Quantum computers to Bitcoin's encryption, particularly through Shor's algorithm, which could break public-key cryptography like ECDSA. However, current quantum computers are not powerful enough to execute this threat. Bitcoin also uses SHA-256 hashing, which is less vulnerable to quantum attacks. The Bitcoin community is actively researching post-quantum cryptography and could implement a hard fork to enhance security if necessary. 
While quantum threats are a future concern, they are not immediate, so there's no need for panic selling Bitcoin at this time. 
Ongoing research and preparation are important for the future.