(Roughly) Daily

Ethan Siegel reminds us that the world– the living world– almost did end in ice…

… one event came closer than any other to bringing an end to life on Earth: a catastrophe known as either the Great Oxidation Event or the Great Oxygenation Event. Oxygen, one of the hallmark characteristics of our living Earth, was a tremendous destructive force when it first arrived in any sort of meaningful abundance some ~2 billion years after Earth first took shape. The slow alteration of our atmosphere by the gradual addition of oxygen proved to be fatal to the most common types of organism that were present on Earth at the time. For several hundred million years, the Earth entered a horrific ice age which froze the entire surface: known today as a Snowball Earth scenario. This disaster almost ended life on Earth entirely. Here’s the story of our planet’s near-death, culminating in life’s ultimate survival story…

For roughly 300 million years, the Earth was frozen: “What was it like when oxygen killed almost all life on Earth?” from @StartsWithABang in @bigthink. Eminently worth reading in full.

* Robert Frost, “Fire and Ice“

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As we contemplate change, we might send chilly birthday greetings to Raoul Pictet; he was born on this date in 1846. Remembered as a pioneer in cryogenics, Pictet was a Swiss chemist who spent much of his career trying to produce very low temperatures (in order to produce ice for refrigeration)– which led him to the creation of liquid oxygen in 1877 (for which he’s credited as co-discoverer, as French scientist Louis-Paul Cailletet, working completely separately, also produced liquid oxygen that year).

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