Nic Carter, a partner at Castle Island Ventures, has raised concerns about Bitcoin's vulnerability to quantum computing, predicting that a cryptographically relevant quantum computer (CRQC) could emerge by 2035. Carter points to the rapid advancements in quantum computing and significant investments from both private and public sectors as indicators of this timeline. He warns that Bitcoin could become a target for quantum attacks, potentially leading to significant disruptions in ownership and price. Carter emphasizes the need for the Bitcoin community to proactively address these vulnerabilities, as future upgrades may become challenging to implement in time.