large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_02_asimov_64kb_47
large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_02_asimov_64kb
English
12904
Helmholtz calculated that the sun's contraction over the 6000 years of recorded history would have reduced its diameter only 560 miles—a change that would not have been noticeable to the unaided eye. HELMHOLTZ CALCULATED THAT THE SUN'S CONTRACTION OVER THE SIX THOUSAND YEARS OF RECORDED HISTORY WOULD HAVE REDUCED ITS DIAMETER ONLY FIVE HUNDRED SIXTY MILES A CHANGE THAT WOULD NOT HAVE BEEN NOTICEABLE TO THE UNAIDED EYE
t and light since the days of the pyramids, let alone since the days of the dinosaurs. Was there some source of energy greater than chemical energy? What about the energy of motion? Helmholtz suggested that meteors might be falling into the sun at a steady rate. The energy of their collisions might then be converted into heat and light and this could keep the sun shining for as long as the supply of meteors held out—even millions of years. This, however, would mean that the sun’s mass would be increasing steadily, and so would the force of its gravitational pull. With the sun’s gravitational field increasing steadily, the length of earth’s year would be decreasing at a measurable rate—but it wasn’t. In 1854 Helmholtz came up with something better. He suggested that the sun was contracting. Its outermost layers were falling inward, and the energy of this fall was converted into heat and light. What’s more, this energy would be obtained without any change in the mass of the sun whatever. EAT AND LIGHT SINCE THE DAYS OF THE PYRAMIDS LET ALONE SINCE THE DAYS OF THE DINOSAURS WAS THERE SOME SOURCE OF ENERGY GREATER THAN CHEMICAL ENERGY WHAT ABOUT THE ENERGY OF MOTION HELMHOLT SUGGESTED THAT METEORS MIGHT BE FALLING INTO THE SUN AT A STEADY RATE THE ENERGY OF THEIR COLLISIONS MIGHT THEN BE CONVERTED INTO HEAT AND LIGHT AND THIS COULD KEEP THE SUN SHINING FOR AS LONG AS THE SUPPLY OF METEORS HELD OUT EVEN MILLIONS OF YEARS THIS HOWEVER WOULD MEAN THAT THE SUN'S MASS WOULD BE INCREASING STEADILY AND SO WOULD THE FORCE OF ITS GRAVITATIONAL PULL WITH THE SUN'S GRAVITATIONAL FIELD INCREASING STEADILY THE LENGTH OF EARTH'S YEAR WOULD BE DECREASING AT A MEASURABLE RATE BUT IT WASN'T IN EIGHTEEN FIFTY FOUR HELMHOLTZ CAME UP WITH SOMETHING BETTER HE SUGGESTED THAT THE SUN WAS CONTRACTING ITS OUTERMOST LAYERS WERE FALLING INWARD AND THE ENERGY OF THIS FALL WAS CONVERTED INTO HEAT AND LIGHT WHAT'S MORE THIS ENERGY WOULD BE OBTAINED WITHOUT ANY CHANGE IN THE MASS OF THE SUN WHATSOEVER
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