How Did Earth Get Its Water? 40
Earth's water could have originated from interactions between the hydrogen-rich atmospheres and magma oceans of the planetary embryos that comprised Earth's formative years, according to new work from Carnegie Science's Anat Shahar and UCLA's Edward Young and Hilke Schlichting. Their findings, which could explain the origins of Earth's signature features, are published in Nature. Phys.Org reports: "Exoplanet discoveries have given us a much greater appreciation of how common it is for just-formed planets to be surrounded by atmospheres that are rich in molecular hydrogen, H2, during their first several million years of growth," Shahar explained. "Eventually these hydrogen envelopes dissipate, but they leave their fingerprints on the young planet's composition." Using this information, the researchers developed new models for Earth's formation and evolution to see if our home planet's distinct chemical traits could be replicated.
Using a newly developed model, the Carnegie and UCLA researchers were able to demonstrate that early in Earth's existence, interactions between the magma ocean and a molecular hydrogen proto-atmosphere could have given rise to some of Earth's signature features, such as its abundance of water and its overall oxidized state. The researchers used mathematical modeling to explore the exchange of materials between molecular hydrogen atmospheres and magma oceans by looking at 25 different compounds and 18 different types of reactions -- complex enough to yield valuable data about Earth's possible formative history, but simple enough to interpret fully.
Interactions between the magma ocean and the atmosphere in their simulated baby Earth resulted in the movement of large masses of hydrogen into the metallic core, the oxidation of the mantle, and the production of large quantities of water. Even if all of the rocky material that collided to form the growing planet was completely dry, these interactions between the molecular hydrogen atmosphere and the magma ocean would generate copious amounts of water, the researchers revealed. Other water sources are possible, they say, but not necessary to explain Earth's current state. "This is just one possible explanation for our planet's evolution, but one that would establish an important link between Earth's formation history and the most common exoplanets that have been discovered orbiting distant stars, which are called Super-Earths and sub-Neptunes," Shahar concluded.
Using a newly developed model, the Carnegie and UCLA researchers were able to demonstrate that early in Earth's existence, interactions between the magma ocean and a molecular hydrogen proto-atmosphere could have given rise to some of Earth's signature features, such as its abundance of water and its overall oxidized state. The researchers used mathematical modeling to explore the exchange of materials between molecular hydrogen atmospheres and magma oceans by looking at 25 different compounds and 18 different types of reactions -- complex enough to yield valuable data about Earth's possible formative history, but simple enough to interpret fully.
Interactions between the magma ocean and the atmosphere in their simulated baby Earth resulted in the movement of large masses of hydrogen into the metallic core, the oxidation of the mantle, and the production of large quantities of water. Even if all of the rocky material that collided to form the growing planet was completely dry, these interactions between the molecular hydrogen atmosphere and the magma ocean would generate copious amounts of water, the researchers revealed. Other water sources are possible, they say, but not necessary to explain Earth's current state. "This is just one possible explanation for our planet's evolution, but one that would establish an important link between Earth's formation history and the most common exoplanets that have been discovered orbiting distant stars, which are called Super-Earths and sub-Neptunes," Shahar concluded.
Same as everyone else (Score:1)
From the tap or a bottle.
Thank you, thank you folks, I'll be here the rest of the night and every day ending in "y".
Re:Same as everyone else (Score:4, Funny)
Darn, I was hoping to FP with "from the Culligan Man [youtu.be], of course!"
Re: (Score:2)
Doh! Sorry, that's so much better. I'd delete mine for you if they let us.
I Would Tell You But You Wouldn't Believe Me (Score:2)
So I will leave it at that.
Re: (Score:1)
Just pointing out the pattern here: I'm only ever modded down for telling the truth.
Re:God spilled a lot of beer (Score:5, Funny)
It may have been the same color as beer, but I don't think it was beer. The Earth's water tastes salty, I'll leave it at that.
Fascinating. (Score:3, Interesting)
The provides a clean means for water production, given that hydrogen was everything in the early formation of everything.
Re: Fascinating. (Score:2)
Turtles are generally aquatic critters. Perhaps they passed some up?
Re: (Score:3, Insightful)
Re:Fascinating. (Score:4, Interesting)
IIRC the isotope ratio in comet water does not match the terrestrial water.
The D/H ratio is significantly different, but I believe it is based on, like, ONE data point (Comet 67P/Churyumov–Gerasimenko). Let's look at some more comets before jumping to conclusions.
But TFA is asking the wrong question. Rather than asking where Earth's water came from, we should be asking where it went. Most simulations of the early solar system result in Earth having far more water than it currently does. It should be a "water-world" like Europa and Ganymede.
