Well, as I stated when I started this thread, there is an answer, but I can't tell you what it is, because you wouldn't believe me.
But if you do realize the answer, it will make you laugh--laughter always points to "your truth". Throughout your journey, your truths may change. As the world changes around you, so will your vision of truth. You will have to dig deeper and deeper to find it at times. But when you do, you will always laugh.
It is said that when the student is ready, the teacher will appear--this definitely applies to the question "Who invented time travel?" It is not up to me to decide who you choose as student or teacher. I would suggest, however, not to overlook the most important teacher of all--yourself.