Years ago, during a long Pacific flight, the author Bill Bryson experienced a moment of realization about his ignorance regarding Earth, the only planet he would ever inhabit. Gazing at the moonlit ocean, he felt a pressing need to understand fundamental aspects of the planet he called home. He reflected on his lack of knowledge about simple phenomena, such as the reasons behind the salinity of oceans compared to the freshwater of the Great Lakes.

This contemplation led Bryson to question other crucial matters concerning the oceans, particularly whether their salinity was changing over time and if such changes warranted concern. His reflections highlight a broader issue about human understanding of planetary science and the importance of being informed about the environment we live in.