From the perspective of physics, it’s worth emphasizing how surprising this all is. Energy is the coin that pays for all comings and goings throughout the cosmos, a coin minted in a wide range of currencies and earned through an even wider range of callings. One currency is nuclear energy, generated by fission and fusion among a wealth of atomic species; electromagnetic energy is another, generated by pushes and pulls among a wealth of charged particles; gravitational energy is another still, generated by interactions among a wealth of massive bodies. And yet of all the innumerable processes,
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