The sun is a star! Stars are incredibly hot, enormous balls of plasma. The Sun is an ordinary star, but it is also a huge part of making life on earth possible! The sun gives us heat, energy, and light. The earth is exactly the right distance from earth for life to exist. If we were closer, we would be too hot— further away, we would freeze, and life could not exist.
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Inside the Sun: Core, Radiative Zone, and Convective Zone
The core is in the center of the sun. The sun is a giant heat machine powered by the core. If the sun was a mechanical toy, the core would be like the toy’s battery; except that it would also be 27 million degrees!
The core makes the sun’s energy through a process called nuclear fusion. Fusion is when atoms come so close to one another that they squish (or fuse) together. Atoms are very, very tiny, but they are powerful little things, and they won’t normally ever change their insides. Yet because the sun is so big, it is able to put enough pressure on these atoms that they squish together and become something entirely new! Fusion is sort of like smashing two apples together and the two of them become an orange! The sun isn’t made of apples, though. The sun is mostly made of hydrogen. When hydrogen atoms fuse together, they become helium. Fusion creates incredible energy, and this energy is what fuels the heat of the sun.
The next layer is the radiative zone. In the radiative zone energy from the core “rays” outward by radiation. Do you hear how radiation and radiative sound alike? These rays of light are called gamma rays and x-rays, and they are incredibly powerful. Storytellers often say that gamma rays are what changed ordinary people into superheroes! X-rays are powerful enough to see through your skin so we can take pictures of your bones. These powerful rays of light carry the energy of the sun to the next inside layer of the sun, the convective zone.
The convective zone is where energy boils to the surface of the sun. Convection is when heat rises and cold drops. Think of how a pot of water boils on your stove. First the bottom of the pot gets hot. Then the water on the bottom forms little bubbles. Pretty soon, the water starts bubbling to the surface. As the bubbles rise to the surface of the water, the water that was at the top gets pushed to the bottom so it can heat up too. This boiling action of heat rising and dropping happens in the convective zone where the sun’s plasma boils heat up to the surface of the sun.
Outer Sun: Photosphere, Chromosphere, Corona, Sun Spots, and Solar Flares
The surface of the sun is called the photosphere. The photosphere is 300 miles thick and 10,000 degrees fahrenheit. This is where all the heat from the inside of the sun shines out of the sun as light! This is like the face of the sun. Smile for your photo, sun!
The sun’s surface is very bright, but sometimes the sun will get sun spots. Sun spots are darker, cooler spots on the sun. I think of sun spots like sun freckles, except they form and then go away. These spots form where the sun’s magnetic field is very strong. These cooler spots are a measly 6,500 degrees fahrenheit (which is still incredibly hot!).
There are two layers of light that shine brightly above the photosphere. These layers are the atmosphere of the sun. The earth’s atmosphere is made of the air around us. The sun’s atmosphere is made of gas that burns incredibly hot and keeps us toasty warm on earth.
The chromosphere is the first layer of the sun’s atmosphere. The chromosphere is a reddish layer of gas above the photosphere, and it can be seen during a solar eclipse. The chromosphere has spicules, which are spikes of gas growing up from the surface. Usually when kids draw the sun they also draw the sun’s atmosphere! They draw a circle with lines poking out from the sun, just like spicules! Kids are pretty smart.
The outermost layer of light is the corona. The corona looks like white streamers around the sun, and it can be seen during a total eclipse. Corona means “crown” in Latin, and it is the outermost layer of the sun’s atmosphere. The corona can get as hot as 3.5 million degrees fahrenheit, which is hotter than the surface of the sun!
Sometimes the sun can reach beyond its atmosphere with an exploding solar flare! A solar flare is a giant plume of gas that stretches outside the sun’s magnetic field. These release a lot of radiation into space, and can even interfere with our radio communication on earth!
The sun is incredibly hot, amazingly bright, and overwhelmingly big. It is gives us heat and light, and without it we would freeze in the dark. We can be thankful for the beautiful bright sun that makes life possible.
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