Their demon is another atomic nucleus, which interacts with the first as the demon would.

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Radioactivity is measured in Becquerels, which convey the disintegration of an atomic nucleus per second.

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Other ideas include building a detector to see if the spin of an atomic nucleus can be measured, or using the technique as an ultrasensitive antenna.

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This theory holds that in its early history, the observable Universe underwent a period of exponential expansion, doubling in size many dozens of times, growing our observiball a tiny fraction of the size of an atomic nucleus to that of, say, a beach ball.

BBC: The observable Universe and beyond