Put your hands in front of your face. For most people, they’ll be mirrors of each other: you can hold them by hand and fit together, but you can’t mount them.
Molecules also show this chirality, or chirality. They are organized into two forms, reversible and non-mountable. It is such a wonderful peculiarity of life that almost all biomolecules will function in only one of their forms.
Natural amino acids – the building blocks of proteins – are often left-handed, or sinistral. On the other hand, natural polysaccharides, such as those that make up RNA and DNA, are almost always right-handed or dextral. If you replace one of these molecules with the other, the entire system collapses.
This abnormality is called homochirality. We’re not sure why this happens, but it’s thought to be an essential characteristic of life. Scientists have now discovered the molecular symmetry of a helicopter flying at 70 kilometers per hour (43.5 miles per hour) at an altitude of 2 kilometers (1.2 miles).
You ask why would they do such a thing? To see if we can detect molecular symmetry on other planets in the search for extraterrestrial life. Even here on Earth, it would be useful to measure this signal from altitude, as it can reveal information about plant health.
“When light is reflected off a biological material, some of the electromagnetic waves of the light will travel clockwise or counterclockwise,” explained physicist Lucas Bate of the University of Bern in Switzerland.
This phenomenon is called circular polarization and is caused by the symmetry of biological matter. A similar chiral nature is not produced from light by a non-living abiotic nature.”
However, as you would expect, this signal is very weak. Circular polarization of plants makes up less than 1% of the reflected light.
One type of instrument that can detect a polarized optical signal is called a spectrophotometer, which uses special sensors to separate the polarized portion. Pat and his team worked for several years on a highly sensitive spectrophotometer to detect the circular polarization of plants. It’s called TreePol and can positively detect circular polarization from many miles away.
Now they’ve adapted TreePol for flights, with improved spectrometers and additional temperature control for optics. This new design is called FlyPol.
When Patty and his team flew the FlyPol over Val-de-Travers and Le Locle in Switzerland, the improvement in these upgrades was immediately apparent.
“The big advance is that these measurements were made in a platform that moved and vibrated and we were still able to detect biometric fingerprints in a matter of seconds,” said astronomer Jonas Kuhn from the University of Bern and the MERMOZ project (Observation Plan, Exterior Modern Non-Metric Surfaces) .
It wasn’t just about FlyPol’s ability to isolate a circular polarizing signal and distinguish it from abiotic surfaces, such as asphalt roads. The team can use it to distinguish between different types of vegetation, such as grass, forests, and even algae in lakes — all from a fast-moving helicopter.
The researchers said this could open up an entirely new way to monitor the health of different plant ecosystems, possibly even coral reefs. But they haven’t finished refining it yet. They want to take it at a speed of about 27,580 miles per hour and an altitude of 400 kilometers – low Earth orbit.
“The next step we hope to take is to make similar discoveries from the International Space Station (ISS), looking at Earth,” said astrophysicist Bryce Oliver Demore of the University of Bern and Mermoz.
At this altitude, the accuracy won’t be good – perhaps 6 to 7 kilometers – but it will help researchers improve the polarization spectrometer and see how well it works at more extreme ranges.
This will allow us to assess the ability to detect biometric fingerprints at the planetary level. This step will be crucial to enabling the search for life in and out of our solar system using polarization.”
The search was published in Astronomy and astrophysics.