Hello, my dear readers!
How your curiosity has been regarding light produced by our sun and other stars? Have you ever thought about how this light is created in the stars?
And how the journey of this light, the photon is from the sun's core to our eyes?
You are most likely to think that the light in the sun is produced through nuclear fusion during which Hydrogen atoms present in the sun's core fuse and release a tremendous amount of energy along with photons and that photon produced is instantly emitted by the sun and reaches to the earth in 8min and then our eyes. But that's not a complete truth! If the photons would be instantly released by the sun then we would have been killed by these photons!! Humanity would have not existed! To know How?? and to find the complete truth for satisfying your curiosity read this blog. In this post, we will see or even experience the photon's journey from the extreme core of our sun to the very sensitive human eye.
So let's get started.
Before we begin our journey as a photon from the sun's core we'll need to know about different (major) layers of our sun.
1. The Core:-
Here hydrogen atoms fuse and emit both tremendous energy and light (photons ) too. From here begins the journey of a photon.
2. The Radiation Zone:-
the innermost Zone or the region between the solar core at 0.2 of the Sun's radius and the outer convection zone at 0.71 of the Sun's radius is referred to as the radiation zone, although the core is also a radiative region..
It is the densest zone in the sun formed of extremely hot and ionized plasma. This zone built by the plasma of superheated hydrogen gas, heated at 700 million degrees. It stretches upto 600,000 km and out of this 600,000kms , 320,000 kmsbare only filled with plasma.
3. The Convection Zone:-
It is the second major layer of the sun. Starting after 0.71 of sun's radius.
It is 200,000 km deep.
4. The Coronal Layer:-
The outermost layer of the sun.
Photon's Journey
1. The Core:-
Here hydrogen atoms fuse and emit both tremendous energy and light (photons ) too. From here begins the journey of a photon.
2. The Radiation Zone:-
If photons would have to directly travel through the layers of our sun "with their usual speed in gases" then the photons would have crossed the sun's boundaries in 2 seconds. But they don't. It takes thousands, lakhs, or even millions of years for a photon to be released from The coronal layer. So something is preventing even light to "escape " well not "escape" exactly. I mean that something is slowing down light (the photons) to so much extend that the journey which light could have travelled in 2 seconds actually takes it thousands of years to do so! No, it's not our sun's gravity that is slowing down photons it is The Radiation Zone of our sun. This Zone as its name suggests is full of radiation and full of fusion activity. As soon as a photon is released from the fusion in the core, it starts heading towards the sun's surface at the speed of light. This, the very photon produced immediately after the fusion is very deadly. Deadly enough to extinguish all life on earth!! Because the photons are nothing but the most energetic form of light, The Gamma Rays. These Gamma rays if hit a human cell, could rupture the DNA apart and destroy the very unit of life. However, these Gamma rays lose a lot of energy in their journey to our eyes. This Gamma-Ray instantly reaches the Radiation zone after its emission from the core. As told earlier Radiation zone is made throughout of plasma, making it the densest layer. Any kind of radiation interacts more with charged atoms like plasma than the neutral atoms, thus, the plasma acts as an opaque layer for photons(Gamma rays ) to pass, making it impossible for the Gamma rays to make it through the radiation zone. In the Radiation Zone, a Gamma-ray is instantly smashed into an ionized gas of plasma atom, then from this plasma atom the Gamma rays are passed to the next and again it is passed to a long series of plasma atoms losing some energy each time the photon is passed to a new plasma atom. Confusing, right? Well, I will make it pretty easy for you. Suppose there are players playing basketball and as the rule, they pass the ball to each other. Now suppose the Ball to be Gamma rays and the players to be superheated and pressurized atoms. The Ball (Gamma-ray) always loses some energy each time a player (an atom in the sun's core ) passes the ball (a Gamma-ray ) to another player(the ionized plasama atom), it loses some energy. You just have to increase the number of players (atoms in the sun's core) to trillions and the ball (the Gamma-ray) to millions. It takes approximately 50 million years for a photon to get rid of passing from atom to atom and cross the radiation zone. After losing so much energy in the radiation zone the photon transforms from the most energetic state of light Gamma Rays to a lower energy state of light called X-rays. Even after this transformation in energy, the photons of x-rays are still not visible. The convection zone makes it visible light.
3. The Convection Zone:-
Opposite to that in the Radiation zone, in this zone the X-rays travel at a superfast speed with only one atom, thus, eliminating the pattern of bouncing from one plasma atom to another. In this zone, a plasma atom rather than just attracting it for some time absorbs it and acts as a taxi for photons to reach the sun's surface. But this taxi too charges the photon for its journey. The plasma atom absorbs little energy from the photon, transforming it into visible light. This zone is home to different activities that are traceable for humans. This zone is too an opaque one. So it can't be seen but can be heard. Nasa's Solar Dynamic Observatories do the job of listening to the Gravitational and infrared waves emitted by the convection zone. But the Convection zone do not end a photon's journey to the surface of the sun. The journey is ended by The coronal zone.
4. Coronal Zone:-
The plasma atom that absorbed the X-ray tries(now transformed into visible light) to get through the Coronal layer of our sun. But here too the photon is impeded by the C.M.E.s and electromagnetic field of the sun. It stays here for at least a week and then it is released from the surface of the sun and is free to move all over the cosmos till infinity.
The Sunspots:-
Apart from the emission of photons another Mind Blowing phenomenon takes place in the coronal zone.
After being emitted from the Coronal layer it takes 8mins 54 seconds for a photon to reach our eyes. when scientists had drawn the picture of infrared radiation of the photon they detected that several regions on the coronal surface were dark.
This means that no light was emitted in those regions. Or light was emitted but something prevented it to escape the coronal surface, it is the enormous twisted magnetic field of the sun that traps the photons into its magnetic force. Not letting the photon to escape the coronal surface. And making it appear darker.
An animation on radiation in the sun
