Scientists have been trying to understand how the oceans on the earth formed and what geological and atmospheric processes were associated with their emergence and development. Unfortunately, despite the immense scientific progress achieved for the past century, people know surprisingly little about how the oceans formed, mainly because this process occurred about four-six billions of years ago. There are two major explanations suggested by the researchers. The first claims that water was locked up in dust and rocks that formed this planet. As a result of complex geological processes, this water was released and formed the oceans in the way we know them today. In other words, the theory suggests that water was supplied to the planet prior to its formation (Genda, 2016).

The second theory suggests that water was delivered to the earth by water-rich meteorites or comets (European Space Agency, 2014; Sarafian et al., 2014). Recent research conducted by NASA showed that comets are made of rock, ice, and other frozen chemicals, which allows suggesting that these unique formations might have brought water to this planet billions of years ago as a result of massive collisions (Bell & Moullet, 2019). Convincing evidence supports this theory, as the composition of water found on Comets Hyakutake and Halley is very similar to the composition of water found in our oceans.

Oceans might have formed due to the combination of the above processes. Water could be derived both from the rocky body of the planet and comets and meteorites that collided with it at the early stages of its formation. There is still no definite answer, so research should continue. One of the ways to learn more about the process of water formation on earth is to explore the water on other planets such as Mars or Venera, as this information can be valuable for understanding the complex biochemical, geological, and atmospheric processes occurring in the process of planet formation.

References
• Bell, K., & Moullet, A. (2019). Comet provides new clues to origins of Earth’s oceans. NASA. Retrieved from https://www.nasa.gov/feature/comet-provides-new-clues-to-origins-of-earth-s-oceans
• European Space Agency (2014). Rosetta fuels debate on origins of earth’s oceans. Retrieved from https://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_fuels_debate_on_origin_of_Earth_s_oceans
• Genda, H. (2016). Origin of Earth’s oceans: An assessment of the total amount, history and supply of water. Geochemical Journal, 50, 27-42.
• Sarafian, A.R., Nielsen, S.G., Marschall, H.R., McCubbin, F.M., & Monteleone, B.D. (2014). Early accretion of water in the inner solar system from a carbonaceous chondrite–like source. Science, 346(6209), 623-626. doi:10.1126/science.1256717