Bitcoin mining is like a lottery: miners sift through billions of numbers to find one lucky winner. A regular computer does this blindly, burning electricity. A quantum computer could sort through possibilities faster, like finding a needle in a haystack by shaking the whole stack at once.
The authors of a new study calculated what such a quantum "shaker" would actually cost. They accounted for everything: the qubits themselves, cooling systems, manufacturing plants, and logistics. The result is sobering. For the easiest task, finding an incomplete key, you'd need around 100 million qubits and 10 gigawatts of power. That's like ten large nuclear power plants.
But the real Bitcoin network is far more complex. To outpace all miners on the planet at current difficulty, a quantum computer would need 10 to the 23rd power qubits and 10 to the 25th power watts. That's comparable to the radiation of an entire star. Humanity today produces billions of times less.
Quantum mining turns out to be an economic absurdity. Even if engineers built a perfect quantum computer, the electricity bill would make mining unprofitable. Bitcoin will remain in the hands of conventional farms for the foreseeable future, and the quantum threat applies only to signatures, not mining.
For a quantum computer to outpace all Bitcoin miners, it would need more energy than Earth receives from the Sun in a year.
The idea of using stellar energy for computation evokes 'The Matrix', where machines enslaved humans for electricity.