The Simultaneity Nature of Relativity
In the post on relativity yesterday we talked about what it is meant to be simultaneous, and now we are going to bring in velocities to make things interesting. As always try and use your imagination to picture this. You are sitting on bench and to your immediate left and right, evenly space away, lightning strikes both point. From your observations both points have been struck by lightning at the exact same time, if you need help visualizing this look at my post on light bulbs from Nov 7.
Now time to change things up a bit, a man in a car was driving by just in front of you, to the left, at the exact same the lightning strikes. He is driving towards the location of the lightning strike on your right and away from the one on your left. Since he is changing his position since the time the lightning strikes have both emitted light then he is going to observe that the lightning that he was driving toward, your right, has been observed before the lightning that he was driving away from, your left.
This shows that the time from which events take place is different for every frame of reference. Relativity takes what Newton said time was, a universal clock, and makes time ‘relative’ to every body of reference.