Not only do you have to contend with the fact that spacetime is four dimensional (3 space directions plus 1 time direction), but the time direction is very different, so it’s four dimensional in a really weird way.
Now add to that that black holes royally mess things up and you’ll find yourself in dire need of a better coordinate system to make things easier to picture. Although the situation is still a little weird, time points more or less up (the standard set up for space/time diagrams), and light travels diagonally (again: standard).
A black hole is a funnel that pinches off at a singularity.
Now the point: you can write down a lot of the physics of general relativity in these coordinates and they look pretty good, so it like there’s something to them. General relativity treats the stuff on the left the same way it treats everything on the right (our universe).
So, given the history, physicists today are a little hesitant about chucking out solutions, even when they’re silly.
And black holes are a bottomless pit of math with solutions that seem impossible.
Physicist: The short answer is: A worm hole is a “tube made of spacetime” that connects two different regions.
If it’s set up right, you could enter one side of the tube and exit the other end somewhere else, or even else.For example, they assume that the black hole exists forever (into the past and future) at the same size.