How Much Information Can Earth Hold?

What is the information storage capacity of Earth, and how full is it today? The answer tells us surprising things about the growth of order in the universe

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In 2002 Seth Lloyd, a professor of quantum computing at the Massachusetts Institute of Technology, published a formula estimating the number of bits that could fit in the universe. A “bit” is a fundamental unit of information that represents the answer to a yes or no question. A computer stores bits in a transistor, but a bit can also be encoded in the state of a physical particle, such as the spin of an electron. Lloyd's formula exploited the physicality of information to estimate the rate at which physical systems can process and record information as a function of Planck's constant (an unimaginably tiny unit that is fundamental to quantum mechanics), the speed of light and the age of the universe. Lloyd concluded that our universe could fit a whopping 1090 bits, or a trillion trillion trillion trillion trillion trillion trillion megabits.

Lloyd developed his formula because his work on quantum computers, which use single atoms to encode information and perform computations, had him thinking about the universe in terms of bits that live in atoms. He performed a thought experiment, asking himself: What is the largest computer that could ever be built? The answer: one that would employ every atom in the universe. That computer could store 1090 bits.

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