Thanks. I am trying to wrap by brain around this in practical terms, from the point of view of two separate observers.
So let's say this thing we call 'TIME' only comes into existence at the point of creation.
We both agree that we are viewing the same event. You say that thing we call TIME, that only came into existence at the Big Bang, can be different for the two of us - RELATIVE TO US.
For me the event could have happened 15 billion years ago and for you only 13.75 billion years ago. I'm using smaller differences based on replies. But assume any difference, even slight.
If we are on different galaxies, let's say you are on earth, I'm in a different galaxy on a different planet.
What does 13.75 billion years even mean to me? I would have my own units of time based on my planets rotation, etc……If I never knew about earth I would have no idea of your concept of TIME.
I can only compare TIME relative to you based on your measurement of time. Right?
Maybe what I call 15 billion years on my planet could be exactly 13.75 years on your planet. Or maybe what I call 1 billion years is only a million years to you. I can only compare TIME relative to someone else.
So now the concept of 'TIME' becomes something based on you. Time is not 'external'. Time is what you experience and can only be different when compared to someone else. That's logical right?
Let me give you a better example. Say I build a time machine and I travel forward in time by a 100 years, but during the trip I lose my memory. How will I know that I have traveled forward in time? I won't know it unless I have some point to compare it to. I will simply be in the present, not in the future.
Now let's go back to the Big bang. We are on different planets. We both observe the same event - The Big Bang.
If we never ever meet each other to compare experiences. Time for each of us will be whatever we say it is. I can say the universe is 15 billion years old based on what I call a year. And you on earth can say the universe is 13.75 billion earth years old based on earth time.
If we do meet, or contact each other somehow, and want to compare our notes on the age of the universe. One of us will have to convert their units of TIME to achieve anything.
If we do this. I can only conclude that my 15 billion years is exactly equal to your 13.75 billion years. Because TIME is only what each one of us says it is.
You could of course use my measurements and agree that the universe is in fact 15 billion Spagoolars old (that’s what we call a year on my planet).
In either case we are using the same measure of TIME. A UNIVERSAL notion of time. If TIME indeed has a creation point at the moment of the Big Bang.
Lol. I am getting lost in all of this. But thanks for taking the time to engage. I love this topic.
I can't help but feel there is something very important here.
If you get into a spaceship and travel at twice the speed of time. Or close to a black hole as per your example. How will you know that you are experiencing TIME different to me? You can only know if you compare it to me and convert your units of time to mine.
If you come back to earth from your trip to the event horizon and find that I have aged 60 years and you have only aged by 6 years. Then your 60 years must be equal to my 6 years. Right? If its equal it must be the same. Right?
This only matters if we have a "start point" or "big bang", lets say you left for the event horizon when we were both 20 years old. That's our reference point. If you have no reference point, you could go to the edge of a black hole and come back and never know that you traveled faster or slower because you have nothing to compare it to.