As a disclaimer to this post I would just like to note that I have no background in physics, but have read books by Hawkins and Greene, and as they say, a little knowledge is a dangerous thing. Also, I have questions about how science has calculated time and distance, but I am not trying to make any point whatsoever in regards to my Christian faith. (I don’t find my faith and science in conflict at all.) I am just trying to understand better what it is I’m reading.
I find time as defined by relativity fascinating and confusing.
For example we say that a particular star is 10 billion light years away. We are saying that the light from this star took 10 billion years to reach us travelling at the speed of light. If however we had a seat on the photon travelling here no time would have passed at all. If you have zero time, then no matter what the velocity is, you have zero distance. In other words from our perspective the universe is huge, but from the perspective of a photon we are back to a singularity with the Earth and the star being co-located. As I see it, as photons are always travelling at the speed of light, it is still existing at the exact same instant as when it came into being. Which view represents reality?
Also, in Greene’s book, The Fabric of the Cosmos, he says that if someone on that star 10 billion light years away started walking towards me at 10 mph it would put him 150 years in the future from my perspective. I understand that the speed of light is constant relative to everything regardless of motion. However motion causes time to change, (as I understand Greene). As everything is growing further away from everything else then everything is in motion relative to everything else. As there is no standard reference point in space there isn’t a reference point for time either. We can’t say how fast we are moving through space, as there is nothing to reference our rate of motion to. Doesn’t this mean that the relative time between us and any other body is something of an unknown? If in the end, as time is relative, does a year have any real meaning; and if it doesn’t then neither does the term light year.
It just seems to me with my extremely limited understanding; relativity makes it impossible to say that the universe is a particular size or age because we can only measure things from our perspective on space and time. If we were elsewhere in the universe with a different vector in time and space wouldn’t we come to entirely different conclusions? How can we say what perspective if any represents reality? Please keep any answers simple as the only math I’m prepared for is distance = velocity X time.
This message has been edited by GDR, 07-28-2005 09:26 PM
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