Astronomers Sean Raymond (University of Bordeaux, France) and Andre Isidoro (University of São Paulo Julio de Mesquita Filho, Brazil) described a possible mechanism for how water got to Earth. Their research was published in the journal Icarus, available on the website arXiv.org, and the first author spoke about it on his blog.
Scientists believe that water on Earth and celestial bodies from the asteroid belt between the orbits of Mars and Jupiter has a common origin, primarily associated with the formation of gas giants in the Solar System.
Oceans cover three-quarters of the Earth, but the water on the surface accounts for only one four-thousandth of the planet's total mass. There is water both in the mantle (in the form of hydrated rocks) and in the Earth's core. How much there is is unknown, probably ten times more than on the surface.
In general, there is little water on Earth, and there is also some on the Moon, Mercury, Venus and Mars. Perhaps Venus and Mars once had more water. The main reservoir of water within the orbit of Jupiter is the asteroid belt.
In the inner part of the main belt, within 2−2.3 astronomical units from the Sun, asteroids of class S (rocky) predominate, in the outer part - class C (carbonaceous). There are other asteroids, but not so massive. Class C asteroids contain more water than class S—about ten percent (by mass).
The origin of water can be determined by conducting an isotopic analysis of the hydrogen contained in the water of various celestial bodies. In addition to protium, hydrogen with a nucleus of one proton, deuterium (with a proton and a neutron) and very rarely tritium (with a proton and two neutrons) are found in nature.
NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles Jupiter
Isotope analysis reveals several features. The Sun and gas giants have a ratio of deuterium to tritium that is one to two orders of magnitude less than that of the Earth. But for class C asteroids this figure is almost the same as for our planet. This indicates a common origin of water.
Comets in the Oort cloud have a ratio of deuterium to protium that is approximately twice that of Earth. There are three comets within the orbit of Jupiter, for which this parameter is close to that of Earth, but there is also one comet where this parameter is 3.5 times higher. All this may mean that the water on comets has different origins and only part of it was formed in the same way as on Earth.
Ceres
Planets form around young stars in giant disks of gas and dust. Closer to the star it is too hot, so planets rich in silicon and iron appear there. Farther away from the star it is colder, where celestial bodies can also form from water ice. The Earth arose in that part of the protoplanetary disk where rocky celestial bodies were born, without water. This means that she came to the planet from outside.
On the other hand, S and C class asteroids are too different for them to form next to each other. In addition, the boundary beyond which icy celestial bodies formed constantly moved during the evolution of the Solar System, and Jupiter played a decisive role in this.
Jupiter and Saturn are believed to have formed in two stages. At first they were solid celestial bodies, several times heavier than the modern Earth, and then began to capture gas from the protoplanetary disk. At this stage, the mass and size of the planets increase sharply, the giants clear space for themselves in the protoplanetary disk.
Large Jupiter and Saturn were then surrounded by small planetesimals - the predecessors of protoplanets. As Jupiter and Saturn grew, the orbits of the planetesimals stretched, crossing the inner Solar System and moving away from the star. But Jupiter and Saturn still attracted gas from the protoplanetary disk, as a result of which, as the simulation showed, the orbits of the planetesimals were corrected by Jupiter and moved into the region of the modern asteroid belt.
Saturn arose later than Jupiter, and its formation led to a new migration of planetesimals, although not as significant. The main conclusion of the researchers is that class C asteroids appeared in the belt from the orbits of the gas giants after Jupiter and Saturn completed their formation (although some planetesimals could reach the orbit of Neptune).
According to scientists, water came to our planet during the formation of the asteroid belt thanks to planetesimals of a certain type (namely, class C asteroids) with highly eccentric (elongated) and unstable orbits that intersected the trajectory of the Earth. Hydrogen isotope analysis is the main confirmation of this.
The delivery of water to Earth was almost completed with the formation of Jupiter and Saturn and the disappearance of the protoplanetary disk. Thus, the popular hypothesis that explains the small size of Mars by the migration of Jupiter deeper into the Solar System correlates with the mechanism of enrichment of Earth with water. The appearance of water, the most important source of life on Earth, in the inner Solar System (both on rocky planets and in the asteroid belt) turns out to be simply a side effect of the growth of Jupiter and Saturn.
Earth is often called the "Blue Planet" not only because of the composition of the atmosphere, which gives the planet a delicate bluish tint, but also because of the oceans that cover more than 70% of the earth's surface. It was in the oceans that life appeared, and therefore scientists are interested in the question of when and how water appeared on Earth.
Previously, it was believed that oceans formed on our planet when it was already quite “adult,” but recent research conducted at the Woods Hall Oceanographic Institution (USA) proves that there has always been water on Earth.
