The Sun
What is the Sun?
The sun is a star – just like the ones you see when you look up at the night sky.
How old is the sun?
The sun has been shining for about 4.6 billion years. That’s about 500 million years before the earth was formed.
What makes the sun shine?
The process that makes the sun shine starts at the sun’s center where hydrogen is turned into helium. This is called nuclear fusion and it creates a tremendous amount of energy that is radiated (sent out) into space as heat and light. Nuclear fusion only happens in places that have extremely high pressures and temperatures.
How hot is the sun?
At the center of the sun, the temperature reaches 27 million degrees Fahrenheit.
Will the sun ever stop shining?
Yes, but not for about another 5 billion years. That’s when the sun’s supply of hydrogen, the fuel for nuclear fusion, will run out.
What is solar energy?
Solar energy is created by the sun. During the process called nuclear fusion some matter is lost and goes into space as radiant (or solar) energy in the form of photons. Enough solar energy strikes the U.S. every day to supply the entire earth’s energy needs for a year and a half.
Three Types of Solar
Thermal solar captures sunlight as heat (thermal energy). The heating of swimming pools, using flat plates, is an example of solar thermal energy technology.
Concentrated solar uses lenses or mirrors to concentrate a large area of sunlight (or solar thermal energy) onto a small area. The collected energy may be used to power a cycle that generates electricity. For example, in a concentrated solar power plant, water can be turned to steam to drive a generator.
Solar electric (photovoltaic) converts radiant energy from the sun into direct current electricity, using semiconductors. This type of power generation uses solar panels. The West Tennessee Solar Farm is an example of solar electric (photovoltaic) technology.
