Mark E. Schilling, Age 10, Of Garden Grove, Calif., for his question:
How hot is the middle of the sun?
The surface of the sun is a seething mass of flaming waves, always in a state of uproar and unrest. It erupts in rashes of stormy sunspots, and fiery flames spout up like fountains thousands of miles high. These displays on the surface are caused by the stupend.ous furnace at the center of our starry sun.
The doctor measures the temperature of your body with a thermometer, but no one has used a thermometer to check the temperature of our fiery sun. We must depend upon the astronomers to give us this information. And these experts can only give us estimates. They have instruments to measure how hot it is on the surface of the sun. But when we ask how hot it is in the middle of the sun they can only give us an educated guess.
The sun is a nuclear powerhouse, somewhat like a never ending explosion of hydrogen bombs. The blast furnaces we use to smelt iron and steel are as hot as 1200 degreeb. The surface of the sun is almost 10 times hotter. But compared to the seething heart of the sun, this fiery heat is colder than ice. It is estimated that the core of the sun must be around 27 million degrees centigrade which is more than 22,000 times hotter than one of our hot blast furnaces.
The sun is made entirely of seething gases. The fuel it uses to keep going is hydrogen, and the core is thought to be made of hydrogen gas. Its atoms are stripped of their electrons and become ions. It is under terrific weight and pressure from the outer layers of gases. Some experts think that the hydrogen at the heart of the sun is squeezed or compressed until it is 10 times as dense as heavy steel.
This core of terrific heat and stupendous pressure is the sun's furnace wherc its nuclear power is created. We think we know how the fiery furnace works, and experts suspect what happens step by step. Every second, 564 million tons of hydrogen are rmade into 560 million tons of helium gas. The missing 4 million tons of material is converted, or changed, into seething energy.
Every square yard on the face of the sun pours forth enough energy to power about 500 family cars. Experts can estimate how much nuclear activity is needed to produce this stupendous energy and from this they figure the temperature at the center of the sun. We think that it is as hot as 27 million degrees but it may be quite a lot hotter than this.
We see and feel only the light and heat of the sun. But it also pours forth x rays, rays of ultraviolet and infrared and radio waves. All this radiation is created when particles of matter are changed into energy. Small hydrogen atoms or ions are fused to form larger atoms of helium, but not all the material is needed. These leftover fragments of matter are converted into the radiant energy of the seething sun.