Monday, November 14, 2011
There was no football game on when I was working out the other day so I was forced to watch PBS. Fortunately it was one of their rare non-fund raiser days and they had a program on that wasn't about cheese making or men sitting around in a circle beating drums trying to find their inner children. It was Nova -- The Fabric of the Cosmos: The Illusion of Time.
I have to admit, I am a sucker for theories on time. So as I climbed/jogged to nowhere on the elliptical machine, I was engrossed in the program that attempted to explain in semi-layperson's language what time was (not what time it is, because does anyone really know what time it is).
The most fascinating thing about the program was that it debunked our standard perception of what time is. We always describe time as passing or as Steve Miller sang, "slipping, slipping, slipping into the future." But according to Einstein, time is more like space. It flows in all directions at once.
The other thing the program pointed out was that time and space co-exist in something known as the spacetime continuum. So where we are in space affects where we are in time. The program described the concept of "now" as being a single slice of the spacetime continuum. But no one's slice of spacetime is the same, so everyone's experience of now is different. Apparently an alien living in another galaxy experiences a "now" that is 200 years ago in my time.
And the speed at which we move also impacts time. When something isn't in motion (i.e. slumped in front of the television) time clicks away at a normal speed. Scientists confirmed this by taking two Atomic clocks synced to the exact same time, placing one on a jetliner and leaving the other one on the ground. The lucky clock was flown around the world on the jet. When it returned it was no longer synced to the clock that had stayed still. It was a few microseconds behind.
Physicists also believe that, in theory, going backward and forward in time is possible. To travel to the future, all you have to do is hop in a space ship and fly near a black hole and hang out for a few minutes. When you return to earth, 50 years will have passed and you will have only aged 5 minutes.
Travelling to the past is a bit more complicated. First you need to find a worm hole (an hole in a slice of the spacetime continuum that connects to another slice in the spacetime continuum). Then you jump into the hole kind of like Alice chasing the white rabbit and bam, you are in a slice of the past. Unfortunately you are at the mercy of the worm hole and don't have much control on where or when in the past you end up. My luck, I'd wind up back in the 70s again.
Physicists are skeptical about whether or not you could really travel to the past. They base this on the lack of visitors from the future milling about taking photos of your backyard and the dilemma of people travelling into the past and meeting themselves and advising against eating that marked down Sushi from the supermarket. I kind of pooh pooh these things as proof that time travelers don't exist. For one, if you are travelling around in time I don't think you'd broadcast it. I'm sure there are plenty of people in mental institutions that made this mistake. As for creating a paradox by meeting yourself and altering time, I think the many worlds theory of quantum physics could counter that one.
The Nova program indicated that scientists grapple with the question of how time flows when it is actually just one massive component of the spacetime continuum that makes up our universe. My guess would be that time doesn't flow, we do. Just living our lives makes us time travelers. We are passing through the slices of time, not riding in a river of it.
I would also conjecture that what people think are ghosts or spirits could simply be layers of the same slice of time overlapping giving us snippets of other times and time travelers. This wasn't discussed on the PBS program. It was just something I thought of in my own unscientific way without a mathematical formula to back it up.
Regardless, I think it is time to go.