Where is the border between science and fiction?
Science fiction is the generally accepted English name for a story concocted science occurs.
Often fantasies were or are invented later to belong to the real possibilities.
Famous are the stories of Jules Verne. Consider the 'trip to the moon'.
The laser beam was invented and constructed after previously imagined.
"Parallel Universes" is a concept that certainly came from an angle of science fiction but today
it is a serious cosmological understanding.
Therefore the boundary between science and fiction can be exceeded.
A science fiction writer is a great author when the reader asks: can that be real or am I tricked?