Miles at Chapoquoit - 2021-10-02
Polarized Light
2021-10-04
This image of my friend Miles at Chapoquoit is from two days ago. I don’t use a polarizing light filter because the filter requires adjustment for a particular frame. When I’m photographing the kiteboarders, I’m rapidly and continuously swinging the camera back and forth across the glaring backlight of the western sky at Chapoquoit, trying to follow them as they rip across the waves. I’ve never had any luck with a polarizing filter in that setting.
An article on the Scientific American magazine website by Connie Chang from October 1, 2021, reminded me of my struggles with polarizing filters. Ms. Chang wrote about a recent study by astrobiologists developing an astonishing technology that measures light reflected off Earth’s surface from a helicopter flying far overhead. The scientific instrument they are testing is called “FlyPol,” which analyzes reflected light to study plant life on the ground.
Living things and nonliving things consist of atoms and molecules that have three-dimensional structures. Molecules can exist in two forms that are mirror-images of each other; these are called either right-handed or left-handed. In nonliving objects, according to this article, molecules of a particular type exist as a mixture of right and left-handed forms. But in living things, there is a preference for one or the other state for each kind of molecule. For example, Ms. Chang writes that DNA molecules, which make our genes, are always right-handed, and the amino acids that build our proteins are always left-handed.
These brilliant scientists worked from an understanding that some of the light reflecting off a collection of molecules with the same “handedness” becomes circularly polarized. They designed and built FlyPol to detect the presence of this polarized light when looking at a large patch of ground. By analyzing reflected light from a forest or a grassy Savana, they can assess the health of the plants and identify problems such as drought or infection.
But the same technology, the scientists believe, may ultimately become another tool in the search for extraterrestrial life. Scientists have already learned an enormous amount about other stars and planets by examining light waves that have traveled immense distances across space. The FlyPol technology may one day become a method of scanning for life on distant worlds using a telescope to look trillions of miles out into space.
If we find life on a far-away planet, what kind of life will it be? Will it be something more complex than thick bacterial slime? Will it include intelligent creatures? Will there be kiteboarders?
Monte