SUN - The Sun is a Star? LESSON

The Sun is a Star?

Without the Sun's energy, we on Earth could not exist. The Sun's ideal balance of heat, visible light, and ultraviolet radiation enabled life to form and flourish here. Compared to other stars, the Sun is a typical star. A star goes through cycles as you will learn later on in Astronomy. Our Sun is considered a main sequence star. To learn more about the Sun's statistics, review the information in the chart below.

Sun Statistics
Term Statistic
Image of the sun. Mass 1.99 x 1030kg
Visual Radius 6.69 x 105 km
Mean Density 1410 kg/m3
Luminosity 3.90 x 1026 J/s
Surface Temperature 5800 K
Central Temperature 15.5 x 106 K
Equatorial Rotation Period 25 days

If you were to compare the mass of the Sun to all the planets in our solar system, you would see that the Sun contains more than 99.85% of the total mass of the solar system. The Sun is also the only star we see during the day. This is due to its proximity in our solar system. The Sun, our closest star, has been burning bright for at least 4.5 billion years and is the source for almost all the energy here on Earth.

Before continuing your training on the sun, learn about the wavelengths of color and how that relates to the sun below. This information will help you in your upcoming lab!

Wavelengths of the Sun

The human eye can only see in a small part of the electromagnetic spectrum called visible light. The Sun and many other objects may give off light that our eyes cannot detect. Infrared is an example of this. Images of the Sun have been taken at the same time but at different wavelengths using the Extreme Ultraviolet Imaging Telescope (EIT). This telescope is attached to a space craft called SOHO (Solar and Heliospheric Observatory) that orbits between Earth and the Sun. This spacecraft is used to observe the Sun and gives warnings of solar storms. In the images below you can see different temperatures in the sun's atmosphere. The colors are not natural; the original black and white photos have had color added to them to help you analyze them.

Red wave 304 A 50,000 degrees celsius, Brown wave 171 A 630,000 degrees celsius. Pink wave 211A 2,000,000 degrees celsius. Green wave 94A 6,300,000 degrees celsius.

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