Nonfictional Theory
A more accurate, or appropriate term, would be alternate universe, or parallel worlds. Theoretical physics discusses several theories of dimensions.
Ufology discusses scientific theories of dimensions, beings, and intelligence, and may consider the paranormal. Scientists attempting to ascertain the nature of UFOs and Unidentified Aerial Phenomena (UAP) consider known physics and theoretical physics; and when no prosaic explanation can be found, discussions of another dimension, of "manifestations of nature from perhaps another dimension".
Because modern science on Earth does not have a real concept of multiple dimensions beyond quantum mechanics and the many worlds interpretation, bending or changing space-time itself to achieve faster-than-light travel appears to be the real-world equivalent of jumping through dimensional doorways in fiction.
"Beam me up Scottie!"
In the Star Trek universe, wormhole theory states that if a section in the fabric of space-time joins together with another section of space-time, a direct connection can be made between the two, allowing speedy travel between the two (normally unrelated) space-time coordinates. Black holes are one such way of stretching the fabric of space-time; so it's theoretically possible to create wormholes using a pair of singularities, at least in the fictional universe of Star Trek.
The NASA Website has a somewhat dated article called "The Science of Star Trek", by physicist David Allen Batchelor (5 May 2009), which considers some of the implementations in Star Trek. He says it's "the only science fiction series crafted with such respect for real science and intelligent writing", with some "imaginary science" mixed in; and considers it to be the "only science fiction series that many scientists watch regularly", like himself. He says it's "more faithful to science than any other science fiction series ever shown on television". STAR TREK FOREVER!
Were Inter-Dimensional Beings Considered Gods?
I have always been a huge fan of the writer Graham Hancock and his theories of lost ancient civilizations and their writings reflect connections of higher intelligence in the Universe. He talks about this in his thought provoking documentary: (abbreviated version)
http://www.youtube.com/watch?v=L0XRDBoWbrA
Hancock says that are different levels of reality and dimensions. He believes that UFO's are not coming from across the galaxies and Universe by interstellar travel to visiting our planet but from other planes of existence or crossing dimensions. There have been records dating thousands of years old in many ancient cultures including: Babylonian, Sumerian, and the ancient Egyptians mentioning about the knowledge they received from the gods or "Guardians of the Sky" (non-human entities) and now scientists are taking a fresh approach with that information and taking it seriously.
Next week's blog: I'd like to talk about how inter-dimensional beings can possible play a part in a haunting. It seems these E.T.s and paranormal activity can have a connection!