Our Sun

INTRODUCTION: The sun is the most important star on our solar system. Not only because it is the largest object, but becauseit contains 98%of the total solar system mass.Did you know that one hundred and nine earths would be required to fit across the sun's disk, and it's interior itself could hold over 1.3 millon earths. The photosphere is the sun's outer visible layer, and has a temperature of 6,000 degrees Celsius. Due to the turbulent eruptions of energy at the surface, this layer has a mottled appearance.
Deep within the core of the sun is where solar energy is created. It is at the core of the sun that the temperature (15,000,000 degrees Celsius) and pressure (340 billion times earth's air pressure at sea level) is so intense that nuclear reaction take place. Through a process known as convection, the difference in mass is expelled as energy is brought to the surface of the sun, where it is released as light and heat. The energy that is generated in the sun's core takes one million years to reach it's surface. Every second there are 700 million tons of hydrogen that are converted to helium ashes. During this process 5 tons of pure energy is released. In other words, as time passes the sun is becoming lighter.
The chromoshere is located above the photosphere. Solar energy passes through this region on the sun on it's way out from the core of the sun. Arising from the chromosphere there are faculae and flares. Faculae are the bright luminus hydrogen clouds which form above regions where sunspots are about to form. Flares are bright filaments of hot gas emerging from sunspot regions. Sunspots are dark depressions on the photosphere with a temperature of 4,000 degrees Celsius.
The corona is the outer part of the sun's atmosphere. Prominences appears in this region. Prominences are immense clouds of glowing gas that erupts from the upper chromosphere. On the other hand, the outer region of the corona stretches far out into space and consists of particles traveling slowly away from the sun. The corona of the sun can only be seen during total solar eclipses.

The sun seems to have been active for 4.6 billion years and can go on for another 5 billion years. At the end of its life, the sun will start to fuse helium into heavier elements and begin to swell up, and by growing so large that it will swallow the Earth. After 1 billion years as red giant, it will collapse into a white dwarf. The final end product of a star like ours. It may take one trillion years for our sun to cool off completely.

This page was written by Deborah Sicard in the Astronomy class of BCC/Broward county July 1998