I wrote the following back in December of 2008 as I was getting ready to fly home from a training trip in Australia. I was thinking about this today, so thought I would find it and share it along with the addition of a couple pictures.

——————————————————————————————————————————————

Time travel has been used as a plot device in literature since the late 1700’s. Charles Dickens used a form of time travel in 1843 in A Christmas Carol. Many of us will be watching this story on TV or video this month.

Time travel in literature was made popular in the late 1800’s with H.G. Wells – The Time Machine and Twain’s – A Connecticut Yankee in King Arthur’s Court.

In the 1900’s as Science Fiction gained respectability as it’s own genre, time travel was used more frequently. We have seen many TV series and movies that also used time travel as a major part of the plot.

• Star Trek
• Star Gate
• Back to the Future
• Terminator
• Bill and Ted’s Excellent Adventure
• Superman
• The Twilight Zone
• Disney’s recent movie – Minutemen

So, is time travel possible? One of my students asked me if I had the ability to time travel, would I go back to the past or on to the future. Scientist argue that one-way time travel to the future may be possible based on the theory of time dilation, but that travel to the past is not possible. I argued to my students that if time travel to the past was possible sometime in the future, we would know about it today because someone would have come back from the future to tell us about it. ? Maybe UFO’s ? :-). Anyway, I personally do not believe that time travel will ever be possible. But…

Would you call what I am doing today time travel? In a certain sense it is. It is a little past 10:00 am on Saturday here in Sydney. I will be landing at the San Francisco airport at 10:43 am on Saturday morning. I am still at my hotel in Sydney, how will I make it to SFO only a half-hour from now? I actually leave Sydney at 4:15 pm and by the Calendar and Clock actually arrive before I leave. Of course, I have done this many times before, and in Sydney the time continues to advance as usual as my clock turns backwards.

So this brings up another question. Einstein theorized that a person who is moving at a high speed would age slower than one that remained at rest. You have all probably heard of the example of the astronaut who rockets off leaving a young wife, only to return in a couple years to see his wife become an old woman. This is based on the theory of velocity time dilation. So, does all the flying that I do keep me young? Well actually there is also another theory called gravitational time dilation. In this theory the closer you are to the center of the earth, the slower time moves. So when I am flying, time is actually moving faster. So which of these is a greater factor? Studies have been made that show the effect of gravitational time dilation is stronger than that of velocity time dilation. So, I am aging quicker when I fly. This must not be why I retain my baby face.

Steven