Neo, don't forget that QM also explains why the universe hasn't gone up in one flash of Ultraviolet light. The first use of QM was by Max Plank. He derived the idea when he was trying to explain why classical physics didn't agree with observation when looking at something that was being heated. Classical theory when applied to a heated body led to the idea that all the energy that went in would immediately be released at extremely high (ultraviolet) frequencies. So the universe couldn't exist. Plank made the unique suggestion that if you assumed that light came in small lumps (quanta) you would be able to match observations to theory. He didn't like it. He considered it to be a mathematical fiction that made theory work, but was not the real world.

Of course then Einstein took his idea and applied it to the photoelectric effect and it explained the observations there too. In fact that was what Einstein got his Nobel for.

So another use of QM is to keep the world from going up in a flash.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.