About the Sun

The Earth orbits the Sun along with the other planets in the Solar System. The Sun is an incredible star. By studying the Sun we can learn more about other nearby stars and their role in the Milky Way Galaxy. Our Sun gives us light, heat and energy. Without the Sun life would not be able to exist on Earth.

Our Sun is very dynamic and is constantly changing. For this reason something interesting is always happening on the Sun. These changes are observed by watching sunspots that are seen on the surface of the Sun. Sunspots increase and decrease in number on a regular cycle of about eleven years on average. The more the sunspots, the more active the Sun is and solar events such as solar flares and coronal mass ejections occur.

The figure on the left shows many sunspots and was taken when the Sun is most active (solar max). The figure on the right was taken when the Sun is less active (solar min). Images courtesy SOHO/NASA/ESA

The Sun is made up of three major interior zones:1. core,2. radiative zone,3. convection zone. Sunspots are observed on the surface of the Sun that is known as the photosphere. Above this layer one finds a narrow layer called the chromosphere where solar flares originate. Finally, the layer of the Sun above the chromosphere where coronal mass ejections can be observed is known as the solar corona.(Courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA)

When the Moon passes in front of the Sun it blocks out the light coming from the photosphere, allowing the light scattered from the solar corona to be viewed. This is known as a solar eclipse and does not occur very often. Therefore special instruments called coronagraphs have been built to view the solar corona. Coronagraphs also block out the light coming from the photosphere. In this way solar events such as coronal mass ejections can be observed (see below). (Courtesy of SOHO/LASCO consortium. SOHO is a project of international cooperation between ESA and NASA.)

Interesting Links

ESA The Sun < http://www.esa.int/esaKIDSen/TheSun.html >

NASA Sun for Kids < http://www.nasa.gov/vision/universe/solarsystem/sun_for_kids_main.html>

Sun|trek < http://www.suntrek.org/ >

Solar StormWatch < http://www.solarstormwatch.com/ >

Windows to the Universe < http://www.windows2universe.org/sun/sun.html&edu=elem >

Stanford Solar Center < http://solar-center.stanford.edu/ >

PROBA2 Science Center < http://proba2.oma.be/ >

Solar-Terrestrial Centre of Excellence < http://stce.be/ >

European Space Agency (ESA) < http://www.esa.int/ >

National Aeronautics and Space Administration (NASA) < http://www.nasa.gov/ >

American Association of Amateur Astronomers < http://www.astromax.org/planets/sun.htm >