Science: The Universe at Notre Dame

The sun radiates energy at the rate of about 77,000 horsepower from every square yard of its surface. On the sun there are so many square yards pouring out this energy that little Earth, 93,000,000 miles away, intercepts 127 trillion solar horsepower, and this is only about one-half of one billionth of the total solar energy constantly radiating out into space.

The sun is not "burning"—that is, forming oxygen compounds—but if it were, the equivalent of seven quadrillion tons of coal would have to be consumed every second to maintain its temperature, which is...

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