Our Sun is about five billion years old and accounts for 99.9% of the total mass of this solar system. Most scientists are optimistic that we'll still have a functional sun billions of years from now.

DIAMETER:                                1,390,OOOkmREA:                        
MASS:                                         1.99 trillion, trillion, billion kg    
SURFACE TEMPERA:                5,800 K 
CORE TEMPERATURE:             15,600,000 K
ENERGY OUTPUT:                    386 billion, billion mega watts/second
POWER LEVEL AT EARTH:      1.4 kilo watts / sq meter

Each second about 700,000,000 tons of hydrogen are converted to about 695,000,000 tons of helium and 5,000,000 tons  of energy in the form of gamma rays. As it travels out toward the surface, the energy is continuously absorbed and re-emitted at lower and lower temperatures so that by the time it reaches the surface, it is primarily visible light. 

Even though solar energy is the largest source of energy received by the Earth, its intensity at the Earth's surface is actually very low due to the large distance between the Earth and the sun and the fact that the Earth's atmosphere absorbs and scatters some of the radiation. Even on a clear day with the sun directly overhead, the energy that reaches the Earth's surface is reduced about 30 percent by the atmosphere. When the sun is near the horizon and the sky is overcast, the solar energy at ground level can be negligible. It also varies from one point to another on the Earth's surface. Nevertheless, in the 20th century, the sun's energy has become an increasingly attractive source for small amounts of direct power to meet human needs. A number of devices for collecting solar energy and converting it into electricity have been developed, and solar energy is used in a variety of ways.

Nine quadrillion  (9,000,000,000,000,000) kilowatts/hr. of solar energy fall on the continental United States.  This is the equivalent energy available from 4.25 trillion barrels of oil. The utilization of less than .001% of this renewable resource would satisfy all our energy requirements .

A typical household in the North Eastern part of the United States uses about 2000 gallons of fuel oil per year. A 4X8 collector will harvest about 100 gallons worth of heat in that time period. This means that 20 collectors would be needed to supply all the heating needs. There must be a better way. There is a better way. It's called a solar thermal roof.