The Sun
The Sun

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Free course

The Sun

4 course summary

The essential points of this course are as follows.

  1. The Sun is a star, emitting all types of electromagnetic radiation. The light that reaches Earth from the Sun comes mainly from the photosphere, although on its way to Earth it must pass through the chromosphere and the corona. Each of these parts of the Sun shows signs of magnetically driven activity.

  2. Electromagnetic radiation consists of waves that can travel through empty space and cover a huge range of wavelengths.

  3. The Sun is powered by nuclear reactions in its hot core which enable it to release energy steadily over thousands of millions of years. The energy released in the core is transported to the surface by radiation and then convection, passing through radiative and convection zones on the way.

  4. The Sun and the Moon have approximately the same angular size when viewed from the Earth.

  5. The angular size of an object depends on its actual size and its distance from the observer.


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