According to the previously existing theory, planets are formed dry, since their formation is associated with high-energy and impact processes. If there are water molecules on “young” planets, they evaporate until the planet completes the formation stage. Water reaches planetary bodies after their formation is completed, after the fall of comets and “wet” asteroids consisting of frozen water and gases. According to this theory, all the water that exists on Earth today came to the planet millions of years after its birth.
In their research, scientists from the Woods Hall Institute turned to carbonaceous chondrites, which are also a potential source of planetary water. The simplest meteorites of this substance were formed in the flow of dust, ice and gases that gave birth to the Sun, long before the appearance of other themes in our star system.
According to Woods Hall employee Sune Nielsen, carbonaceous-chondrite meteorites are the most common objects in the solar system. They contain a fairly large number of water molecules and were previously considered the main source of water on our planet.
To find out when and how water appeared on Earth, scientists measured the ratio of stable isotopes of hydrogen, normal with one neutron, and deuterium with two. In different areas of our star system, this ratio differs. The researchers further concluded that comparing the proportion of carbonaceous chondrites in an object that formed at the same time as our planet could help answer the question of when and how water appeared on Earth.
The 4-Vesta asteroids were formed in the same area as the Earth and at the same time as it. They are covered by a basaltic layer of hardened lava. These celestial bodies are the oldest reservoirs of hydrogen in our system, as they appeared 14 million years after the birth of the Solar System. At this time, our planet was at the stage of its formation. Thanks to all these characteristics, 4-Vesta became ideal objects for determining how water appeared on Earth and when.
After analyzing the samples collected by NASA, scientists came to the conclusion: they contain the same ratio of hydrogen and nitrogen isotopes as in carbonaceous chondrites and in the composition of the Earth. This makes them the most likely source of water molecules in the solar system. Consequently, water resources appeared on Earth simultaneously with solid rocks. Our planet was born in water.
During the research, scientists did not take into account the water that entered the planet later, since this was not necessary. On Earth in its “childhood years” there were already enough water resources for the birth of oceans. In combination with other conditions at the dawn of the formation of our planet, this led to the birth of life on Earth. It is possible that on other planetary bodies there was enough moisture for the emergence of living beings, but climate change later made them uninhabitable.
The water on this comet supposedly had the same isotopic composition as water on Earth. Scientists from SOHO, a joint project between NASA and the European Space Agency (ESA), have calculated the approximate volume of water on the comet. The comet's explosion released a cloud of released hydrogen.
Comet LINEAR, which contained large amounts of water, exploded in August 2000, as seen by the Hubble Telescope. Photo: NASA
"The idea that comets seeded life on Earth by bringing water and basic molecular constituents is a hotly debated topic, and this is the first time we've found a comet that could actually do this," says Michael Mumma of NASA's Goddard Flight Center. .
Water has been found in other parts of space, but, unlike the water on this comet, its isotopic composition is different from that of Earth.
In 2011, astronomers discovered the largest and most distant accumulation of water in the Universe. It is 140 trillion times the amount of water in the world's oceans. It surrounded a quasar, a supermassive black hole located 12 billion light years from Earth.
A quasar similar in type to APM 08279+5255, where scientists discovered a huge amount of water. Illustration: NASA/ESA
“The environment around this quasar is unique in that it produces large amounts of water,” Matt Bradforle, a scientist at NASA's Jet Propulsion Laboratory, said in a NASA news release. “This is further evidence that water is distributed throughout the universe.”
In addition, in 2011, astronomers discovered oceans of water around the young star. This solar system, orbiting a star, is located 175 light years away. The large amount of water suggests that planets covered in water like Earth are common throughout the universe, NASA says.
An icy disk forming around a young star called TW Hydrae, located 175 light-years away in the constellation Hydra South. Illustration: NASA/JPL-Caltech
Since the human body is mostly made up of water, figuring out the origins of the earth's water will help us understand where the matter that makes up our bodies came from.
Would you install an application on your phone to read articles from the epochtimes website?
The life of all life on Earth depends on the much-needed clear liquid, but no one knows for sure where water comes from and how it appeared on our planet. Some hope is inspired by recent findings confirming the presence of water in one form or another on many other celestial bodies. This gives us a little hope that we are not alone in the Universe.
Why does a person need water?
The daily water requirement of an adult is ~2 liters:
- Liquid is necessary for the normal functioning of metabolic processes.
- Partially thanks to water, blood flow and fluid reserves in cells and intercellular space are replenished.
- It is necessary to regulate electrolyte balance. Its violations can lead to the cessation of nerve impulses.
