Time is a big definition of the universe, which refers to the flow of objects in space. Time reversal is impossible for human science and technology now. Time reversal itself is a natural phenomenon, and the time axis is a model used by human beings to study time. Like light, it does not exist. Our universe is in the timeline direction of our universe, but the timeline direction of other universes may be different from ours. There will be turbulence of time at the boundary between our universe and other universes, and time and space will be distorted. Humans call it a black hole, not a black hole of star debris. This place may be reversed in time, but it may be the most dangerous place in the universe. Any object will become submicron, but it is not caused by force, but by spatial change, and it will fly to all time points like sand blown by the wind. Matter is still in space, but space is falling apart. If we put people here, they will collapse, but there will be no blood flow. More and more broken, more and more invisible, no one knows whether he is dead or alive, and there is no way to understand what it feels like, except that it is a very tragic ending. Of course, humans can't reach such a place.