American astronomer, born at Wilton (New Hampshire) on May 31, 1872, and died in Riverdale (Maryland) on December 17, 1973, famous for his work on solar energy and the influence of this on terrestrial temperatures.
He studied at the Massachusetts Institute of technology, where he graduated in 1895, and he was then appointed Assistant to Samuel p. Langley, director of the Smithsonian Astrophysical Observatory. His entire career was developed in this institution, which helped give great prestige. He collaborated with Langley in the study of the infrared portion of the solar spectrum, as well as measurements of the solar constant of radiation, the amount of solar energy that the Earth receives. In 1907, after the death of Langley, he assumed the leadership of the Observatory, and suggested further measurements of the solar constant and its cyclical variations. He noted that these variations occur when radiation enters the Earth's atmosphere, fact checked by measuring at different heights of the atmospheric layer; He studied the influence of these variations in the climate, which was crucial for a better understanding of long-term weather predictions; also in the own solar cycles, as well as in the process of photosynthesis.
In 1897 he contracted marriage with Lillian E. Moore, which widowed in 1944, and in 1954 returned to marry Virginia A. Johnston. From 1928 to 1944 he was Secretary of the Smithsonian Institution, in which happened to Charles D. Walcott, and from that office created the Division of radiation and agencies, later biological laboratory of radiation. Interested in aviation development, said a long controversy with Orville Wright, aviation pioneer, in support of the prototype designed by Langley. His main works were El Sol (1911), the Earth and stars (1925), the Sun and the welfare of man (1928) and great inventions (1932).