/sci/ - Science & Math

>>6779890
Why... would you need that much accuracy to measure a foot race?
You could do that with a high speed camera and some lasers.

>>6779918
because in principle you could finish a race closer and closer together to the point you would need measurements of larger and larger degrees of accuracy. I guess my question is concerning what happens on a quantum level, assuming the race is that close.

>>6779890
>Lets suppose you have a device that can measure distance to any degree of precision required.
No. lrn2uncertaintyprinciple. The device you propose cannot exist even in principle.

>If two people engage in a foot race, is it possible for them to tie if you have this device handy to measure them at the finish line?
According to who? If they cross the finish at the same time in one reference frame, they will not cross at the same time according to a moving observer.

>>6779924

>precision

Not accuracy

>>6779890

There are two ways to answer this question, with different results, of course. The first way does not take special relativity into account, and the second one does.

First answer: Even armed with such a device, it should be at least theoretically possible for two objects to break the plane of the finish line simultaneously. However you define the distance from the start to the finish lines, and however you define the minimum distance needed for an object to travel that distance, it should be possible for two objects to achieve that distance in the same amount of time, resulting in a tie.

Second answer: I cannot understate how much better a textbook (or even Wikipedia) can explain this than I, but according to special relativity, there's no way say whether two events occur at the same time if those events happen in different places (even very near places). An observer in the same frame of reference as the racetrack might observe a tie, but an observer moving at a very high percent of lightspeed in a direction parallel to the finish line might see one racer cross the finish line first, and another observer traveling the same speed in the opposite direction might observe the other racer cross the finish line first, and none of them would be "right" in an absolute sense. They would all be equally right.

>>6779890
>>6779958

I just visited the wikipedia article, and return with this animated gif that explains... nothing at all, but I guess trust me when I say that simultaneity breaks down at any distance, as evidenced by these blinking dots on a shifting green grid/black background animation...