When Michio Kaku was eight years old he heard that a great scientist had died, and when he looked in the newspaper there was an image he found impossible to forget.
It was a picture of Einstein’s desk, and on it there was an open notebook. Its pages revealed that the man some judge to be the smartest human being who ever lived had been working on a problem that even he had been unable to solve.
The young Kaku was overwhelmed. “What could possibly be so hard that even the great Einstein could not solve it?”
您已阅读12%（509字），剩余88%（3595字）包含更多重要信息，订阅以继续探索完整内容，并享受更多专属服务。