There are no wonders in the world, the creatures are even more strange, animals, plants are many will glow, of which the more common is the fireflies, every summer night, they will flash in the jungle or the field, like a little angel, causing people to infinite reverie.
Today, we will understand the luminescence mechanism of this small animal from the perspective of biology, chemistry and physics.
First, the luminous mechanism of fireflies
Simply put, fireflies emit light is a complex biochemical reaction that occurs under the catalysis of fluorescein, and in this reaction process, energy is released in the form of light. That is to say, the light of fireflies, like all light sources in the world, is a release of energy.
There are more than 2,000 varieties of fireflies, different varieties of different forms of light, the color of light is not the same, there are yellow, orange, red, yellow-green and green and other colors of fluorescence, today will not expand on the talk.
Specifically, the glowing part of the firefly is a light emitter in its abdomen, which is composed of light-emitting cells, reflex layer cells, nerve and epidermal cells, and so on. The structure of the light emitter is a bit like the car headlight assembly, the light emitting cells are the bulbs, and the reflective layer cells are like the lamp mirrors and lampshades, which reflect the light emitted by the bulbs in a concentrated manner.
Luminous cells contain two classes of chemicals, one called fluorescein and the other called luciferase. Fluorescein, under the catalytic action of luciferase, chemically reacts with oxygen in the air and releases energy, mainly in the form of fluorescence. Therefore, fireflies emit light as a biochemical reaction.
Why does the glow of fireflies flicker? This is because the fireflies are also breathing, the oxygen transported in the trachea is uneven, when the oxygen is sufficient, the chemical reaction in the luminous cells is strong, the brightness is strong; on the contrary, the reaction is slow, the light will become weaker, or even dull.
In the body of fireflies, there is also a chemical called adenosine triphosphate (ATP), which can regulate the luminous function of fluorescein and re-emit light when the fluorescence is weakened.
The role of fireflies in light is to illuminate their own foraging, second, to intimidate and defend the enemy, and more importantly, to exchange information for the sake of courtship. Adults look for a mate at night by emitting different lights, with males generally glowing for 0.2 seconds and an interval of 2.2 seconds; females responding 0.5 seconds after the male glows.
Second, are fireflies also emitting photons?
Of course, all light in this world is electromagnetic waves, and they are all conducted by photons as a medium. So how many photons can a firefly emit? This starts with the wavelength of visible light.
Visible light is composed of about 7 colors, the wavelength is about 380 ~ 760 nm (nanometer), the wavelength of light of different colors is not the same, the red light wavelength is the longest, the purple light wavelength is the shortest. The light emitted by fireflies has green, yellow, orange, red and other colors or gradients, and the wavelength range from green to red is between 492 and 760 nm.
Let's compromise, averaging 626nm, so we can roughly calculate how many photons the fireflies emit. First, the energy of the 626 nm photon is calculated, and the calculation formula is: E=hc/λ. Here E represents energy; h represents Planck's constant, about 6.626*10^-34J·s; λ is the wavelength of light quantum.
In this way, we can calculate that the photons of 626 nm wavelength are about 3.17*10^-19J (Joule) per energy. So how many such photons can a firefly emit every second? It depends on how much light the fireflies have. After searching for a long time, no data was found specifically on the brightness of fireflies, and only one study believed that 1,000 fireflies was equivalent to the luminosity of a 20-watt light bulb.
The light efficiency of different types of electric lamps is not the same, that is to say, the efficiency of converting the energy of the lamp into photons is not the same, the incandescent lamp is the smallest, the luminous efficiency accounts for only 15% of its energy, and most of the rest of the energy is converted into thermal energy; relatively compared, the efficiency of daylight lighting can reach 50%, and the efficiency of LED energy-saving lighting can reach 90%.
The study did not say that the light emitted by the 1,000 fireflies was equivalent to that of a 20-watt bulb, but generally compared to the bulb, it can only refer to incandescent lamps. According to the incandescent lamp to calculate, the light efficiency of the 20-watt bulb is only 15%, that is, about 3 watts, and the photon energy emitted per second is 3J, so that the photons released at a wavelength of 626 nm per second are about 9.5 * 10 ^ 18.
Divided by 1,000 fireflies, each firefly releases about 9.5*10^15 photons per second, which is 9500 trillion. Quite a few, no wonder the fireflies we see flashing and flashing are very bright.
Some studies believe that the luminous efficiency of fireflies is very high, reaching 88 to 90%, and some say up to 95%, so the energy is rarely converted into heat, and it is a recognized cold light source. The current LED luminous efficiency has reached 90%, which is similar to the luminous efficiency of fireflies, so it should also belong to the cold light source.
Third, the cold light source mechanism of fireflies brings enlightenment to humans
The luminescence principle of cold light source is that under the action of electric field, the electron collision generated excites the fluorescent material and produces a luminescence phenomenon, which has excellent optical characteristics and high luminous efficiency. In general, the cold light source is basically no heat or less heat when working.
The luminous properties of fireflies have brought a lot of enlightenment to human beings, people have successfully extracted fluorescein and luciferase from the glowworm's luminaire, understood its composition through analysis, and then successfully prepared these substances through chemical synthesis methods, applied to light-emitting equipment, greatly improving the luminous efficiency.
Such as fluorescent lamps, neon lights, LCD screens, LEDs, etc., are all cold light sources invented thanks to the inspiration of fireflies. Of course, the cold light source does not produce any heat, but the luminous efficiency is improved very high, such as fluorescent lamps are 35% higher than incandescent lamps, and LEDs are 75%.
But some people believe that the luminous efficiency of fireflies is not as high as previously thought. A research team led by Professor Hideyoshi Akiyama of the University of Tokyo in Japan, by measuring the brightest glowing North American fireflies, found that when its luminous amount is the largest, the light intensity is only 41% of the energy emitted by the luminous substances in the body, which does not have the luminous efficiency of fluorescent lamps.
But fluorescent lamps still have temperature, because there is still a part of the energy converted into heat energy. If the glowworm uses only 41% of the total energy to emit light, but the firefly does not heat up, what is the excess energy converted into? It seems worth further study, and more evidence is needed to speak.
In the animal and plant world, there are many luminous creatures, such as a deep-sea catfish in the ocean, there is a "small lantern" on the head that will emit light; a "moon fish" will also emit light, and some jellyfish will also emit light; and some plants that will emit light, such as "lamp grass", "ghost tree" and so on.
These animals and plants emit light, some like fireflies, with luciferin and photoarabin in the body structure, and some have a special protein in the body. For example, in the body of a luminous jellyfish, there is a protein called Equiline, which emits a bright light when it binds to calcium ions.
After billions of years of craftsmanship, nature has carved animals and plants into extremely fine and perfect, and the mechanisms in them are incomparably complex. With the development of human science and technology today, the imitation of nature is not enough. A very important discipline developed in modern times is called biomimicry, which is to create more exquisite tools or food by figuring out the various mechanisms of the animal and plant kingdoms.
By learning to understand the luminescence mechanism of animals and plants such as fireflies, future light energy technology will become more and more advanced.
Just say this today, welcome to discuss, thanks for reading.
Space-time communication original copyright, infringement and plagiarism is unethical behavior, please understand the cooperation.