Google achieves a major quantum computing breakthrough, raising new questions about Bitcoin’s long-term security. What Google did? Google demonstrated “magic state cultivation” on its Willow chip, reducing quantum errors by 40x and achieving 99.99% fidelity. Magic states are essential for running complex quantum programs, but producing them has been a major bottleneck for over 20 years. How does this impact Bitcoin? Fewer qubits needed: Google estimates that breaking Bitcoin’s cryptography could require fewer than 500,000 physical qubits, down from earlier estimates in the millions. Current gap remains huge: Google’s Willow chip has 105 physical qubits, and IBM’s Condor has 1,121. Physical vs. logical qubits: Quantum computers need error correction to perform reliable calculations. Google estimates its attack would require around 1,200 to 1,450 logical qubits, each built from many physical qubits. Where we stand: QuEra has reported demonstrations involving up to 96 logical qubits, still well below the estimated requirement for the attack. IBM’s ambitious roadmap: IBM targets 200 logical qubits by 2029 and 2,000 by 2033. These are planned milestones, not guaranteed delivery dates. Google’s own deadline: Google aims to transition to quantum-safe cryptography by 2029, highlighting the need to prepare before quantum computers become a real threat. So Bitcoin isn’t in immediate danger, but developers will need to prepare for a future where quantum computers could threaten its cryptography.