Rainbows Are Much More Than A Pretty View, Here's Why

Rainbows are the subject of much staring and photography, it turns out that observing them also provides a variety of important scientific information.

Different effects viewed in a rainbow can be indicative of atmospheric chemical contamination. There are also implications for engineering efficient combustion engines.

The Institute of Applied Physics at the Technical University of Dresden's Alexander Haußmann added to the body of rainbow research with an article he wrote for European Journal of Physics. Haußmann's article focuses on practical applications of rainbow observation and is directed to sky observers and physics teachers.

Rainbows can give insight into raindrop metrics. This, combined with radar data, can measure how much rainwater reaches the ground.

"If our analysis methods are precise enough, we can turn rainbows into optical remote sensing tools to study the physics of rain," Haußmann said in a release.

"Rain drops are not exactly spherical, but become deformed into slightly flattened 'hamburger bun' shapes due to air drag as they fall through the sky. This has a drastic influence on the appearance of rainbows and makes scattering calculations numerically very demanding."

Using mathematical models to simulate rainbows is a current challenge. The changing shape of raindrops as they fall make it difficult to perform the necessary calculations.

Haußmann's article also acts as a somewhat all inclusive rainbow guide. He begins with the evolution of theories surrounding traditional rainbows.

For the sky observer, Haußmann includes special locations for rainbow observations, as well as rainbow photography tips.

Perhaps the most interesting for the lay person is his incision of nontraditional rainbow types. Twinned rainbows are an uncommon, yet well known and loved sight.

Higher-order rainbows have a tertiary, quaternary, or quinary bow, and were thought to be a myth until recent times. Divergent-light rainbows that occur from non solar sources are an unexpected treat for the casual observer.