Where did the Earth's Water Come from?

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  • Written By: Michael Anissimov
  • Edited By: Bronwyn Harris
  • Last Modified Date: 20 September 2019
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Earth is located within the "snow line" of the solar system, the region closest to the Sun where H2O is primarily in liquid or gaseous form, if at all. The snow line is located in the outer asteroid belt, between the orbits of Mars and Jupiter. The snow line phenomena is reflected in the water content of planets like Mercury, Venus, and Mars. Water is absent on Mercury. On Venus, H2O only exists as a trace element in the atmosphere. Mars only has a thin veneer of ice in its polar regions. In general, water is rare within the snow line.

Why does Earth have so much water relative to the other inner planets? 71% of the surface is covered in the oceans, more than half of which is deeper than 3,000 meters (9,800 ft), with an approximate total volume of 1.3 billion cu km (310 million cu mi). Still, the oceans only make up 0.023% of the Earth's total mass.


There are various theories as to where all the Earth's water came from, but several theories have fared better than the others. We know that the oceans existed as early as 100 million years after the formation of the Earth. When the Earth was in the process of forming, with a radius just 40% smaller than at present, it would have had enough gravity to hold on to a tenuous atmosphere with water vapor. The first water vapor on the planet would have come from the planet's internals, where volatile (low weight) chemicals would have a tendency to float to the top, and heavy chemicals (iron and nickel) would sink.

Though the first of Earth's water came about through volcanism, this alone probably didn't produce enough to form stable pools on the surface. More water was added to the planet during several hypothesized large impacts from asteroids from the outer asteroid belt. Comparing the isotope ratios of water on Earth and water from comets and asteroids has revealed that the majority of the Earth's water comes from asteroids.

Throughout its history, Earth's water has increased in volume due to biological processes. In the early seas of Earth, hydrogen sulfide would have been in great supply, which, when reacted with carbon dioxide from the atmosphere during photosynthesis in sulfide-reducing bacteria, would have produced hydrogen, sulfur, and water. Many geologists believe that the majority of Earth's water generated through this process.


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Post 15

The answer is actually very simple. The sun creates oxygen and the universe is primarily hydrogen. The center of the earth is magma and the answer is that the earth was once a star/sun which for some reason stopped growing due to a lack of star food and started cooling down and thus, the water from this dying star/sun, now known as earth, formed on the cooled crust of this planet. Peter S.

Post 14

Water only exists so much on earth because other planets are too close or too far from the sun to have water.

Post 13

It is quite possible that a combination of asteroids, volcanic activity, chemical interaction and other processes all contributed to the earth's water. It would not have taken much for a cooling, newly formed planet to produce a thin sheen of water once an atmosphere is present. And our oceans are really only two to seven miles deep on a planet 8,000 miles in diameter, no more significant proportionally than the condensation on a glass.

I would, however, caution against taking Miles Mathis seriously. He is not a scientist and has never done the work it takes to become one. This is why he makes undergrad level errors in concept and math in his "papers". He declares Einstein, Euclid and dozens

of other scientists and mathematicians wrong, yet he cannot see his own errors. Unlike these others, Mathis toils away in isolation, never consults anyone else to check his work, never submits his papers for peer review, and never cites any peer reviewed studies. He only refers to his previous ideas.

Mathis is a terrible time waster and has led many inquisitive people astray with his pseudo-science. And real scientists don't vanity publish their books and they don't solicit money on their websites. Please save your reading for works by accredited scientists.

Post 10

I agree with the above, why do we have to note the same thing again and again? Where is the permanent advance? Will we say the comet is disprovable again next decade?

I can see the why of Miles Mathis. He has put all his insight and plenty of that on the net for all of us.

I think the major question here is: Which came first? The water or the well of gravity?

We are told that we are not made to stand upright, too much stress on the body structure. Well, if you agree with that and I do, then the logical conclusion is that we were made in a lighter gravity, or to put it another way, on a planet that had as much photon charge as E/M, etc. Matter and anti matter. We readers shouldn't have to be constantly frustrated by this repetitive and disconnected science bits.

Post 8

The research that I have read disputes a key assertion here. It indicates that the ratio of water isotopes in comets varies significantly to the proportions found on earth and therefore do not substantiate the theory that most of the water came from that source.

Post 7

what amazes me is that scientists study these things around the clock and still deny the existence of the creator.

"And if you obey most of those on earth, they will mislead you far away from Allah's Path. They follow nothing but conjectures, and they do nothing but lie" QURAN 6:116.

Post 6

There are approximately 333 million cubic miles of water on Earth today. It was stated that the majority of our water came from comets and asteroids. If the Earth is 4.5 billion years old we would have to have obtained 74 trillion gallons of water every year from comets and asteroids.

Post 4

Where did this bacteria arise from? I thought the water was here first then life. Am I mistaken or can bacteria live with no water?

Post 3

the water on earth was tested against the water of the tail of Hailey's and found not to be consistent scientifically.

Post 2

From what I have read, and watched, eater is not the only mystery. Why is our DNA coded like a computer program. If you put the code in the correct order you can make an ear, an eye or whatever.

Life was put here on earth by higher intellegence and I believe, we have been guided throughout time by this intellegence. I am not saying a snapping finger and it is done type God. But a superior intellegent race other than our own.

If the seeable universe is 14 billion years old then some species could be billions years ahead of us in technology.

Post 1

"...the majority of the Earth's water comes from asteroids."

This really doesn't explain why the Earth would have such an abundance of H2O while other planets have virtually none. Are Venus, Mercury and Mars not pelted by comets at roughly the same rate as we?

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