Читать книгу Oceans For Dummies - Joseph Kraynak - Страница 43

The prevailing theory is that the water and/or the chemicals needed to make water were already here when Earth was formed. In other words, Earth formed as a “wet planet.” How planets are formed is also a subject of debate, but generally speaking, they form when particles of dust and gas clump together. In its early days, our solar system was a cloud of dust and gas (or clumps of dust and gas). Gravity caused the matter to collapse in on itself as it began to spin, forming the Sun at the center and the planets around it.

According to this theory, the ocean was formed when water (in the form of vapor) slowly escaped from Earth’s hot molten interior into the atmosphere surrounding the cooling planet. This degassing, as it’s called, occurred over millions of years. As the planet cooled to below the boiling point of water, the vapor slowly condensed into clouds and rain began to fall for centuries or even millennia. At some point, estimated at between 4.4 to 3.8 billion years ago, enough water had been wrung from the sky to create the primeval ocean.