Did you know rock salt can hold air pockets? Did you also know that, after carefully crushing rock salt from 815 million years ago, some scientists believe that the level of oxygen in the air during that time period was 10.9%, way higher than currently believed. Until now, the oxygen levels were anticipated to reach that point only 600 million years ago, a two hundred million years difference! That's a lot of presidential terms.

Source: https://www.sciencenews.org/article/ancient-air-bubbles-could-revise-history-earth%E2%80%99s-oxygen

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