Weather-ology: Bridge to the Heavens

by Jaime McLeod | Monday, April 30th, 2012 | From: Weather at Farmer's Almanac

Long before modern science began to understand the processes that create our weather, people made up their own explanations. Many of these accounts were fantastic in nature, with evil or benevolent gods, monsters, and spirits controlling the elements. In this series, we’ll explore some of these ancient myths and share the science behind them. Weather + mythology = weather-ology! I will include more in the future if you are interested.
 
No natural phenomenon captures the imagination quite like rainbows. With their bright colors and ethereal quality, they seem like pure magic, completely removed from the laws of nature. It’s no wonder, then, that rainbows have been the subject of countless myths and legends since the dawn of human civilization.
Chief among rainbow legends is the idea, popular in a wide variety of cultures, that rainbows are actually bridges that link the natural world with the spirit world, or the world of the gods.
One such myth is the Bilröst, a burning rainbow bridge said in Norse legend to span between Midgard, the world of men, and Asgard, the fabled realm of the gods. Its name literally means “shimmering path.”
According to legend, only gods and those killed in battle could cross Bilröst. An ancient prophecy foretold that one day Bilröst would shatter under the weight of Ragnarök, the great war that would bring about the end of the world.
Supernatural as they may seem, though, rainbows are actually created by a perfectly natural process. They form because white light is comprised of all colors of the spectrum. When light passes through water, or glass, it is refracted into its component colors. Rainbows can appear any time there are water droplets in the air and the sunlight shines from behind them at a low angle. That means they are more likely to appear in the early morning or later afternoon. Rainbows always appear directly opposite from the sun.
Even if a rainbow would hold your weight, you would never be able to walk on one anywhere, because rainbows have no set physical location. A person who appears to be standing at the end of a rainbow from another person’s perspective won’t see the rainbow in the same place, but will instead see another rainbow in a different location, opposite the sun.
While you can’t actually cross into Asgard on a rainbow, and you won’t find any pots of gold at the end of one, either, rainbows are still pretty magical, all on their own.