National Geographic : 1965 Nov
to collide and fuse. These tiny particles, even in the sun's dense interior, are on the average almost as far apart, in proportion to their size, as the earth and Venus. Moreover, they re quire a head-on crash at extraordinarily high speeds in order to fuse. Human Bodies "Hotter" Than the Sun Only because the sun is so large is its total production of energy so enormous. Poundfor pound, the sun actually produces less heat than the human body. If the mass of the sun could be matched with live bodies and if the normal human metabolism of those bodies could continue, they would generate more heat than the sun now radiates. How do we know this? It's a simple matter of arithmetic: The sun's output of radiant energy, divided by the sun's mass, shows a daily production of two calories a pound. By contrast, the average human body generates something like 10 calories a pound each day. Author Herbert Friedman adjusts the sun-seek ing "eye" of a solar camera in the nose of an Aero bee rocket. At the Naval Research Laboratory in Washington, D. C., where he is Superintendent of the Atmosphere and Astrophysics Division, Dr. Friedman directs the Nation's largest solar rocket astronomy program. His distinguished contribu tions to knowledge of the sun have earned numer ous awards and citations. Cool air, warm swim: Piping water through heat absorbing solar panels on the roof, engineer John I. Yellott (left) raises water temperature some 100 for his pool in Phoenix, Arizona. Mankind is now embarked on a great new adventure-the exploration of space. More than half the scientific satellites launched by agencies of the United States Government are, in one way or another, devoted to the study of the sun's activity and its close relationship to earth's environment. My own agency, the Office of Naval Re search, is deeply involved in studying the sun; we maintain a series of satellites called SOLRAD in orbit at all times for solar radia tion measurements. Until very recently, man's view of the heav ens was seriously hampered by a murky, shimmering atmosphere, which distorts light beams and blots out the sun's atmospheric X rays and much of its ultraviolet and infrared radiation. Henry Norris Russell, the noted Princeton astronomer, once jested, "All good astronomers go to the moon when they die so that they may observe the universe without the interference of a dirty atmosphere."