There is evidence that black holes could be used for space and time travel. Black holes are areas in space where space-time is warped due to gravity being quite dense. They form when a star dies and explodes. As of right now, black holes can not be used as wormholes but could be used as a gravitational slingshot to help propel a spacecraft through space faster. Black holes can be used as time machines thanks to them being super dense. Hopefully, black holes will be a means of space-time travel in the future when our technology becomes better.