Introduction

The sun has been producing energy for over 4 billion years, burning at a temperature of 29 million degrees Fahrenheit (Janardhan and Fesmire 2011). With the sun being situated 93 million miles from earth, this means that we are far enough away to benefit from its radiant energy, without being destroyed by it. Our planet is located in the goldilocks zone around our star (NASA 2003). In approximately 5 billion years our star will run out of hydrogen fuel and become a ‘red giant’ destroying planet Earth in the process (Ngo 2010). So, we are technically on borrowed time.

The radiant energy from the sun excites or disturbs electrical and magnetic fields resulting in wave-like activity commonly referred to as electromagnetic radiation. This radiation can be thought of as streams of photons. The shortest waves are gamma rays and they carry most energy and the radiation with the longest waves is radio waves and they carry the least energy (Smithson et al. 2008). Only a small element of this electromagnetic radiation, in the form of light, is visible to the human eye. According to Smithson et al. (2008) it takes 8.3 minutes for energy from the sun to reach us. Most of the radiant energy reaching Earth is transformed into thermal energy by exciting the molecules of matter that make up the atmosphere and the surface of the planet.

When solar energy is absorbed it is converted to thermal (heat) energy. Human populations mostly use this solar energy for heat and electricity. For example Photovoltaic (PV) panels capture sunlight and convert this solar energy directly into electricity. Thermal solar panels on the other hand do not involve converting sunlight to electricity; instead they are used in hot water heating systems or in central heating systems.

The Sun

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