Black Hole

Stephen Hawking explained blackhole and blackbody radiation from blackhole. It was established that blakhole re-radiates like a blackbody from the residual energy after the supernova and cools down further. The frontal re-radiation is the future light cone, the event horizon is the world line and the backside re-radiation is the past light cone. That's how past, present and future are related in a blackhole. Therefore time travel is possible through blackhole.