ROYGBIV is not the lineup of colors in the rainbow
You probably recall learning the “ROYGBIV” initialism to represent the colors of the rainbow: Red, Orange, Yellow, Green, Blue, Indigo, and Violet. Currently, however, everybody, from students to color experts, has started to ignore indigo. The LGBT Pride flag also has only six colors— and many people are left wondering why indigo, which seems to be just an arbitrary combination of two of the other colors (blue and purple / violet), has found its way into the rainbow.
Well, that’s why we should thank Sir Isaac Newton, a superstitious man who claimed that number seven had a cosmic meaning for the occult beliefs of the time. And he claimed that seven colors, no more, no less, had to come together to make white, and he chose indigo to join the other colors, probably because of the popularity of indigo dye at the time.
Thomas Edison did not invent the lightbulb
Not on its own, anyway. Most historical sources still assume that the light bulb was the work of a group of scientists and that Edison gets all the glory for a few reasons. In 1802, a man named Humphry Davy invented the first electric light, and in 1860, an inventor named Joseph Wilson Swan developed a working prototype of a light bulb utilizing carbonized paper filaments.
Edison, however, rode his coattails in a way and was able to remove some of the technical problems of the previous prototype bulbs in order to make his invention more effective. This was the first “practical and affordable” version, according to Live Science, but it was definitely not the first electric light bulb.