The Earth has become a vibrant planet due to its abundant liquid water resources.
So, where does the water on Earth come from?
There are two main theories regarding the source of liquid water.
One theory suggests that water originates from the Earth itself. According to this theory, when the Earth was forming, it absorbed various elements, including water components, from the nebular material in space.
Although water existed in the form of vapor in the early high-temperature and high-pressure environment of the Earth, it eventually condensed into rain as the Earth cooled, ultimately forming large bodies of liquid water, constituting the Earth's oceans.
Supporters of this theory believe that underground water resources, especially mantle water, are more abundant than surface water.
Scientists have found a significant amount of trapped hydrogen atoms in Earth's rocks, which can react with quartz to generate water, suggesting that mantle water resources may be 1 to 10 times more abundant than surface water resources.
Another theory is that water comes from space.
This theory suggests that the water on Earth mainly comes from asteroids and comets in space, which brought a significant amount of water to Earth during its early formation.
During the early stages of Earth's formation, there were many small celestial bodies around Earth that frequently collided with it, bringing water to Earth. There is currently insufficient evidence to fully support whether water originates from Earth or space.
However, as Earth evolved, with the establishment of the water cycle and the refinement of the atmospheric system, Earth's water resources have essentially not decreased.
Most of the water on Earth exists in the oceans, evaporating to form clouds, eventually precipitating and returning to the oceans through surface runoff and groundwater flow.
Despite significant human usage of water resources, the total amount of water on Earth remains relatively constant due to the existence of natural water cycling mechanisms.
Although the total amount of water has not decreased, the distribution of water resources may change over time.
Recently, geologists discovered a piece of serpentinite in the western strata of Greenland. Analysis revealed that it formed about 4 billion years ago and required the involvement of a significant amount of seawater.
Therefore, by analyzing the deuterium content within it, scientists could estimate the size of the ocean 4 billion years ago.
Studies suggest that the total amount of seawater in Earth's history has decreased by approximately one-fourth, with this reduced seawater possibly existing on Earth in other forms.
From the early stages of Earth's formation to the present, the existence and circulation of water on Earth have been a complex and intricate process.
Despite the various theories about the origin of Earth's water resources, ongoing research and exploration continue to deepen our understanding of this blue planet, upon which we depend for survival.
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