Well, this is a travel blog so why not speak to the ultimate of all travel? This is something everyone has wished at some time in their lives. The thing is, we all are time travelers in a sense, since we are traveling through time every day. But, when we think of time travel, there is typically only one direction in time we seek: backward.
I remember my older daughter loving the movie Napoleon Dynamite. I watched it with her several times. There was the uncle in the movie I remember the most as he was obsessed with going back in time to reclaim his glory high school years of football.
Many of us would love to go back and "fix things". With the benefit of hindsight and aged wisdom we see the mistakes that we would love to rectify. Or maybe we just want reclaimed youth. The reasons vary, but the direction we want to travel is the same: back in time.
Mathematically it's perfectly allowed! Any math equation will tell you it is a simple thing to go back in time. It is so easy to do on paper, as all you need to do is put a negative sign before the "t" , which symbolizes time in any math problem.
So why can't we do it in real life? I was actually quite obsessed with obtaining knowledge of time a few years back. Not time travel, but the nature of time itself. Enough so that I focused my quantum physics reading on understanding the nature of time. I mean, what exactly is it?
Most give time little thought. We understand it as a marker of events. It puts life in order. It answers the question "when". Our understanding of time is simple enough, it is the chronological dictator of our lives.
But to me there has to be something more to it. There has to be an origin to it, right? Whether you are religious or not, it should strike anyone as peculiar that the first verse in Genesis, which means the origin of things, starts with, "In the beginning God created the heavens ......".
The beginning of what? Time! What was created that first day? The heavens, or space. So, in its basic meaning, the verse claims time and space were created together.
That knowledge was given to man long before Einstein coined the phrase "space-time". He proved that space and time are inseparable, one cannot exist without the other. Time is a separate dimension just as the three dimensions of travel (up, down, and sideways as the x, y , and z axes represent in mathematics) are in our universal realm. A separate dimension, but part of the same realm as up and down are in space-time.
But that speaks to the origin of time, not the answer to the direction of it. Why can't we travel back in time? The consensus of scientific opinion seems to center around the concept of entropy. Entropy is a measure of the disorder of things. And the direction of entropy is set. Entropy is increasing in the universe, meaning things are getting more disorderly.
I don't mean to get so technical here that you stop reading, but it means you can no more go back in time than you can put an egg back together after it has broken on the floor. The laws of physics are set, and it is simply not allowed, as far as we know. The laws of physics point in one direction: things fall apart over time, the two seem interrelated. We fall apart over time, so does our house, trees, anything of structure. Time and entropy seem intertwined.
But, although I've read that explanation by many prominent physicists, it never truly answered the question for me. I've been obsessed with this interwoven nature of time and space or "space-time". It just seems the nature of time and it's direction is found there.
Every event in our lives is defined by "space-time" isn't it? When you describe or recall an event it is within that realm. The event happened at a certain location (space) and at a certain time. You can't fully describe the event of your birth accurately by saying where you were born, but more fully, where and when the event occurred. The two are inseparable. Both time and space are required to fully describe any event.
I came across a book written by Richard Muller, a prominent physicist, writer, and professor at Berkeley college. His take on the direction of time is different and seemed closer to the answer to me. I really dislike paraphrasing his book, as I'll likely get it wrong, but my understanding of the essence and direction of time from his is book is that time goes in one direction because time, like space, is still constantly being created.
We know that space is being "created", if that's the right word. Scientists can measure distant galaxies and know they're getting further apart, the universe is expanding! Galaxies are moving away from each other faster than the speed of light! Now nothing moves faster than light, right? Well that's true, nothing is faster than light moving through space, but what if "new space" is being created? Then no laws of physics are violated and galaxies can expand faster than light.
I expect of the five or ten of you that read this, I'm down to maybe one by now. But this is just too interesting to me not to write about in this blog somewhere. What Richard Muller proposes (as I recall, it's been a few years since I read his book), is that since new space is constantly created in the universe, so is time created, since they are intertwined. We are simply living in newly created time (and space, I suppose). We can't go back in time because it's spent, doesn't exist anymore.
That's a fascinating take on time to me. But, from what I've read, space (and time) are only expanding (being created) in the distant universe, between galaxies. Within a galaxy, like our Milky Way, gravity keeps things together and space is not increasing.
I emailed Dr. Muller with my assessment without expectation of a reply. But within a day he answered my question. I was shocked such a prominent man would educate my ignorance!
He explained that space-time is expanding locally. Here was his response to me:
In my theory, space-time is expanding locally. It doesn’t affect the size of an atom because that is set by quantum physics. It’s like you sitting on the top of an expanding rug of rubber; you don’t change size, but people close to you move away.
Thank you for the careful reading and consideration of my arguments.
Wow! He actually thanked me for my "careful reading and consideration". That made my day, week, month, and year! Maybe he mistook me for a fellow physicist and not the inferior Chemical Engineering education of my background.
I suppose the distance between everything could be expanding locally despite gravity (thus time is created locally), but we would never know it. The average distance to the moon might always be 238,900 miles if the yardstick we use to measure it is also expanding proportionally to the local space it occupies.
It's fascinating to me that in a black hole time stands still (I'm assuming black holes exist as there is only indirect evidence of them). Time is all but nonexistent inside a black hole. They have so much gravity that everything is "pulled in", but cannot escape (I won't get into Hawking's radiation). Since it's so dense inside a black hole, it's as though even space does not exist. So if space is all but non-existent it stands to reason the same for time. That seems to be at least anecdotal evidence for Richard Muller's theory.
Anyway, I have never read a better assessment about the matter of time than Dr. Muller's. I have no idea if he's right or not, but it's the most reasonable explanation I've come across. We can't go back in time because "old time" doesn't exist, at least in our realm. We are living in newly created time and space! What a mind blower for me!
Anways, thank you for joining me in my journey through time and space. Just think, the five minutes or so you wasted reading my ramblings, you'll never get back. It's spent! I bet you wish now you could go back in time now!