So where did all the water go? The most accepted hypothesis is that it was lost in the Theia collision [wikipedia.org] that formed the Moon.
Another mystery is: Where did all the neon go?
Neon is plentiful in the solar system but very rare on Earth. It has a molecular weight of 20, while water vapor is 18. So why does the Earth have water but no neon?
Re: (Score:2)
That's certainly not wrong. Another instructive example of a "water world" in this context is, of course, Venus.
Not because it's a "water world" like Ganymede or Europa, but because it is currently (and probably always has been)
Re:Fascinating. (Score:5, Interesting)
Pretty much everything you need in significant mass in the system comes from the original cloud that collapsed into a star and dust ring. You can go further back than that all the way to the Big Bang if you want, but in terms of planetary formation that cloud is a good enough starting point.
Anywhere you get the right amount of mass with the right amount of metals in it, you'll get the 'right' kind of star and rocky worlds.
Earth isn't special as in 'unique', in fact I'd bet on it being near dead average... for rocks near its mass in the goldilocks zone of an orange or yellow dwarf star of high metal content in a region of space that isn't too densely populated.
Re: (Score:3)
Just to chime in Oxygen is the third leading element in our sun, behind hydrogen and helium. From there we have Carbon, followed by Nitrogen. Which lines up with the whole, our sun is a more recent generation star. There's been plenty CNO cycle stars before ours and that eventually makes its way into our star. It's estimated that the sun currently has about 0.97% oxygen of it's total 1.9891 x 10**30 kg, that leaves us with roughly 1.929427 x 10**28 kg of oxygen within the sun, which isn't much compared
How can you *avoid* water? (Score:3)
I never really understood the question.
The most common element in the universe is hydrogen. Oxygen is in the top 4 (CHON) - all of which are vastly more common than anything else.
You put hydrogen and oxygen in the same place and add heat or spark (both of which are likely common in condensing proto-stellar and proto-planetary clouds) and they *will* burn, producing water, which is a pretty fracking stable molecule.
It seems like the only way you *wouldn't* get huge amounts of water on an early planet, is if
Re: (Score:2)
Indeed, what happens in the few hundred million years "after" formation of a planet is quite important. For example, models of Jupiter's formation suggest it may have taken only 20-odd million years to form. But the period of "orbital billiards" between the gas- and ice- giants, probably took twice that long. And estim
From the tears of angles (Score:2)
Magrathea (Score:4, Funny)
Nestle (Score:2)
It was brought here by Nestle
Here is how the Earth got its water (Score:3)
Earth got its water from hydrogen and oxygen in the nebula that formed the Sun and its planets. The hydrogen came from the big bang, and the oxygen came from one (or more) older, bigger stars than the sun that could fuse helium into heavier elements (including oxygen), then went supernova and basically formed the sun's nebula.
Hydrogen is a strong reductant, and oxygen is a strong oxidant, so they readily react and produce water. Although, there is also a lot of oxygen bound to silicon in silicate and other minerals, and also nowadays some hydrogen is bound to carbon due to various biological processes, e.g. photosynthesis.
The remaining question is, why does Earth have water, when the other inner planets (Mercury, Venus, Mars) don't? That is because most water that was present on those planets has escaped, due to either high temperature (Venus), low gravity (Mars) or both (Mercury). Earth has fairly high gravity and low temperature, so that water generally stays on the surface.
Next question?
Re: (Score:1)
Wasn't Mars because of weak magnetosphere since the core is solid, leaking all the atmosphere, and water, into space?
I was wondering what that rate would be since terraforming Mars by adding atmosphere is just going to leak off again, so that process will never end.
Re: (Score:2)
You're right. The Musk-o-philes are going to hate you for pointing that out.
Of course, you could just make a bigger atmosphere. By ... I estimate that you'd need more than half the mass of the asteroid belt - before you start fixing the chemistry. That's going to be hundreds of thousands of Chixulub-size impacts. And some that are - in relation to Mars - not far off the Earth's "Moon-forming" [wikipedia.org] impact, or Mar's (possible, disputed) "hemispheric dichotomy" [wikipedia.org] impact. Better do thos
Re: (Score:1)
lol that's.....a tad more extreme than I was expecting. I think I brought this up before somewhere, and the response was basically that we are good at dumping Co2 into our atmosphere already, so our polluting ways would be a boon on Mars. Of course this says nothing about chemistry as you mention. Nothing to filter all that water like Earths biosphere probably means bad things. Earth was deadly to life before it was friendly.
Might be easier to just restart Mars core. haha.
