When viewed from space, Earth appears as a predominantly blue sphere, with those blue areas representing water. In the solar system, Earth is the only celestial body that possesses liquid water. This raises the intriguing question: where does the water on Earth come from?
For a long time, the origin of Earth's water has been a topic of heated debate. One theory suggests that water fell from the sky; another posits that rain and snow are the result of water vapor evaporating from the ground and then returning to the atmosphere. Some scientists have proposed that solar wind played a role in the creation of water, claiming that the water on Earth is a product of solar wind. For instance, Tovili suggested that the total amount of hydrogen absorbed by Earth from solar wind is approximately 1.70×10^23 grams, which combines with oxygen on Earth to produce a significant amount of water. However, as research into volcanic phenomena deepened, this viewpoint was challenged. It was discovered that the water associated with volcanic activity is part of Earth's existing water cycle and is not “new water” released from deep within the planet.
Additionally, scientist Klein analyzed tritium in hot water associated with volcanic activity around the world, proving that it is identical to local surface water, thus confirming that it is groundwater that has seeped underground and, under volcanic heat, has re-emerged as water vapor. Moreover, researchers from the University of Iowa, including Frank, proposed a compelling new theory: comets composed of ice in space are the source of Earth's water. They found that water vapor molecules in the atmosphere can break down into hydrogen and oxygen atoms under the influence of solar ultraviolet radiation, with hydrogen atoms drifting away into space. They also discovered that thousands of images of Earth's atmospheric ultraviolet radiation sent back from satellites show small black spots, which are composed of tiny, invisible ice comets that collide with Earth's atmosphere and melt into water vapor. These small comets frequently enter the atmosphere, providing a continuous source of water for Earth.
