1. How does Earth's modern atmosphere compare to its primordial atmosphere? Outgassing has been instrumental in shaping Earth's modern atmosphere, but not the primordial atmosphere. Interactions between the geosphere and biosphere shaped both the primordial atmosphere and Earth's modern atmosphere. Water vapor was likely the main component of the primordial atmosphere, whereas nitrogen is the main component of Earth's modern atmosphere. The primordial atmosphere likely contained much more carbon dioxide than Earth's modern atmosphere.

The primordial atmosphere of Earth was a wild and rocky place, dominated by volcanic outgassing. It was rich in water vapor, carbon dioxide, and other gases but lacked the oxygen we breathe today. Over millions of years, as the planet cooled and the first oceans formed, water vapor condensed and fell as rain, leading to the gradual removal of CO2 and the emergence of life which began to produce oxygen through photosynthesis. Now, here’s a fun twist: imagine if the primordial atmosphere had a personality! It would be a wild teenager brimming with chaos - way too much carbon dioxide and no oxygen, living off volcanic fumes. In contrast, Earth's modern atmosphere is more like a calm adult, composed largely of nitrogen and oxygen, nurtured by the biosphere and its delicate balance of various gases. Welcome to the mellow after-party of Earth’s atmospheric evolution!