Basil Mahon Quote
In the Treatise James made an important new prediction from his electromagnetic theory-that electromagnetic waves exert a radiation pressure. Bright sunlight, he calculated, presses on the earth's surface with a force of around 4 pounds per square mile, equivalen to 7 grams per hectare. This was too tiny a value to be observable in everyday life and its detection posed a challenge to experimenters. Eventually, in 1900, the Russian physicist Pyotr Lebedev succeeded, and confirmed James' prediction. Although small on an earthly scale, radiation pressure is one of the factors that shape the universe. Without it there would be no stars like our sun-it is internal radiation pressure that stops them from collapsing under their own gravity. James' discovery also helped to explain a phebomenon that had puzzled astronomers for centuries-why comets' tails point away from the sun.
In the Treatise James made an important new prediction from his electromagnetic theory-that electromagnetic waves exert a radiation pressure. Bright sunlight, he calculated, presses on the earth's surface with a force of around 4 pounds per square mile, equivalen to 7 grams per hectare. This was too tiny a value to be observable in everyday life and its detection posed a challenge to experimenters. Eventually, in 1900, the Russian physicist Pyotr Lebedev succeeded, and confirmed James' prediction. Although small on an earthly scale, radiation pressure is one of the factors that shape the universe. Without it there would be no stars like our sun-it is internal radiation pressure that stops them from collapsing under their own gravity. James' discovery also helped to explain a phebomenon that had puzzled astronomers for centuries-why comets' tails point away from the sun.