Artificial superintelligence could indeed significantly accelerate quantum computing development, which would pose a serious threat to Bitcoin's current cryptographic security.

**How ASI could accelerate quantum computing:**

ASI could potentially solve key technical challenges that currently limit quantum computers - like maintaining quantum coherence, reducing error rates, and scaling up qubit counts. It might discover new quantum algorithms, optimize hardware designs, or find novel approaches to quantum error correction that human researchers haven't conceived.

**The Bitcoin threat:**

Bitcoin relies on elliptic curve cryptography (specifically ECDSA) for digital signatures and SHA-256 for proof-of-work. A sufficiently powerful quantum computer running Shor's algorithm could break the elliptic curve cryptography, allowing attackers to derive private keys from public keys and steal bitcoins. The SHA-256 hashing would be less vulnerable but could still be weakened by Grover's algorithm.

**Current estimates and uncertainties:**

Experts generally estimate that breaking Bitcoin's cryptography would require millions of logical qubits, while today's quantum computers have only hundreds of noisy physical qubits. Without ASI, this threat might be decades away. With ASI accelerating development, the timeline could compress dramatically - though it's impossible to predict by how much.

**Potential defenses:**

The Bitcoin network could theoretically upgrade to quantum-resistant cryptographic algorithms before quantum computers become powerful enough to break current encryption. However, this would require broad consensus and careful implementation.

The intersection of ASI and quantum computing represents one of the more concrete ways advanced AI could disrupt existing digital infrastructure.