That was a great documentary by Stephen Hawking- "Into The Universe" shown on The Discovery Channel.
The size of the cosmos boggles the mind.
Interesting was the refutation of "going back in time" due to the paradox caused...but the possibility of "going forward in time is possible.
I still cannot understand why nothing can go faster than the speed of light (186 mps)...I have to further investigate this.
And yes, time is different in different places is an interesting situation as you highlighted Trigs. Practically, this is why certain GPS Systems malfuction every now and then...because they have to be adjusted for the time differential. I once was sent to an incorrect location with my GPS...the correct address was about 2 blocks away.
The possibility of Alien life out there is a given imo, based on the scope of the cosmic real estate.
This should be "must see" for science buffs.
As we bring up time and causality, I thought I would mention an interesting study...
A physicist working on models of the universe's expansion found that causality may not be simply a human concept after all. Models which did not have causality either ended up completely flat or like crumpled pieces of paper, neither of which would allow our universe to develop as it has. However, when causality is added, the model turns out perfectly, suggesting that causality is an inherent property of space. This is just a model of course, but it is pretty stunning since, in physics as well as philosophy, it had been believed that time as a one-way street is a human concept.
and speaking about time (i watched an interesting show on it last night), it just boggles my mind to even consider the notion that time runs faster or slower depending on where you are or how fast you're going. i honestly have so many issues trying to understand this idea.
more specifically, where ever there is a stronger gravity, time travels slower. so, for example, if we could fly around near a black hole, we'd could theoretically travel into the future (so to speak). or if we could get up to a speed close to the speed of light, it would work the same way.
the simply fact that our gps satellites, which are not really that far away from us, must be programmed to run their clocks slighty off of 'regular' time i find just freaky to think about. it's a tiny fraction of a second difference (something to the billionth i think), but still could cause huge problems if not adjusted for (don't quote me on it, but i think it works out to 6 metres a week difference in positioning).
the fact that time is relational seems quite influential on the notions of cause and effect. afterall, cause and effect work within the notions of time necessarily so.