Question

What is exactly Black hole and how can we travel through time ?​

Answer 1

The reason that this is possible is that the relevant singularity inside a rotating black hole is technically “weak,” and thus does not damage objects that interact with it. At first, this fact may seem counter intuitive. But one can think of it as analogous to the common experience of quickly passing one’s finger through a candle’s near 2,000-degree flame, without getting burned.