompson
2011-May-06, 07:43 PM
I believe the point he is making is that our planet has more or less the same amount of water on this planet today as 4.3 billion years ago.

That probably is the point he is making, and on that point he is very likely correct. But then why add all that rubbish about water not being created or destroyed when it quite clearly is, and about your water having been dinosaur pee? It doesn't help his point at all.

phunk
2011-May-06, 09:09 PM
What percentage increase in water would the Earth need to be a 100% water planet?

There is already enough to cover everything, if you smoothed out the surface.

Githyanki
2011-May-07, 02:48 AM
1. Water's probably a lot older than 4.3 billion years old. What older super-massive stars created the water we have only to expunge it out in a super-nova to have it fall in again and again?

2. There probably weren't many ice-caps on Earth at that time; for a long-time, the Earth's temperature was just below boiling.

danscope
2011-May-07, 05:26 AM
Earth likely enjoyed the collision with a bunch of icy comets 4 to 3 billion years ago , enough of which brought us our oceans . And who knows what was in some of that ice? Life perhaps? Who can say, Grasshopper?
And we still obtain more water , in small quantities all the time .
By the way, nature distills great quantities of pure water each day. If we only took care of our water sheds , we should have a great deal of clean water indeed. And .... yes , we have work to do .

WayneFrancis
2011-May-07, 06:16 AM
unfortunately this man is mixing good science with bad.
Good science
Cleaning waste water for consumption can be a good investment
Bad science
His statements about water's permanentness is not true.


I'm often torn on issues where science is distorted to dumb it down for the general public. This is one case where I'd say telling the real science should be understandable.

IE show how pure the water can be after purification. Compare it to typical water people drink.

Some people will never change their minds but they are a lost cause anyway so no need to lie to them.

WayneFrancis
2011-May-07, 06:19 AM
There is already enough to cover everything, if you smoothed out the surface.

Well yea...if the Earth was a perfect sphere you could cover it with a lot less water...just depends how deep you want to cover it...1 atom or 1km...the difference is huge in the amounts of water.

Procyan
2011-May-07, 06:34 AM
Dinosaurs didn't pee. Thats why they got so big.

They just went no. 2 and made chalk.

Cloaca!

Procyan
2011-May-07, 06:41 AM
Well yea...if the Earth was a perfect sphere you could cover it with a lot less water...just depends how deep you want to cover it...1 atom or 1km...the difference is huge in the amounts of water.

Yes, a vast ocean covering the Earth, 1 atom deep.

danscope
2011-May-09, 01:03 AM
Well.... surely.... it would be deeper than that, surely .

WayneFrancis
2011-May-09, 02:23 AM
Well.... surely.... it would be deeper than that, surely .

Yes it would. About 2.7km deep but my point is the Earth could be just about any size a planet could be and the amount of water we have could cover its surface if its a perfect sphere. If someone wants to do the calculation of how big of a sphere you could have where 1.332x109km3 of water would only be 1 H2O molecule deep then feel free.

...hmmm lets see

3.35x1025 water molecules in 1 litre
1x1012 litre in a 1km3
1.332x109km3 water on Earth
surface area of a sphere 4пr2
1.66x10-10 size of a water molecule
4.4622x1046 molecules of water on Earth
7.407252x1036 surface area of hypothetical body
5.9x1035 = r2
~767,756,722,708,218,267m
or ~81 light years in radius

hmmm that is a tad bigger then I'd have thought but hey...someone double check my maths...I'm pretty sure that is close ... just rechecked..but then if I screwed up the formulas and values then I'd get the answer wrong twice :)

Perikles
2011-May-09, 08:08 AM
Well, my point in asking was to see how unlikely it was that, given the unevenness of the Earth's surface, the amount of water on the Earth was sufficient enough to produce the right climate, yet little enough to allow some land mass for 'intelligent' life to evolve. Without having any figures, I'm guessing that the range of acceptable water mass could be quite small, which could be a significant factor for the probability of finding life elsewhere. Or maybe not.

