Teri Miller, age 13, of Indianapolis, Indiana, for her question:

What is the temperature of the sun's core?

Astronomers have instruments that can take the surface temperature of the sun, but none to probe thousands of miles down to its fiery interior. We have only indirect evidence on the temperature of the sun's core. It is estimated by nuclear physicists who know the temperatures necessary to carry on the sort of thermonuclear reaction that apparently goes on in the starry furnace. Naturally they cannot be positive. The most up to date figures are merely estimates and they may be updated on the basis of newer evidence or theories.

At present, most scientists estimate the core of the sun to be at least 20,000,000 degrees centigrade    which equals about 36,000,000 degrees Fahrenheit. It is calculated that this seething temperature is necessary to support the enormous nuclear activity. The surface is much cooler and instruments verify the fact that it varies from place to place. The average temperature is about 5750 degrees centigrade  ¬or over 10,000 degrees Fahrenheit. Vast sunspot areas may be 2,000 degrees centigrade cooler than the average.