Re: (Score:2)
An atmosphere of 6% CO2 is still pretty debilitating to humans. Fortunately, the atmosphere of Mars isn't dense enough to be poisonous. It could be 10% v/v H2S, and it wouldn't be (quite) an immediate knock-down followed
Re: (Score:1)
hmm a lot of interesting points there, but I think people were hoping to use the planet while transforming it. heh. I suppose they will have to settle for something far less transformative, unless there happens to be a alien reactor hiding somewhere that is.
Re: (Score:2)
Re: (Score:2)
Re: (Score:3)
Some form of "waters" was there before t
More interesting: Goldilocks water amount on Earth (Score:3)
If you look at the other planets in the solar system they are essentially mostly dry deserts (like Mercury or most of Mars) or in a few cases possibly 100 mile deep oceans under ice crusts (like moons of gas giant planets such as Europa). While watery moons are more hopeful for life, it is still problematical to sustain life for the long term with 100 mile deep oceans because there is (presumably) little nutrient cycling -- unlike the Earth where plate tectonic uplifts land that weathers into runoff going into the ocean. So what is really strange (and potentially extremely rare) about the Earth may be that it has only 71% covered by water and that water is only on average only about a mile deep. If the Earth had, say, about twice as much water, then it might have almost no dry land except the peaks of some tall mountains. If the Earth had 10X the amount of surface water, it would have no dry land. If Earth had 100X the amount of water then even life in the oceans might be impossible long term -- from lack of nutrient cycling and an inability of life to access nutrient 100 miles under water on the ocean floor. The exact balance of just a little surface water (relatively speaking) but not too much might be a key factor in the Drake equation? I would suspect that it is very rare to have a planet with Earth's just right amount, and instead most planets have too much or too little water for any life, let alone intelligent life. I might be wrong, but for some reason I have been thinking about this a bunch the last couple of years after seeing some web pages about how life probably could not exist on a world with very deep oceans.
Related: https://en.wikipedia.org/wiki/... [wikipedia.org]
"An ocean world's habitation by Earth-like life is limited if the planet is completely covered by liquid water at the surface, even more restricted if a pressurized, solid ice layer is located between the global ocean and the lower rocky mantle. Simulations of a hypothetical ocean world covered by 5 Earth oceans' worth of water indicate the water would not contain enough phosphorus and other nutrients for Earth-like oxygen-producing ocean organisms such as plankton to evolve. On Earth, phosphorus is washed into the oceans by rainwater hitting rocks on exposed land so the mechanism would not work on an ocean world. Simulations of ocean planets with 50 Earth oceans' worth of water indicate the pressure on the sea floor would be so immense that the planet's interior would not sustain plate tectonics to cause volcanism to provide the right chemical environment for terrestrial life."
Re: (Score:2)
That's included in the "F[sub]l" parameter - the proportion of planets that have life, out of all planets.
Yeah, we could divide each and every one of the Drake parametrisation factors into a dozen sub factors. But how useful would that be? We're getting reasonably tight on the "number of stars parameter" (grace of the Gaia mission; the numbers are stable within a factor of better than 10. For the fraction of stars with planets, we're acquiring data to make it wo
From whence came the oxygen? (Score:2)
Yes, hydrogen is pretty abundant. But oxygen doesn't just float around in molecular form. It's too reactive. In the beginning, Earth was a big iron ball. Which rapidly rusted in contact with the oceans, forming iron oxide. It wasn't until much later that cyanobacteria evolved and started munching on CO2, producing oxygen. CO2, being less reactive than O2 got here, or was produced here first. Probably in conjunction with water already present. Earlier on, a hot, magma ball Earth may have cooked something to
The creation of water is simple. (Score:1)
Re: (Score:2)
Re: (Score:1)
Genesis 1:2 (Score:1)
The Sumerians have an answer. (Score:1)
The Sumarians have an answer to this question. Another, larger planet (on a 10-thousand-year orbit, on an off-plane axis) impacted the planet which we know as Earth today. The result was a donation of that planet's waters to Earth. This explains why we've got comets with such a similar water composition to Earth, and why there are 2 water types in the comets (one from each planet).
NASA confirms this line of reasoning.
https://www.nasa.gov/feature/comet-provides-new-clues-to-origins-of-earth-s-oceans/
Given we
Re: (Score:2)
The evidence we have from debris from large impacts within the Solar system is that the smaller body in such impacts does not survive well. Indeed, does not survive identifiably.
So even if your Sumerians (evidence, please ; not from the "Flat Earth Journal of Fruit-Loopery") did postulate such an impact (what is the cuneiform for "giant impact"? I'll ask a cuneiform expert, next time I see one.), then there wouldn't be an Earth left after the impact for us t