Originally Posted by
M16
The white hole bit is just a theory with no real evidence. While a black hole is an object that is so dense that not even light can escape it, a white hole is "the opposite." Scientists are not exactly sure why, but "white holes" seem to be objects that constantly spew out matter at an incredible rate.
While there's no certainty as to exactly what they are, scientists postulate that some of the matter that gets "sucked" into black holes will be ejected through to some other point in space and time. There are certainly no theories on white holes opening up to parallel universes, as that's not exactly a scientific idea. More of a science fantasy, which isn't really very scientific.
The problem I've got with the idea that extraterrestrial beings can travel through worm holes (connected black holes) is that it's just a physical impossibility. First off, they're impossible to actually see, so it'd be pretty darn difficult to find them. We can detect them, but can't see them. Second, by the time any matter comes into "contact" with a black hole, it just gets crushed down and pulled apart so instantaneously that it pretty much ceases to exist.
I'm not exactly thinking outside the box, but I just don't think we'll ever come into contact with any sentient beings from another solar system, another galaxy, or another parallel universe. It's just too physically impossible.