Difficult one to answer it.Christopher Nolan presented a theory of time travel in his movie Interstellar. Now there he took massive black hole so that it was not so much dangerous as it's eating rate of material is slow than stellar one. When I researched about that I find it's possible to do travel in time by a wormhole.when I wrote bout it, I took help of AI. there I saw if time rate of flow is different in different spaces(I imagine they are far away so) then synchronizing frequency we can get time travel. Now travel through space? Nolan showed us inside black hole through singularity we may go to another space of this universe. Now scientifically it is true? Possibly a wormhole connects two distant region of space as shown in figure below. While doing chat with AI, it shows me that to create such a wormhole we need black hole. More theoretically I don't talk here. Here the role of dark energy is not known to me. I know exotic or negative matter play a role in creating such a wormhole.