Time and Multiverse

There are two attributes to time :regularity and direction.

Regularity - Every second is equal to the second before it and the second after it. This is true no matter where you are in the universe and has been true in the past.

This is NOT true if traveling faster than something else. The seconds are longer when traveling faster. All the processes go slower. This is one of the effects that are predicted by Einstein's theory of relativity. There is the example of two twins, one who speeds through space and the other remains on earth.

When the astronaut returns to the earth he finds that he is younger than his twin. Depending upon his speed there would be a difference of years.

In the chapter on the philosopy of science I stated that in order to check an explanation or assumption it is necessary to find an experiment that will test the predictions. Only after a number of such experiments where the results match the predictions is the explanation called a "theory" or even a "law". This difference in the length of time was checked by two atomic clolcks that are the most exact. One was put on a plane from New York to Los Angeles, and the other remained in the NY airport.

When the traveling clock returned it was slower than the other by a fraction of a second - exactly as the computations had predicted.

Direction - We progress in time from the past to the future. Amazingly enough many equations of physics allow the possibility of the progress in the reverse direction. There are even equations where time is negative. This is simply ignored.

We know how to travel to the future, simply by traveling fast. When returning we see that the earth time is much more in the future than we are.

Can we travel to the past ? YES. However if we do so we move to an alternate universe. There was a paradox about a man who travels to the past and kills his grandfather. How then, is he born ? What happens to him ? The answer is as I said before that he also traveled to an alternate universe that is similar to ours and finds a man who is similar to his grandfather. If he kills this man he will NOT be born in THAT universe. There is no problem about his own existence. (He will not be able to return to our universe.)

The multiverse

Many people think that our universe is the only one. Actually there is an infinite number of universes. Some of them are identical to our own. There are a number of possibilites for the outcome of any situation. Each outcome produces a different universe. In each universe the participants feel that their universe is the "real" one.

It is known that "empty" space is not empty, but seething with activity wth particles that suddenly pop into existence and also suddenly disappear. They come from and go to different universes.

There is also the problem of what happens to the stars that fall into a black hole. To where does the energy and information disappear ? According to the conservation of energy and information this can't happen. They also go to a different universe through the center of the black hole which opens up to a white hole. Sometimes a very large black hole will explode and in the process creates another universe. This is one of the possibilities of how our universe was created. The big bang was an explosion of a black hole in a different universe !

The beginning of wisdom is the understanding of the vastness of our ignorance. Attached to our feeling, on any subject, of what we know there is a lot more that we don't know, and we are discovering more new things all the time. Note what people thought was true 100 years ago. Today we know that most of it was wrong. This is the situation of what we know today, that we will find out in the future where we were mistaken.