Van Rijn
2011-May-09, 09:01 AM
Keep in mind that if the water concentration is too small, for even a perfectly spherical world of porous rock, there will be no surface water, just an impurity in the rock. If there isn't a lot of water under the ground, there won't be any above it.

WayneFrancis
2011-May-09, 11:21 AM
Keep in mind that if the water concentration is too small, for even a perfectly spherical world of porous rock, there will be no surface water, just an impurity in the rock. If there isn't a lot of water under the ground, there won't be any above it.

Ummm well Lets say my 81ly radius planet is non porous :P

WayneFrancis
2011-May-09, 11:24 AM
Well, my point in asking was to see how unlikely it was that, given the unevenness of the Earth's surface, the amount of water on the Earth was sufficient enough to produce the right climate, yet little enough to allow some land mass for 'intelligent' life to evolve. Without having any figures, I'm guessing that the range of acceptable water mass could be quite small, which could be a significant factor for the probability of finding life elsewhere. Or maybe not.

1) what does land have to do with intelligent life?
2) what does that have to do with life in general somewhere else?

Perikles
2011-May-09, 01:05 PM
1) what does land have to do with intelligent life?
2) what does that have to do with life in general somewhere else?I'm not claiming there has necessarily to be any connection at all, only that we have one and only one example of the evolution of 'intelligent' life, and that evolution has involved land masses. How many intelligent fish do you know of?

Cobra1597
2011-May-09, 01:24 PM
Well, my point in asking was to see how unlikely it was that, given the unevenness of the Earth's surface, the amount of water on the Earth was sufficient enough to produce the right climate, yet little enough to allow some land mass for 'intelligent' life to evolve. Without having any figures, I'm guessing that the range of acceptable water mass could be quite small, which could be a significant factor for the probability of finding life elsewhere. Or maybe not.

What does "right climate" mean, for that matter? The climate is right for us, sure, but that's because we adapted to it. If the climate had been different, we would have adapted to that different climate (or gone extinct, in which case something else probably would have adapted to it).

I had this same discussion with my biology professor last semester. She found it absolutely amazing that the band of the EM spectrum that we can see, the band that plants absorb for photosynthesis, and the band at which the sun's output is at its peak are all roughly the same. She found this to be an amazing coincidence, but to me it just made sense as a product of natural selection. Any plant that absorbs light at the sun's peak wavelength output is going to be more efficient at capturing solar energy than a plant that does not. Any plant that is so much more efficient will have a stronger ability to thrive than any plant that does not absorb at the solar radiation peak. So, green plants win at natural selection. The same goes for humans. A daylight animal that can see light reflected off of objects in the sun's peak intensity wavelengths is going to be able to see better than one that cannot (barring some other use for sight, like thermal tracking). That ability to see better translates to better success, and winning at natural selection.

Plants and humans have adapted to sun's peak intensity wavelength output. If the sun were a different color (and we didn't freeze or burn to death first), plants would have evolved as a color other than green, and humans would see light in a different band than the current visual spectrum one. It isn't some magical coincidence.

Just the same, it isn't some magical coincidence that the conditions on Earth are very well matched and suited to the conditions needed by the life living on it. Life has evolved to thrive within those conditions, adapted to those conditions, and changed with them as those conditions have changed over time. If there had been less water on Earth and therefore a different climate, life would have adapted to those conditions and would find our existing climate to be hostile.

Cobra1597
2011-May-09, 01:25 PM
I'm not claiming there has necessarily to be any connection at all, only that we have one and only one example of the evolution of 'intelligent' life, and that evolution has involved land masses. How many intelligent fish do you know of?

Certain species of sharks, as well as dolphins and other cetaceans, come pretty close. One example is not enough to start determining trends.

Strange
2011-May-09, 02:00 PM
She found it absolutely amazing that the band of the EM spectrum that we can see, the band that plants absorb for photosynthesis, and the band at which the sun's output is at its peak are all roughly the same. She found this to be an amazing coincidence ...

