the desire to keep writing

With each word a new scene happens in our world, and even though it is fiction the possibilities are there that weren't there before.
Why is it so difficult for me to think of alternate dimensions to our own? We couldn't think microscopically until the microscope was invented. Will physics be able to reveal, within human perception, other realms? When computers gain sentience on a human scale, which I have no doubt will eventually arrive, it could be our first venture into alternative dimensions.