chemistry

Physics & Space

Earth History & Geology

• Great Oxidation EventFor much of early Earth history, the atmosphere contained almost no free oxygen. Photosynthetic microbes were producing oxygen long before it accumulated in the air, because oxygen was rapidly consumed by sinks — reduced volcanic gases, minerals, and especially dissolved iron in the oceans.
• Prebiotic Chemistry: Ingredients Are Not Yet a SystemLife uses carbon compounds, but “organic” does not mean “made by an organism.” The deeper problem is how nonliving chemistry could repeatedly make useful products faster than dilution, decomposition and side reactions removed them.