Strings Outside the Universe

The clock on the wall was quietly ticking.

An hour ago, Frank Wilczek was sitting with perfect posture, staring at the image on the computer screen. He sat there motionlessly.

Suddenly, his office door opened.

Professor Wilczek saw Witten enter his office. He finally raised his head by an inch. However, when he was about to speak, Witten spoke first.

"I know you want to ask me what Professor Lu thinks, but I'm afraid I will disappoint you. Except for a conjecture about an extra dimension, he didn't reveal anything to me."

When Wilczek heard an unexpected word, he frowned.

"Extra dimension?"

An extra physical dimension was not a new concept. All dimensions derived by Einstein's relativity equations could be called extra dimensions.

It was like Theodor Kaluza, who added a fifth dimension in order to explain gravity. Because of string theory, the value of dimensions had been increased to 13.