While researching light, we came across the topic of elementary particles called photons. Light (electromagnetic waves) is a collection of photons. If we think of photons as the smallest unit particle of light, then when light hits something, we can think of it as many photons flying in and hitting it. Also, all objects have temperature, and as a result they constantly emit photons through thermal radiation. Heat = movement of atoms and molecules = generation of electromagnetic waves = generation of photons.
Photons as particles of light
If we count sunlight as photons, it seems that about 1.2 x 1017 photons hit an area of 1 cm2 per second in midsummer, and about 0.06 x 1017 photons hit an area of 1 cm2 per second on a cloudy day. In photosynthesis in plants, one reaction occurs when chlorophyll absorbs one photon, and in the photoreceptor cells of the eye, a reaction occurs when one photon hits the photoreceptor, and light is recognized.
Photons are tiny particles of energy that have no mass and therefore no concept of size. Photons also move at the speed of light from the moment they are generated, and since they have no lifespan, they do not stop until they hit some kind of material. Although they do not have a lifespan, when they hit a material they are absorbed, reflected, or scattered, and when they are absorbed their role is completed.
It also seems to play a role in mediating the attractive and repulsive forces of electromagnetic force, and electromagnetic force is generated by the exchange of photons. The particles that mediate this force are called gauge particles. The photons in this case have a short lifespan and seem to go against the laws of physics, so they are called virtual photons to distinguish them from real photons, which are particles of light. The quantum world makes you feel a sense of wonder.

Photons as energy waves
Unless the experimental environment is special or the energy is high, light seems to pass through even if it overlaps, and it seems to exhibit behavior that is difficult to explain when viewed as a particle. In this case, it is best to think of light as a wave, and when the crests and troughs of the light wave overlap, they are amplified, and when the crests and troughs overlap, they cancel each other out, causing interference, and when it passes through a gap, diffraction occurs, causing the light to go around in a circle.
Also, if we think of light as a wave, we can think of its energy as its frequency. Extremely low frequencies such as 3Hz brainwaves are 10-14eV, 3MHz shortwaves such as radio are 10-8eV, centimeter waves such as 3GHz wireless LAN are 10-5eV, 300THz infrared rays are 1eV, and visible light from 400THz to 790THz is 1.6eV to 3.2eV.
The phenomenon of circular polarization, which rotates in a clockwise or counterclockwise spiral as it moves, and the phenomenon of light refraction and reflection, can both be explained by the characteristics of wave vibration and phase. It’s strange to feel like something is both a wave and a particle.

The mystery of photons
There are many mysteries in the quantum world that deals with photons. If you make two passage holes, interference fringes appear due to the properties of waves, but if you try to confirm which hole the photon passed through, the interference fringes disappear due to the properties of particles. It seems to be a mystery why interference fringes appear again when the record of confirmation is lost. It is also called an observation problem, but does the act of observation have some other meaning?

Regarding this issue, it seems that observational results have been obtained that suggest that it exists in two holes at the same time. It’s as if there is one negative photon in one hole and two positive photons in the other, resulting in a net of one photon. So it’s possible for things to exist in different places at the same time.
ttps://xenospectrum.com/can-photons-exist-in-two-places-at-the-same-time
In addition, photons have a bright, shining state and a dark state (dark photons), and it appears that interference fringes, which were thought to be due to wave properties, can also be explained by particle states. Just because we can’t see them doesn’t mean they don’t exist. This overturns the notion that photons = bright.

light on earth
Thanks to the lack of a photon lifetime, the Earth can receive light from the sun and from distant stars, but it seems that light is also produced on Earth. In addition to the fact that all objects with temperature emit photons, the cells of living organisms seem to emit a faint light. Apparently, the emission of this light stops exactly at the moment of death.

Additionally, bioluminescent organisms such as mushrooms, deep-sea fish, jellyfish, fireflies, and night worms all appear to provide photons to this world.
Photons are amazing
First of all, the quantum world is full of mysteries, but the wonder of the world of photons makes me feel the amazing mechanism of this world. I’ve seen the expression that all matter is light, and it seems to be so closely related to the existence of matter that it makes me think so. I think beauty exists because of light, and light is an amazing phenomenon. Photons are amazing. It’s amazing that the Earth is filled with photons from living organisms.