“This is a ring of four laser beams. They create a massive gravitational field, with a strength at the center sufficient to warp space-time. Therefore, if a particle is placed in the middle of the ring, it will be pulled by the gravitational field. If you approach the field, both clocks and biological clocks will slow down. If someone steps into this ‘time tunnel,’ they might appear at some point in the past.” Professor Carter became excited.

“What exactly are you trying to do? Travel to the past and change history? If that’s the case, wouldn’t everything we have today just vanish into thin air?” Matthew Bolton shook his head. He simply didn’t believe time travel was possible. Time travelers in novels might be overused, but this is reality, not some fictional story! Time travel? Dream on, you bunch of scientific madmen! He sneered inwardly.

“You’re talking about the so-called ‘time paradox.’” Professor Carter smiled indifferently. “The American scientist Mac proposed that even if all the technical difficulties are overcome, the creation of a time machine would open a Pandora’s box full of logical paradoxes. If we assume there is only a single universe, as time moves forward, any attempt to enter the past or travel to the future would result in logical chaos.”

“The first paradox is that if a time traveler goes into the past and kills himself as a baby, then he would both exist and not exist, because he wouldn’t be able to grow up and come back to commit the murder. The second paradox is even subtler: the time traveler runs ahead of time and carves his name on a tree, but after returning to the present, he cuts down the tree, causing it to disappear from the future. Once again, we encounter a contradiction—at some point in the future, the tree both exists and does not exist.” Professor Carter fell into deep thought.

“These paradoxes put the theory of time travel in a predicament. If that’s the case, even if someone returns to the past, they probably can’t do whatever they want. But after finally gaining the freedom to travel through time, to lose the freedom to act and just watch history slip by without being able to change anything—wouldn’t that be a huge loss?” As Professor Carter spoke, his voice grew more impassioned.

“Then what’s the point of researching time travel? It’s a total waste of the country’s resources and taxpayers’ money!” Matthew Bolton muttered under his breath.

“Well said!” Professor Carter suddenly clapped his hands, startling Matthew Bolton.

“After countless deductions, we discovered that some laws of quantum physics can resolve these contradictions—in the subatomic world, quantum uncertainty dominates: when an electron collides with a proton, it might turn left or right, with no pattern to follow. In our view, this uncertainty creates the ‘multiplicity’ of the universe. Every time an electron turns right, it forms a new universe with the electron that turned left.” Professor Carter explained the profound “scientific theory” in one breath.

“I don’t get it.” Matthew Bolton shook his head.

“In other words, there isn’t just one world, but many parallel worlds. When you go back to the past, it’s not your own world, but a world similar to your history. If you interfere with history, the future will head toward a world different from the one you came from. You can act freely, without being constrained by the original history.” Professor Carter let out a hearty and proud laugh. “Now do you understand?”

“Crazy, absolutely crazy.” Matthew Bolton shrugged. “May I ask, Professor Carter, why did you have our director bring me here? You’re not planning to make me your test subject, are you? I absolutely refuse.”

“No, the test subject is an animal, not a human. Don’t worry. I invited you because I value your inner painting skills. This time machine only has one step left: to engrave the final space-time coordinate symbols on the inner wall and weld several laser pulse signals together… To complete such precise work by reaching the inner wall from outside the machine, only your exquisite inner painting technique will do.” Professor Carter picked up a slender diamond engraving knife from the workbench nearby.

“Oh, I see. You gave me a scare. All right, I’ll give it a try.” Matthew Bolton took the engraving knife and was about to approach the large sphere.

“Wait!” Professor Carter pressed another button on the remote control in his hand.

Two soldiers, also dressed in white lab coats, carried in a wolf that had been anesthetized and was unconscious. A small silver button had been sewn onto the wolf’s ear.

“Ah, it’s that wolf!” Matthew Bolton immediately recognized it as the wolf that had been following them.

“Heh, we originally planned to use a white mouse, but it turned out this wolf was very strange, lingering around here all the time, so we decided to use it as the test subject. Look, on its ear is the laser solar-powered far-infrared detector we invented. As long as it’s still on Earth, we can track it.” Professor Carter made a gesture, and the two soldiers placed the wolf inside the large sphere through the entrance.

“Please, our young and outstanding master of inner painting arts, you are about to complete a work for the ages and personally witness a great scientific achievement!” Professor Carter patted Matthew Bolton on the shoulder.