And if a biology professor can think that, it is no wonder that many people find ideas like ID compelling. To stay on topic: isn't it also amazing that there is just enough water on Earth to fill all the oceans and rivers ... :neutral:

Cobra1597
2011-May-09, 08:34 PM
isn't it also amazing that there is just enough water on Earth to fill all the oceans and rivers ... :neutral:

Not all of them (http://en.wikipedia.org/wiki/Western_Interior_Seaway). :razz:
But then, I rather like Colorado.

Strange
2011-May-09, 08:48 PM
Not all of them (http://en.wikipedia.org/wiki/Western_Interior_Seaway).

Cool. I never knew that. I love this place!

WayneFrancis
2011-May-10, 12:05 AM
I'm not claiming there has necessarily to be any connection at all, only that we have one and only one example of the evolution of 'intelligent' life, and that evolution has involved land masses. How many intelligent fish do you know of?

Well...not so much "fish" but there are some pretty intelligent species of cephalopods out there.

neilzero
2011-May-12, 04:36 AM
So Mr. Fishman is at least slightly wrong on almost every point. Earth has received several parts per billion additional water from space in the last billion years and lost about that much to outer space over the past billion years. I suppose there is some pristine water, but most of it has participated in a chemical reaction of some sort. Not every molecule has been though kidneys, perhaps not even half of them.
Am I in error to think the hot interior of Earth tends to keep most of the water in (or on) the crust? Do we have 0.01% steam all the way to the center, both mantle and core? Neil

Cougar
2011-May-14, 01:50 AM
Mr. FISHMAN: And all the water on Earth was actually formed in space, in interstellar gas clouds. And it was delivered here when the Earth was formed, or shortly thereafter, in exactly the form it's in.

Yes, this is rather... sensationalist. Of course, everything in the universe "formed in space." A lot of H2O doesn't seem so strange, particularly since Oxygen is the 3rd most abundant element in the universe after Helium. And to claim it was delivered "in exactly the form it's in" certainly seems ambiguous and misleading. Other than that, yes, water is good. Except when it floods your house.

wd40
2011-May-14, 06:19 PM
How and when did the ocean's reach their current salinity?

Would a higher or lower salinity in the past have increased or reduced the amount of salt-free clouds that can evaporate from their surface?

Cobra1597
2011-May-14, 07:40 PM
Would a higher or lower salinity in the past have increased or reduced the amount of salt-free clouds that can evaporate from their surface?

What exactly do you mean by this?

wd40
2011-May-14, 09:19 PM
Does the concentration of salt in the sea affect the volume of water vapor that can be evaporated from it per hour by the Sun to form clouds?

If the seas were less saline in the past, would this have affected rain fall around the world?

Cobra1597
2011-May-14, 09:56 PM
Higher salinity solutions tend to have higher boiling points, meaning it is harder to boil them or evaporate them. That said, in considering this question you have to think more about what caused the salinity of the Earth's oceans to be different in the past. It wasn't caused by some giant salt shaker in the sky.

As I understand it, the biggest thing effecting change in the salinity of the Earth's oceans is how much water is locked up in the polar ice caps. As more or less water is trapped in the poles as ice, the amount of liquid water for salt to dissolve in the oceans changes, and therefore so does the salinity. One of the predicted effects of melting glacial water from AGW is a decreased ocean salinity, which can potentially have other effects (I've heard things like changing ocean currents, for example).

Less water in the ice caps is generally a result higher overall global temperatures. So when the Earth is warmer, there is more meltwater, and the salinity of the oceans drops, and the boiling point of the water drops. Evaporation happens more easily both because of the lower boiling point and higher overall global temperature. There is now more moisture in the air for cloud formation.

Past that I'm not sure I'm knowledgeable enough to help. I don't know enough about the variables impacting cloud formation to make a good guess at how all of this would impact the amount of new clouds, or how much precipitation there would be. The air would be more humid, but I don't know for sure if it would rain more. I'd guess that it would.