by Sally Morem

Created on: August 21, 2009

Is time a dimension the way the three dimensions of space are? Are the past and the future places we could travel to if we had the technical means of getting there?

I don't believe so. I believe all we can retain of our past is our memories and recordings of events that once took place and have now vanished forever. Likewise, the future consists only of our mental models, our anticipation of events that may one day occur. We can rationally anticipate the arrival of tomorrow morning. But it does not exist now.

We live in the Eternal Now.

The Eternal Now is a tiny sliver, a standing wave, an event that occurs and vanishes, and is then replaced by new events in a linear fashion. We anticipate it, it's here, and then we remember it.

If this is true, there is no question of traveling backwards into the past because there is nothing left to travel back to. There's no there there. And the only time travel we can engage in is the one we've always engaged in: To the future one second at a time as each succeeding second obliterates its predecessor.

Einstein says that space and time are inextricably linked in our vast universe of space-time. Some physicists believe that if we enter a region of the universe in which the space-time continuum is strongly warped, perhaps near a black hole, we can then travel far into the future or even into the past in apparently little time.

Traveling near the speed of light definitely affects the flow of events, slowing them down, nearly stopping them, in comparison to the flow of events in normal space-time. However, this effect still forbids any information from traveling faster than the speed of light. Why is light speed so important?

The speed of light is nature's ultimate enforcer of limits. It prohibits any bit of information to travel faster than it does. As such, it delimits events. No event can be perceived outside of its "light cone." No event can affect anything outside of those limits.

If a star goes nova 2,000 light years away from Earth, no one will be able to perceive it, not even 1,999.999 years from now. We must wait until the 2,000th year for astronomers to pick up that light wave. Just so. No future grandfather as a young man could ever receive any information about his future grandson well before he is conceived. The grandfather paradox can never occur because no homicidal grandson could ever breach that light cone before its time.

Seen as a series of unreplicable,

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