I remember my 6 year old telling me about wanting to go visit "Billy." I assumed it was a kid from school and was glad he'd made a friend. When I asked him what Billy looked like, he told me he had green and purple hair and orange eyes. I asked him where Billy lived and he answered "In Billy's house..." Imaginary friend or maybe something else?

There is so much to the universe that we don't remotely comprehend. Stephan Hawking (and many other scientists) believe there are multiple dimensions and that time is not linear. Just because we don't know how to prove that exactly yet doesn't mean it isn't true.