One hundred twenty years  ago today, the world got a whole lot smaller.  On this day in 1900, the German theoretical physicist Max Planck gave a lecture to the German Physical Society discussing what was known as "black-body radiation."  What is black-body radiation?  Think of a toaster.  When the coils inside the toaster start to warm bread, they begin to glow bright red.  Before that red warning sign is even visible, electrons on the toaster's surface are being agitated through the heat, and electrons rapidly moving cause a glow.  But a toaster is easy.  Scientists in the 1800s wondered if they could absorb light and heat completely with nothing leaving.  Since nothing can leave, they called the problem "black-body radiation.  What does this have to do with the history of the world?  To extremely simplify, Planck's solution was to realize that he was being limited by classical physics as first laid out by Sir Isaac Newton.  He realized that oscillating electrons could only lose or gain energy in chunks, and he called these chunks "quanta".  And thus, quantum physics was born.  Nobody at the time, Planck included, realized the revolution he was starting.  But five years later, Albert Einstein would use Planck's idea to change the world again.