Our closest star, the Sun, one of about 400 billion in our galaxy, the Milky Way. The Sun has extremely important influences on our planet: it controls the climate, ocean currents, seasons, and makes plant life possible through photosynthesis. Without the sun's heat and light, life on Earth would not exist.
But here comes a question: how is this heat produced inside our Sun? And beyond that, what exists inside our star? Because the Sun is our closest star, it has been the target of studies and observations by satellites, telescopes and probes for centuries.
And although it still hides many secrets, we have learned a lot about how this gigantic ball of plasma works, including what happens in its depths. I'm Gabriel Souza and you're very welcome as always. And if you like my videos, consider subscribing to the channel and leaving a like for more content about the universe.
It is impossible to simply look inside the Sun, as there is no technology that can see beyond the thick layers of gas and plasma on the surface. However, using physics and some computer modeling, it is possible to predict the intense internal conditions of the Sun. Furthermore, also observing its atmosphere and its surface, so to speak, facilitates our understanding of the scorching depths of the only star that gives us the life.
On this journey towards the interior of the Sun, we will pass through six layers into which the Sun is divided. The first three are: the corona, chromosphere and the photosphere and are the three outer layers of the Sun. The last three are the Convective zone, Radiative zone and core and are the inner layers of our star.
So we'll start with the Sun's outermost layer, the corona. And in fact, the hottest outside of it. Here we are, the corona, also called the corona.
It is the outermost layer of the Sun and extends 8 million km above the surface and barely appears in our view. One of the techniques for observing it is using X-ray waves. However, the best way to see it is during a total solar eclipse, when the moon blocks almost all the brightness from the Sun's surface so that only a bright ring appears.
This is crown. Remember I said that this is the hottest layer of the Sun outside of it? Well, the temperatures of the solar corona reach up to 2 million degrees Celsius, around 360 times hotter than its surface.
The reason why this region is hotter than the surface of the Sun is still a mystery. After all, in theory, the further away from a heat source, the colder it gets. But the main hypothesis nowadays is that the Sun's magnetic field is somehow influencing the corona and creating temperatures that would kill us in milliseconds.
The second outermost layer of the Sun is called the chromosphere, it is below the corona but just above the photosphere - which I will talk about soon. The chromosphere is 2000 km thick, and it is made up of jets of hot gas that resemble a burning forest. These jets are called Spicules and extend 3 km to 8 km high before collapsing, and last for a maximum of 5 to 10 minutes.
They are probably generated on the surface of the Sun and are ejected at a speed of 20 km/s to the chromosphere. An interesting thing is that the chromosphere has a red color, and this happens because the hydrogen gas in the Sun emits a reddish light at high temperatures. Speaking of temperature, in the chromosphere the temperature reaches 3,700°C.
However, it can get much hotter the closer it is to the crown. But it's time to go much lower. Now we come to the best layer, the photosphere, the lowest layer of the Sun's atmosphere.
Perhaps you know it by the better name of the solar surface. And it is this layer of the Sun that you can see from Earth. The term "photosphere", which comes from ancient Greek, means "sphere of light" and is the layer where most of the Sun's energy is emitted.
It takes about eight minutes for sunlight from the photosphere to reach Earth. The temperature of the Sun's surface can vary, but it will almost always be around 5500°C and it is this temperature that we define as the Sun's standard. We sometimes describe the photosphere as the surface of the Sun.
However, it is not a solid surface like that of rocky planets, such as Earth. It is made entirely of hot, bubbling plasma about 300 miles (482 km) thick. So if you fell here, you would simply sink into this ocean of boiling plasma.
But to be more realistic, you would evaporate. And it is in the photosphere where all the energy and heat produced millions of years ago by its burning core can finally escape into outer space. The photosphere is marked by strange, glowing geometric shapes made of plasma.
These shapes are called solar granules and are formed when heat is transferred from the layer below the photosphere to it. This process can also be called Convection. In addition to them, this is where the darkest and coldest sunspots form , which emerge when the Sun's magnetic field breaks the surface.
Sunspots appear to move across the surface. Observing this movement led astronomers to realize that the Sun also rotates on itself. But now it's time to go deeper, and enter the first of the Sun's three inner layers.
Here we are, in the so-called convective zone. And it is exactly this layer that transfers heat to the photosphere, which ends up creating those granules. Hence the name, convective - which comes from the phenomenon of Convection.
Right below the convection zone, the temperature reaches 2 million degrees Celsius. But the gas present in it tends to cool as it approaches the photosphere. In other words, the deeper you go, the hotter it gets.
The plasma in this layer moves in a convective motion, much like boiling water in a pan, with bubbles of hot plasma carrying heat to the surface. The density of this zone is also very low, which makes it easier for light particles, called Photons, to be converted into heat. But our journey is not over yet, we need to move further.
Just remember what I said: the deeper you go, the hotter it will get. But we will overcome temperatures of millions of degrees and go to the next layer. Below the convection zone is the radiative zone, a region where energy from the Sun's core is transported outward in the form of photons of light, hence the name, radiative zone, because photons of light are a form of electromagnetic radiation.
. This region is not as dense as the nucleus, but it is still dense enough to allow these photons of light to collide with nearby gas molecules. According to NASA, a single photon of light can take more than 100,000 years to leave the Sun's core and reach the surface.
But the funny thing is that this same photon of light only takes 8 minutes to reach Earth. And now, it's time to get to know the restless and violent heart of our star. The heart of our star is its core, a huge nuclear reactor made of hot plasma and possibly 1000 times larger than Earth.
This is where all the energy and heat you receive every day here on Earth is created. To create energy and heat, the Sun's core makes two Hydrogen atoms hit each other violently, and this collision of atoms ends up creating Helium atoms. This is called Nuclear Fusion.
And all of this happens under extreme pressures and temperatures. It is estimated that the temperature of the Sun's core exceeds 15 million degrees Celsius and it is said that the energy released by the core in just 1 second is greater than 1 billion atomic bombs. Well, in this state you have fulfilled your mission, you have reached the core of the Sun.
And just as the particles of light that leave here take 100 thousand years to reach the surface of the Sun, you would be condemned to stay here forever. Since you are not a particle of light that can move at 300,000 km/s, it would take you hundreds of thousands of years to get out of here. End of mission.
