phys (0215) - Space: mass dilation

this lesson was actually about simultaneity as well.

an example for simultaneity would be lightning simultaneously striking two sides of the same carriage on a train. an observer would see both bolts of lightning hit either side of the train at the same time.

however a person on the train itself, would see the bolt of lightning on the front of the carriage first, since the light has less area to travel, it arrives sooner.

mass dilation is a strange theory, that only applies when approaching near-light speeds. energy can be converted into mass, and vice versa, so at those kind of speeds, mass would increase making the object heavier, thus slowing it down.

sort of like momentum.. sort of, but for extremely high speeds.