Early Atmosphere and Oceans

In its earliest days, our Earth was a molten ball with no atmosphere and no oceans. The surface was so hot that water and gases couldn't exist as we know them.

Over time, gases began escaping from volcanic eruptions. Additionally, Comets crashing into Earth brought icy materials that, when warmed, turned into gases and water vapor.

Due to these processes, gases like nitrogen, carbon dioxide, hydrogen, and water vapor were present in the early atmosphere.

As the planet cooled, the water vapor in the atmosphere condensed into liquid. This fell as rain for millions of years, forming Earth’s first oceans. Over time, streams carried minerals into these waters, making them salty.

About 2.4 billion years ago, organisms like cyanobacteria, which were capable of producing oxygen through photosynthesis, evolved.

The oxygen they produced gradually filled the atmosphere, leading to the formation of ozone. The ozone layer created a protective shield that blocked harmful solar radiation.

This development paved the way for complex life forms to evolve as we know today.