Radiation Through Vacua

Bruce Herald, Volume XXIV, Issue 2494, 18 July 1893, Page 4

Radiation Through Vacua

' The experiments of Professor Dewar upon the effect of high vacua on the radiation of heat, undertaken in the course of his researches with liquid oxygen, lead to some interesting;considerations that may cause us to modify entirely our conception of radiation of the sun's heat. It has been usually taken that the long heat waves, as well as the short light waves, came direct by radiation from the sun, and that consequently an enormous amount of energy was continually being dissipated. But Professor Dewar's experiment tends to show that an absolute vacuum is entirely impervious to low waves of heat radiation. Interstellar space, therefore, though transparent to light radiation, does not presumably convey heat radiation at all, and the heat waves manifest in the atmosphere are created there. "We see in this the necessity for remodelling our theories upon the time required to cool the earth down ; for, if space is impervious to heat radiation—- as is Professor Dewar's vacuum -rwe need not fear cooling on this account. The interstellar space haß loßt one of its properties, and at- a stroke, by a simple experiment, a huge proportion of the supposed available energy of the lolar system disappears.