At the interface of water and air, light can, in certain conditions, bring about evaporation without the need for heat, according to an MIT study.
In a surprising finding, light can make water evaporate without heat::At the interface of water and air, light can, in certain conditions, bring about evaporation without the need for heat, according to an MIT study.
Plants are green specifically because the red and blue wavelengths of light are useful for breaking specific chemical bonds necessary for photosynthesis and as such are readily absorbed by the plant. The plant makes efficient use of the energy provided by only absorbing the wavelengths necessary for its processes. However, plants still absorb 90% of green light and green light holds the highest proportion of the energy radiated by the sun.
To be more clear, green light has too much energy. When plants absorb light it first enters a protein mesh containing pigments such as chlorophyll that function like an antenna or receiver for a range of wavelengths. The pigments then transfer the energy to a "reaction center" where it turns this electromagnetic energy into chemical energy (photosynthesis). This process is exceedingly efficient; almost all of the absorbed energy is converted into electrons the plants can use. However, this protein mesh antenna is not solid and is constantly moving. These movements affect how energy is absorbed and how it flows through the pigments. Think of diffraction in water. Fluctuation in the intensity of light can create noise in this process; a quick brush of shade or sudden increase of light intensity can decrease the efficiency of photosynthesis. For plants and really everything that lives, a steady input and output of energy is desirable. Not enough electrons making it to the reaction center causes energy failure while too much will cause general overcharging effects that can damage tissue. When the noise of this system fluctuates it makes it difficult for the plant to self regulate it's energy flow and could cause the plant to kill it's own tissue or essentially starve. So essentially, while absorbing all green light would provide the plant with more energy, it's not capable of handling this energy so plants evolved to limit their intake of green light.
However, this is not to say that green lights ability to efficiently evaporate water is not a factor in this evolutionary development, hell it's probable that these two things are heavily related. Green light might evaporate water so well because of some combination of its relatively high energy mixed with the size of its wavelength interacting with the hydrogen bonds between water molecules in a more efficient manner than other wavelengths of electromagnetic radiation.
Not a correction but a minor clarification. Green light doesn't inherently have the most energy. Shorter wavelengths have more energy but tend to scatter in our atmosphere and a lot of it doesn't reach the surface (that's why the sky is blue).
It's also why UV light causes skin cancer and burns on humans, and kills bacteria/viruses/etc. Green is also pretty poor at lighting up flourescents, while blue(which has more energy) does much better. Ultra violet is even better than blue.
That does make me question your theory that green light is the most effective at evaporating water because it's high energy. Blue/violet/ultra violet would be better than green if that was the case. The test didn't use sunlight, it used artificial lighting and the effects of the atmosphere are effectively zero over short distances.
Literally yesterday i pitched to my wife that i cant wait till i have some personal drone that ca evaporate and deflect raindrops before they fall on me. Essentially creating a flying rain shield.
Are you meaning using a laser on the drone to evaporate the drops? That causes issues. Though maybe one could just put a waterproof shield on a drone with a particularly strong motor to resist winds, to just act like a regular umbrella that you don't have to carry. Seems impractically noisy and power hungry though
I don’t think i mean all that much. Its mostly a fantasy/dream cause I regularly have to walk through rain.
I am not expecting anything like it in at least 15 years but as fan of the whole “post-scarcity ai automated luxury gay space communism“ i can imagine a few scifi ways to do it like directly shooting individual nano-engineered artificial photons at every single drop that is calculated to otherwise hit me.
Eventually when the cool factor of light umbrellas wears off, traditional retro umbrellas will become cool again. But you can't beat the convenience of light-based rain protection