Earth’s material would have contained a significant amount of water, according to scientists[23]. Water molecules would have been able to escape Earth’s gravity more easily when it was less massive when it was formed. The term for this is atmospheric escape.

Earth may have had magma oceans when the planet formed. According to current theories, an early atmosphere of carbon dioxide, nitrogen, and water vapor was produced by outgassing, volcanic activity, and meteor impact. It is thought that the atmosphere and the gases accumulated over many millions of years. After the surface of Earth had significantly cooled, water vapor would have condensed over time, forming the first oceans. Due to their high iron content, the early oceans may have appeared green and were significantly hotter than they are today.

The duration of Earth’s existence of liquid water is constrained by geological evidence. The Isua Greenstone Belt’s recovery of a piece of pillow basalt, a type of rock formed during an underwater eruption, provides evidence that water existed on Earth 3.8 billion years ago. One study dates rocks in the Nuvvuagittuq Greenstone Belt in Quebec, Canada, at 3.8 billion years old and another at 4.28 billion years old, indicating that water was present at these ages.

Any geological evidence of earlier oceans either hasn’t been found or has been destroyed by geological processes like crustal recycling. However, more recently, in August 2020, researchers published a report claiming that the Earth may have always had enough water to fill its oceans. When the newly formed Sun had only 70% of its current luminosity, atmospheric greenhouse gases prevented the oceans from freezing, according to this model. Earth’s magnetic field was established by 3.5 Ga, preventing the solar wind from removing the atmosphere.