Layers of the Sun

Layers of the Sun The Core: The core makes up 10% of the inner most part of the Sun and consist mostly of plasma. With temperatures as high as about 15 million K, the 92% of hydrogen that makes up the sun fuses into helium. With each reaction, mass is converted into energy. This process is called thermonuclear fusion. This fusion is what accounts for all of the energy emitted by the Sun. The Radiation Zone: This layer of the Sun surrounds and acts as an insulator for the core. The radiation zone is where energy transport occurs from the core. Energy particles formed in the core become photons. These photons quickly bounce around the sun slamming into nearby ions, which results into the ion moving into an upward direction at a very high speed. This process continues to repeat itself, making this zone the dominant means of outward energy flow, about 70% of the way out to the photosphere. The Convection Zone: Surrounding the radiation zone is the convection zone. The convection zone is the outermost layer of the interior of the Sun. It is much cooler and less dense than the other layers, however, the convection that occurs here is what brings heat to the surface of the Sun. Convection is the transfer of energy by moving currents of gas (or fluids) containing that energy. Once convection occurs, hot plasma rises then cools as it nears the surface and falls to be heated then rises again. The Photosphere The photosphere is the innermost layer of the Sun’s three layers that make up its atmosphere. It is the layer of the sun that is visible to us. The energy production that occurs between the core, radiation zone, and the convection zone is released as light. In fact, light from the photosphere reaches Earth in about eight minutes. Looking at the photosphere under a telescope, you can see blotchy, dark edged regions called granulation. These granules are the cause of the convection currents happening in the convection zone. Another feature of the Sun’s photosphere is its sunspots. This region of the photosphere occur by themselves but on occasion arrive in clusters. Their dark appearance is because they are cooler than the rest of the Sun’s lower atmosphere. It was observed that these sunspots also appeared to move across the Sun’s disk, leading astronomers to realize that the sun rotates on its axis. The Chromosphere This layer is the second most outer layer of the Sun lying between the photosphere and the corona. Although its name translates to “sphere of color,” its low density makes this layer transparent and only visible when the photosphere is blocked during a solar eclipse, which it then emits a reddish glow. The chromosphere layer has numerous spikes of jets of gas called spicules. Spicules occur when hot gas in and below the photosphere get trapped by the Sun’s magnetic field. The neutral gas pulls upward on the magnetic field trapping it, where it is then forced open and all the trapped gas escapes, all lasting for about five to fifteen minutes. The chromosphere may play a role in conducting heat from the interior of the Sun to its outermost layer, the corona. The Corona This outermost region of the Sun, much like the chromosphere, can only be seen when the photosphere is blocked out. Although it has extremely high temperatures at about 2 million K, the density of the corona is very low, accounting for its dimness. The reason for the corona’s very high temperatures is still being researched, however, what has been discovered so far is that the corona contains several highly ionized elements, the hotter a gas, the more it is ionized. The Sun’s gravity, much like the Earth’s, works to keep its outer layers from escaping. However, some gases are moving fast enough to escape, a portion of these gases coming from the corona. This outflow of particles creates a solar wind. Affected by the Sun’s magnetic field, the corona is continually changing in size and shape.