- The average person cannot live more than a few days without fluid.
All this makes us think that there is not much drinkable water on the planet.
Most of it is sea water, the presence of salt in its composition eliminates the possibility of quenching thirst. And this if you consider that life-giving not only to people, but also to all representatives of flora and fauna.
Where did the water come from?
According to its chemical composition, water is combination of oxygen and hydrogen . There are a huge number of hydrogen atoms in the Universe, because all the stars are its “forges”. With oxygen it’s a little more complicated, but specifically on our planet it was present almost from the first days. All that remains is to wait for the two elements to combine into something unique and completely new, but when there are billions of years ahead, you can wait a little.
Scientists still cannot understand the nature of the heat capacity and heat transfer of water. According to all the laws of chemistry, this substance should have had completely different characteristics.
Maybe it’s a matter of the level of our knowledge, or maybe the situation is much more interesting. But today we can confidently say the following about water:
- Water is found not only on Earth, but also in many other corners of the Universe.
- It was formed as a result of the combination of hydrogen and oxygen in proportions of 2 to 1.
- Water is found both on planets and on asteroids and comets.
- It is even present in outer space. Most often found in solid form.
Where does water come from on earth?
Regarding the appearance of water on our home planet, there are two opposing theories:
|
Terrestrial origin of water |
Extraterrestrial origin of water |
|
It appeared due to the contact of hydrogen and oxygen released by the magma. |
The water was brought in as a result of bombardment by millions of comets and asteroids. |
|
Formed during the first few hundred million years of the planet's formation. |
It arose due to the attraction of fine dust containing water scattered in space. |
|
The existence and circulation of water was maintained due to changes in orbit and uneven illumination. |
All this happened after the formation of the Earth was completed, which may explain the tectonic features. |
|
Confirmed by the latest research. |
At the moment there is no confirmation, only hypotheses. |
No one can put a final point in this dispute; our ideas about the world around us are still largely fragmented. But it is the first theory that looks most promising.
Terrestrial origin of water
Today we know for sure that the Earth is not unique in terms of the presence of water. In the same comets and meteorites, H2O must have been formed somehow. This means that a mechanism for the production of water in the Universe exists, which adds a point to the treasury of supporters of the theory of the terrestrial origin of water.
Humanity has safely explored Moon And I didn't find any traces of water there. And this is on the nearest satellite, which, by astronomical standards, is “a stone’s throw away.” Some selective comets and meteorites brought water to Earth, but not to the Moon. It can be stated that the moon has no atmosphere of its own, but the almost complete absence of an atmosphere on Mars did not prevent the existence of entire “ice caps” at its poles.
What can we say about the number of celestial bodies necessary to “fill” the Earth with all the water that is now on it. Moreover, this in no way explains why most of the water is salty and only a small proportion is fresh ( According to statistics, 3% fresh and 97% salty).
But if H2O was formed on Earth as a result of a chain of chemical reactions, a couple of options for answering this question can be considered.
Where does the water in the water supply come from?
But most often we are concerned with more pressing problems than the nature of the origin of water. Much more interesting How does it get into our taps? and then “migrates” to teapots and pots.
According to the developed hygiene standards, there are:
- A reservoir from which water is drawn for the needs of the population.
- A number of water intake structures that collect and filter liquid.
- Extensive water supply system. The same pipes through which liquid flows into our homes.
Water quality is regularly monitored, observing GOST and other standards. That's just The quality of water pipes leaves much to be desired.
Even if the water “at the entrance” to the system was perfectly clean, at the “output” it is not always suitable for consumption. That's why It is better to filter and boil tap water.
Some people are interested in settling, freezing and other complex filtration systems. If we were somewhere in Nigeria, such precautions would have a right to exist. But in the post-Soviet space, with water from the pipeline, everything is not so bad.
Where did the water come from?
The existence of water on our planet is ensured by:
- Complex climate change.
- Different amounts of heat that the surface receives.
- The process of evaporation and condensation of liquid.
- The presence of the Sun, which provided an influx of hydrogen.
- The release of oxygen by magma and its fusion with hydrogen.
If we look at the issue from a slightly down-to-earth point of view:
- Water enters apartments and houses through pipes.
- In them it is given under pressure from water intake structures.
- This is where the water is filtered.
- And it is taken from the nearest body of water - river, lake, reservoir.
But it is important not only to know where the water comes from, but also to maintain the normal water-salt balance of your own body.
Some questions are actually more complicated than they seem at first glance. From a scientific point of view, not many people can explain where water comes from. Now you know that this liquid did not just come from a tap.
