Welcome to the Solar System! Well, ok, you already know you live here, but how much do you know about our sun and the incredible amount of energy it provides our planet? This Solar Energy FAQ will answer a few of your questions about our sun and about how you can get more out of the energy it provides.
What is the sun made of and how does it work?
The sun contains 99.9% of the mass in the Solar System, and about three quarters of that is hydrogen. The rest is mostly helium. A massive nuclear reaction is taking place constantly in the core of the sun, converting the hydrogen into helium and producing immense amounts of heat and light.
How do we use this solar energy?
As the only planet in the Solar System with life as we know it, our Earth has been using the light and heat of the sun to support plants and animals for as long as life has been here. Plants convert the light from the sun into energy using photosynthesis, a powerful chemical process which takes place in their leaves. Animals eat the plants and thus survive from the solar energy as well, and of course the light enables us to see during the daytime. More recently, human technology has found ways to more directly harness the power of the sun for heat and electrical generation.
About 30% of the light from the sun is reflected away from our planet back into the Solar System. This sounds like a lot, but the sun is providing us so much energy that everything we will ever get from the usual fuels like coal, oil, gas, and uranium only adds up to about half of the energy reaching us from the sun each year. We make use of this energy with technologies such as photovoltaic cells, solar water heaters, and passive heating.
How does this modern technology work?
Probably the oldest method man has used to capture the energy wandering around the Solar System is simple passive heating. This means designing homes specifically to capture as much of the sun’s heat and light as possible. Solar hot water heaters have also been around for quite a while, and can be as simple as a dark-colored tank placed in the sun or can involve complex solar collectors designed to efficiently circulate the water. Photovoltaic cells are the most modern innovation and directly convert sunlight into electricity.
What in the world does “photovoltaic” mean and how do these work?
The name “photovoltaic” comes from the Greek word for “light” and from the name of the electrical pioneer Alessandro Volta, from which we also get the unit “volt” for electrical force. Commonly called solar cells or solar panels, these use semiconductors such as silicon (just like what’s in a microprocessor) to convert light directly into electricity. This technology for harnessing the free energy of the Solar System is advancing rapidly to become cheaper, more efficient, and more durable.