Questions about Time, Distance, and Relativity

[Surgenator]

Only the photon experience no passage of time. From the photons perspective, it has traveled 0 distance at 0 velocity for 0 time. To any other non-speed-of-light observer, the photon travels a non-zero distance at velocity c for a non-zero time. This sounds very wierd because traveling at the maximum speed limit of the universe is like doing math with infinities (and techically you are). It can be done, but it's really hard to have any intuitive sense about what is going on.

I still have problems conceptualizing relativity's predictions. However, you can't argue with results.

Yeah, it's quite confusing... Greene writes, "Einstein proclaimed that all objects in the universe are always traveling through spacetime at one fixed speed--that of light... If an object does move through space, however, this means that some of the previous motion through time must be diverted... We now see that time slows down when an object moves relative to us because this diverts some its motion through time into motion through space. The speed of an object through space is thus merely a reflection of how much its motion through time is diverted... the maximum speed through space occurs if all of an object's motion through time is diverted to motion through space. This occurs when all of its previous light-speed motion through time is diverted to light-speed motion through space."

Can you elucidate that?

This is the first time I heard about we all moving at the speed of light. It does seem strange, and I would need more time to think about it. I did found a good link that discusses this specific topic. From my quick read of it, that we transverse the 4 dimensions at the speed of light. However, the amount we spend in the time dimension is what determines how much time we experience. Light, for example, doesn't spend any amount in the time dimension and hense transverse the space dimensions at the maximum speed.

Not necessarily. You can still have events that no matter what reference frame you look at, the order of the two events would not change.
No.

How so? I'm still a bit confused here, particularly on the last point... I'm sure this is a very amateurish question, but if time is not absolute as once conceived, how can an absolute age of the Universe be given? Because the speed of light is absolute? But wouldn't that be... zero? As a hypothetical aside, could spacetime ever be warped to such a degree that it "turns in on itself" and inverts causality?

This is not an easy nor amateurish question. My head is running in circles trying to come up with good answer. I know it has to do with time-like intervals and setting it up the events correctly.

Here is one possible explanation, but [b]I don't know if it's right.[\b] At the big bang, all of space was concentrated to a single point. Now, we can observe 13.8 billion years has past since then. So how far did we move in 3D space relative the big bang, 0. Yes zero because all the space was concectrated to a single point and expanded to what it is now. At any location you're standing now is all mapped back to a single point (this is what they mean by the big bang happened everywhere). So when you do the spacetime interval, you will always get 13.8 billion years has passed. This is independent of how fast your moving since every space lcoation is mapped back to a single point.

Maybe Alex has better luck. He sounds confident.