Another thing that is throwing me off

[Menoman]

 

Ok so there, I'm trying to figure out how its possible for frame of reference B, to think that time is going slow for frame of reference A. But also, at the same time, Reference A can logically say time has slowed for reference B.

 

I can understand the first graph. B says "I'm stationary" So A moving past my 2 clocks (Which are synced) will take less time because his clock is moving slower. So in "B"s mind, it only took A 45 minutes to travel what "B" see's as an hour's distance. That makes sense to me.

 

But the bottom graph, with A stationary with the 2 B clocks moving past. "A" will see 1 hour pass between the B1 passing, and the B2 passing, but in "B"s reference, it will only be 45 minutes?

 

 

Ok basically, in the first graph. On "B"s clock, "A" passes "B1" at 12:00, and then passes "B2" at 1:00... But, on "A"s clock he passes "B1" at 12:00 and "B2" at 12:45 that is correct?

 

 

On graph 2, on "A"s clock, "B1" zooms by at 12:00, and "B2" will zoom by at 1:00.

But according to the "B" clocks, "B1" zooms by at 12:00, but "B2" will zoom by at 1:00 also...? Thats how it seems to me because of the syncronized B1 and B2 clocks. But the relativity thinking side of me thinks its 12:45, but logically through relativity I can't explain it.

 

 

Now I understand that the relativity of simultaneity(sp?) is how this is explained, but for the life of me I cannot grasp the logic behind this, I've wrestled with it for a few days now.

[swansont]

There is also length contraction for which one must account. A thinks that B's clock is running slow, and B thinks his own clock is fine. But B also sees the travel as being length contracted, which makes it all consistent. So the travel that takes 45 minutes (75% of an hour) in one frame is only 75% of the distance in the other frame.

[Menoman]

Right, I'm pretty sure I understand that concept.

 

What is getting me, is that in the second graph. I can't see how the times won't be the same. I mean if the clocks B1 and B2 are syncronized perfectly, and to A the time is 1 hour, between B1s passing and B2s passing, it seems that with the synchronized clocks, that time would also be an hour.

 

But obviously since I understand relativity... that cannot be true.

 

I understand that simultaneity is relative as well, so clock A does not see the clocks were actually even syncronized, because in his frame of reference it was not a simultaneous sync. I just can't explain the logic behind that, like i can with the other concepts of relativity.

[swansont]

Oh, the picture wasn't displaying when I posted before.

 

In A's reference frame, you've got the time axis reversed. You still have to go from 12:00 to 12:45 — you don't end up at 12:00