In newtonian physics you learn that momentum is calculated as mass x velocity. Then in modern physics you learn that light has zero mass so you naively assume l

In newtonian physics you learn that momentum is calculated as mass x velocity. Then in modern physics you learn that light has zero mass so you naively assume light has no momentum. Then later you learn that the original equation you learned was missing a piece and light can actually transfer momentum. This is a cool application of that property!