Ideas of time travel have existed for centuries, but when Albert Einstein released his theory of special relativity, he laid the foundation for the theoretical possibility of time travel. Now, we may wonder, if time travel were possible, why haven't we met a time traveler from the future? Physicists such as Michio Kaku who wrote a book on Parallel Worlds believe that the universe is full of parallel universes. We are but a tiny atom within the whole cosmic reality. As such, we see the universe from our tiny perspective.
Imagine, like Alice in Wonderland, we could eat something that would make us grow bigger. Now imagine that there was no limit to how big we could become. Think of a tiny ant who became bigger and bigger. This ant would be amazed at what he saw. The world appeared alien the farther away his perspective became. So, let's imagine that we grew larger than the planet (let's assume air is not an issue). We became obsessive and decided to see how large we could become. If our hypothetical ant was amazed at the sight of civilization, he would be totally confused at the sight of the planet earth. The larger we made ourselves the more amazed we would be. That is, until we became so large that we no longer recognized the cosmos. Once we became larger than the viewable universe in which we live, we would see exactly where good 'ol planet Earth fits into the whole scheme of things. I assume we would, like the ant, become downright confused at what we saw. We can imagine that this huge person saw multiple universes existing within some some astronomic something. Maybe this person saw the universe explode, implode over and over. Would he see what runs it all? Would he see the beginning of something? Becoming larger and larger would he see the face of God? Maybe he already did and didn't know it. Is God a deity, an energy or force or maybe all of the above. Does God exist? It all depends on your definition of God. Does it matter? To each individual it does.
Out of fear, this bombastic person would then eat the "get smaller" food, like Alice did. Again, this person being driven by anxiety may get carried away and shrink down to the size of an atom and beyond. And, once again, he would become confused, disoriented and possible afraid. He would see an alien world before him. He would see the energy which makes up our known universe. What would he see? Would he see the face of God?
It all comes down to perspective. Einstein understood that perspective was everything. So, basically, our world is our world and no one else's world. That is because we see it in a way no one else sees it. Does it matter? Yes, it does!