Our Life-Giving Sun
© Dina Ely
The Sun is actually a star, and even though it seems huge when compared to the planets and other objects in our galaxy, it is actually only a medium-sized star. Just think, there are lots of other stars in the universe that are much bigger than our Sun! (They are, however, so far away from us that they all look like tiny points of light when we gaze into the sky at night.)
Like all stars, our Sun is made up of very hot gases. Our Sun contains mostly hydrogen (which is a vital element to life and the most plentiful element in the universe). The diameter of the Sun (you measure diameter by drawing a straight line from one side of the Sun to the other side) is approximately 1.4 million kilometers, which is incredibly huge by Earth standards! The Earth's diameter is only approximately 12,760 kilometers.
Because the Sun is so big, all of the planets and other objects in our solar system are caught in its orbit. That means everything in the solar system rotates around the Sun. In fact, the very word "solar" means "of or pertaining to the Sun", so solar systems always contain a major star like our Sun!
The Sun regularly gives off "flares", which look like a small arm reaching out from the Sun and lashing out into space. A solar flare is actually an explosion on the Sun. These flares can contain so much energy that an average flare could power the entire United States for two years! When a serious solar flare occurs, excess radiation (radioactive energy) can hit the Earth, causing temporary problems like disruptions of radio waves.
There are dark spots on the Sun which are called "sun spots". The number of suns spots on the Sun changes. The regular changing of sun spots and other activity on the Sun (such as flares) is called the "solar cycle". A solar cycle is approximately 11 Earth years in length.
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