According to some members on this site and other facts I've found, it would be possible to travel towards Earth with such a velocity that Earth would perceive the traveller as a black hole. Inversely at that same speed, the travelleler would see Earth as the black hole. What would happen when the traveller entered the black hole. My guess, is that space has a limit to how much mass it can contain. The size of the black hole compared to Earth, will be just large enough to contain all the relative mass of Earth without breaking that limit. In other words, its center of gravity will be larger than Earth itself. I believe what would happen is that the traveller would think hes going straight in, and would end up on the other side of the black hole. This seems to violate less things, because if he could crash into the planet, well, idunno.