Video about the origin of water on Earth
Scientists are still arguing about the appearance of water on Earth. One friend started looking for hypotheses. I found six of them. There is no agreement in this world! Where does water on Earth come from - answer options.
Hypotheses about the origin of water on Earth
First hypothesis. Hot origin of the Earth
It is believed that the Earth was once a molten ball of fire, which, radiating heat into space, gradually cooled. The primordial crust appeared, chemical compounds of elements arose, and among them the compound of hydrogen and oxygen, or, more simply, water.
The space around the Earth became increasingly filled with gases that continuously erupted from cracks in the cooling crust. As the vapor cooled, it formed a cloud cover that tightly enveloped our planet. When the temperature in the gas envelope dropped so much that the moisture contained in the clouds turned into water, the first rains fell.
Millennium after millennium the rains fell. They became the source of water that gradually filled the oceanic depressions and formed the World Ocean.
Second hypothesis. Cold Origin of the Earth
The Earth was cold, and then it began to warm up. The heating caused volcanic activity. Lava erupted by volcanoes carried water vapor to the surface of the planet. Some of the vapor, condensing, filled the oceanic depressions, and some formed the atmosphere. As has now been confirmed, the main arena of volcanic activity in the early stages of the Earth's evolution was indeed the bottom of modern oceans.
According to this hypothesis, the water was contained already in that primary matter, from which our Earth was formed. Confirmation of this possibility is the presence of water in meteorites falling to Earth. In “heavenly stones” it is up to 0.5%. At first glance, a tiny amount. How unconvincing!
Third hypothesis
The third hypothesis again comes from the “cold” origin of the Earth with its subsequent heating.
At some stage of heating in the Earth's mantle at depths of 50-70 km, water vapor began to arise from hydrogen and oxygen ions. However, the high temperature of the mantle did not allow it to enter into chemical compounds with the mantle matter.
Under the influence of enormous pressure, steam was squeezed into the upper layers of the mantle, and then into the Earth’s crust. In the crust, lower temperatures stimulated chemical reactions between minerals and water, as a result of loosening the rocks, cracks and voids formed, which were immediately filled with free water. Under the influence of water pressure, the cracks split, turned into faults, and water rushed through them to the surface. This is how the primary oceans arose.
However, the activity of water in the Earth's crust did not end there. Hot water dissolved acids and alkalis quite easily. This “hellish mixture” corroded everything and everyone around, turning into a kind of brine, which gave the sea water its inherent salinity to this day.
Millennia replaced each other. The brine inexorably spread wider and deeper under the granite foundations of the continents. It was not given to him to penetrate into the granite itself. The porous structure of granite, like a thin filter, retained suspended matter. The “filter” became clogged, and when clogged, it began to play the role of a screen, blocking the path of water.
If all this took place, then under the continents at a depth of 12-20 km there are oceans of compressed water saturated with dissolved salts and metals. It is quite possible that such oceans also spread under the many kilometers of basalt bottom of the terrestrial oceans.
This hypothesis is supported by a sharp increase in the speed of seismic waves at a depth of 15-20 km, i.e. exactly where the supposed interface between granite and the brine surface should lie, the boundary of a sharp change in the physical and chemical properties of the substance.
This hypothesis is also confirmed by the so-called continental drift. The granite masses of the continents are moving. They “float”, although their speed of movement is only a few centimeters per century. Why not assume that the oceans of brines act as a kind of film under the “bottoms” of the continents, like a film of oil in a bearing between the axle and the shaft.
If brines exist, then in the future humanity will probably use them as the richest liquid ore in which the most valuable elements and their compounds are dissolved.
The fourth hypothesis of the English astrophysicist Hoyle
Its essence is this: the condensation of the protoplanetary cloud surrounding our proto-Sun proceeded unequally at different distances from the Sun. The farther from it, the lower the temperature of the cloud. Closer to the Sun, say, metals could condense as more refractory substances. And where the orbits of Uranus, Neptune and Pluto pass, according to Hoyle’s calculations, the temperature was approximately 350 K, which is already sufficient for the condensation of water vapor. 
It is this circumstance that can explain the “watery” nature of Uranus, Neptune and Pluto, formed in the process of merging particles of ice and snow. The “water” nature of these planets is confirmed by the latest astronomical observations.
However, during the formation of the outer planets, there was a gravitational “pushing” of ice blocks into the region of the inner planets. Those blocks that were of sufficient size, without having time to completely evaporate from the sun’s rays, reached the Earth and fell on it in the form of a kind of icy “rain.” Obviously, such “rains” were more abundant on Mars and very scarce on Venus.
Hoyle's calculations confirm the possibility of the formation of Earth's oceans from freezing rain, which took only a few million years.
