Yesterday night, when my daughter asked me the most confusing question, time travel came into my mind. She told me that she really wanted to know what the outside of the universe was like. It reminded of the same question I asked my father when I was a kid. I didn't know how to answer my daughter just like my father many years ago. Then I got out of her room and stood by the window. When I looked up to the night sky, I had a strong will of having a time traveling machine to travel back to the very beginning of the existence of the universe so I could know its true origin. Then I noticed a plant in the living room, its green leaves looked really charming under the light. I have heard a saying from Buddhist texts which tells us a leaf is an entire world. Many ancient people couldn't understand what that saying means until we found a tiny world thanks to the microscope. So, what is the tiniest element in the world? Quark? Maybe not! Actually, we only know little about the world. So, time travel can't figure out my problem either.