After reading The Universe in a Nutshell by Stephen Hawking a while back, I discovered that he may have made a mistake — and probably Albert Einstein, too!
It has to do with the concept of time slowing down or speeding up.
One reason that the idea of time slowing down or speeding up makes no sense to me is that Hawking never defines the word “time.”
He actually admits that he had a hard time understanding what time is. Einstein couldn’t define it either!
Once you force yourself to define what you mean by the word “time,” or any word for that matter, misconceptions get cleared up.
Words, after all, are only symbols that stand for something. Some words have very specific meanings, but many are vague or abstract or generalizations.
When there is confusion, the question to ask, then, is always: “What do you mean by that word?”
What is time? My answer is that it is simply a measurement of speed. It is a comparison between the speed of change of one thing, with the speed of change of another. It is like inches or feet.
Time is the same thing, except it measures duration, not length, in its comparison.
The most obvious use of the word is comparing changes on the earth and in our solar system. A year is the earth circling around the sun once. A day is the full rotation of the earth on its own axis.
When I say it takes me two hours to drive to LAX, that means that while I am driving to LAX the earth rotates a twelfth of a day.
This kind of measurement uses one full rotation, or a day, as the comparison. We can divide that downward into hours, minutes, seconds, etc. Or we can add it upward into weeks, months, years, etc.
To be 65 years old means that the earth has circled the sun 65 times since you were born. The comparisons we use to measure longer times extend from years to centuries to millennia.
When you get into bigger comparisons, you use light years. I suppose we could go even bigger: How many “big bangs” does it take to …?
In his book, Hawking gave a theoretical “mind” experiment involving twins. One stays on earth and the other flies off in a rocket ship at the speed of light for a while.
When he returns, he is 2 years older than the other, or younger, or something like that …
No, Steven, I am sorry. First, nothing can travel as fast as the speed of light except light — according to both scientists.
Second, getting back to “time,” our earth circled our sun the same number of times during the experiment, no matter what happened to each twin! I am sorry — if you use that basis for measurement, you have to stick to it!
As you may have picked up on, I am not a physicist, and I probably misunderstood the point. However, both Einstein and Hawking said they couldn’t define time.
I suspect that what they were talking about may have boiled down to the deeper question of existence itself: “How is it possible that I exist now, but I won’t in the future? Here I am traversing the world, but one day I won’t be. Why do we exist for the time being (nice phrase), but then we don’t?”
Those are very good questions! The great question in my opinion, though, is not one of the measurement of the duration of being — i.e., time. It is the mystery of being itself.
Too bad I hadn’t published this when Hawking was still around. We could have sat over a cup of coffee when he visited UC Santa Barbara and chatted.
Well, at least I finally had the time to publish my thoughts.
It’s about time!