Sun

The sun is the star at the center of our solar system. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth.

Structure of the Sun

The sun is composed mainly of hydrogen and helium. It has several layers including the core, the radiative zone, the convective zone, the photosphere, the chromosphere, and the corona.

Core

The core is the innermost layer, where nuclear fusion occurs. The intense pressure and temperature in the core cause hydrogen atoms to fuse into helium, releasing a tremendous amount of energy in the form of light and heat.

Photosphere

The photosphere is the visible surface of the sun. It is the layer that emits the sunlight we see from Earth. It has a temperature of around 5,500 degrees Celsius.

Chromosphere and Corona

Above the photosphere are the chromosphere and corona. The chromosphere is a layer of the sun's atmosphere that is only visible during a total solar eclipse. The corona is the outermost layer of the sun's atmosphere, and it is much hotter than the surface of the sun.

Solar Activity

The sun exhibits various forms of activity, including sunspots, solar flares, and coronal mass ejections. These phenomena are driven by the sun's magnetic field and can have an impact on space weather and technology on Earth.

Effects on Earth

The sun provides the energy that drives Earth's climate and weather. It also sustains all life on our planet through the process of photosynthesis, which is carried out by plants using sunlight to convert carbon dioxide and water into food.

Study Guide

1. What is the sun composed of?
2. Describe the process of nuclear fusion in the sun's core.
3. What are the layers of the sun's atmosphere?
4. Explain the significance of solar activity.
5. How does the sun impact life on Earth?