How long have you spent thinking about rainbows—like really thinking about them? National Geographic reports atmospheric scientists Jean Ricard has spent enough time thinking about rainbows to develop a new rainbow classification system, which he presented Friday at an American Geophysical Union meeting. According to the presentation, Ricard created the system—which puts rainbows into 12 categories—because the classic ROY G. BIV rainbow described by textbooks hardly ever exists in nature. Rainbows are actually more complex than that. Ricard and his team found that rainbows can have up to four characteristics: the main band, a fainter double rainbow, a dark space between the two, and any additional bands, Live Science reports.
National Geographic reports things get complicated because of all the variables—hence the 12 categories. For example, some rainbows exclude entire colors. Not to mention rainbows are constantly changing. "They don't look alike because when we look at a rainbow, one second later, the drops which form the primary bow and the secondary bow are not the same, because they are falling," Live Science quotes Ricard as saying. For decades scientists had been classifying rainbows based on raindrop size, according to the presentation. But after studying hundreds of pictures of rainbows, Ricard found the height of the sun actually has a bigger effect. National Geographic reports classifying rainbows might seem like a "frivolous endeavor," but Ricard says it can "challenge our understanding of rainbows." (Did the Grateful Dead conjure a rainbow?)