Fifth hypothesis
It, like the fourth, assumes a purely cosmic origin of water, but from other sources. The fact is that a shower of electrically charged particles is continuously falling onto the Earth from the depths of space. And among these particles, a fair proportion are protons - the nuclei of hydrogen atoms. Penetrating the upper layers of the atmosphere, protons capture electrons and turn into hydrogen atoms, which immediately react with atmospheric oxygen. Water molecules are formed. Calculations have shown that a cosmic source of this kind is capable of producing almost 1.5 tons of water per year, and this water reaches the earth's surface in the form of precipitation.
One and a half tons... By global standards - an insignificant amount. But it should be borne in mind that the formation of such cosmic water began simultaneously with the emergence of the planet, i.e., more than 4 billion years ago.
Sixth hypothesis
As scientists have established, approximately 250 million years ago there was a single continent on Earth. Then, for unknown reasons, it cracked, and its parts began to creep apart, “floating” away from each other.
Evidence of the existence of a once single continent is not only the similarity of coastlines, but also the similarity of flora and fauna, the similarity of the geological structures of the coasts. In short, few people now doubt the unity of the Earth's continents in the past. Another thing causes bewilderment: how can continental blocks, like giant “icebergs,” float away from each other if their roots go tens of kilometers deep? And what sets them in motion?
Research in recent years has confirmed: yes, the continents “float”, the distance between them is continuously increasing. The movement of continents is brilliantly explained by the expanding Earth hypothesis. The hypothesis states: initially the Earth had a radius half as large as it is now. The continents, then merged together, encircled the planet. Oceans did not exist. And then, at the border of the Proterozoic and Mesozoic (250-300 million years ago), the Earth began to expand. The single continent gave way to cracks, which, when filled with water, turned into oceans. And from then to our time, the radius of the Earth has doubled!
The invention of atomic clocks made it possible to determine with absolute accuracy the longitude and latitude of earthly objects from the starry sky. Measurements have shown that our planet... continues to expand!
Europe, for example, is expanding. Moscow and Leningrad are “swimming” east at a speed of 1 cm per year. And Hamburg, located in the center of Europe, remains in place.
The speed of expansion of the European continent is enormous. Indeed, in just 20 million years (an insignificant period for a geological epoch), as a result of such movement, a bowl of the future ocean 4000 km wide could form.
However, until now, proponents of the expanding Earth hypothesis did not have any arguments with which they could explain why the Earth is expanding.
Now there are such arguments.
Let us remember first of all (and we will return to this later) that the Universe consists of 98% hydrogen, i.e., the element that gives birth to water. Our Earth is 98% hydrogen. It came to us along with those particles of cold cosmic dust from which all the planets of the solar system were formed. And among these particles there were also metal atoms.
This is where we come across an interesting phenomenon. It turns out that metals are capable of absorbing huge amounts of hydrogen - tens, hundreds and even thousands of volumes per volume. Further: the more hydrogen a metal absorbs (or attaches), the denser it becomes, i.e., it decreases more and more in volume. Yes, we didn’t make a reservation - it’s decreasing. Thus, alkali metals, by adding hydrogen, decrease in volume by 1.5 times already at atmospheric pressure. As for other metals (for example, iron and nickel, of which, according to scientists, the Earth’s core is composed), then at normal atmospheric pressure (105 Pa) the decrease in volume is very insignificant.
However, as the dust cloud compacted, its gravitational compression occurred, and the pressure inside the proto-Earth increased. Accordingly, the degree of hydrogen absorption by metals of the iron group also increased. Compression generated the antipode of pressure - heating.
And since the central regions of the formed planet were subjected to the greatest compression, the temperature there also increased more rapidly.
And at some stage of heating, when the temperature in the Earth’s core reached a certain critical value (the transition of quantitative growth to a new qualitative state!), the reverse process began - the release of hydrogen from metals.
The disintegration of metal-hydrogen compounds, i.e., the restoration of metal structures, caused a sharp increase in the volume of matter in the Earth's core. The expansion of the metal core manifested itself with such force that the mantle and crust of the planet, unable to withstand it, cracked.
Thus, the degassing of hydrogen was accompanied by the expansion of the Earth. Meanwhile, hydrogen, penetrating the enormous thickness of the planet, captured oxygen atoms along the way, and water vapor was already escaping to its surface. Condensing, the water filled the cracks in the crust. Oceans gradually formed.
So, six hypotheses of the origin of earthly water. Over time, it will become clear which of them is true. Perhaps all six will turn out to be true, each to some extent. In the meantime, the question “Where did water come from on Earth?” remains open.