I read a sci-fi book written by Christopher Paolini. It included a several pages long addendum explaining how the FTL worked. The explanation was based on physics and findings of physics that will be uncovered in the future. The power needed for FTL was generated using antimatter. Speculative fiction but I appreciate that the author had managed to write a technical description that looked convincing and logical. That it was invented speculation rather than reality is a minor issue.
Biblical scriptures do not tell about alien life on other planets, probably because that information is not relevant to our relationship with God or our daily life. It may be interpreted so that other planets in this part of the galaxy do not have intelligent life or that aliens are not going to affect our life during the near future.