180 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 192 8 



had the largest circulation of any newspaper in the world at that 

 time. 



In recent years, on account of the failure to find any signs of life, 

 the study of the moon has been rather neglected by the large observa- 

 tories. For many years Mars has held the limelight of public inter- 

 est because of the possibility of life there. Recent observations 

 point to daytime temperatures favorable to life, but the nights are 

 excessively cold. Very meager amounts of atmosphere and water 

 vapor have been observed. In the sun and stars, all of which have 

 immensely high surface temperatures extending fromi 2,000° to 

 25,000° C, there is, of course, no possibility of life, for there all 

 chemical compounds, with few exceptions, are dissociated. In the in- 

 teriors even the atoms are broken up. The astronomer must confess 

 that he can not point with certainty to an}' form of life except on 

 our tiny earth. Nevertheless, much of interest is found in the physi- 

 cal activity of the stars. 



The earliest astronomical discoveries were connected with the 

 bodies of the solar system and their movements, real or apparent. 

 After noting the daily rising and setting of the sun and stars and 

 the monthly changes of the moon's phases and positions, as well as 

 occasional eclijDses and comets, probably the first facts of astronomy 

 to be observed were the motions of the planets and the yearly motion 

 of the sun among the stars. Previous to the invention of the tele- 

 scope some attention was given to the position and brightness of 

 stars, but they were considered to be fixed in position and with few 

 exceptions constant in brightness. 



With the invention of the astronomical telescope by the immortal 

 Galileo, intense interest, such as has never been felt at any otlier 

 time in the history of science, was awakened in astronomy. The 

 theoretical researches of Kepler and Copernicus appealed to a few 

 scientists and philosophers, but actually to see with the eye the 

 Milky Way and star clusters resolved, the spots moving across the 

 face of the sun, the satellites revolving around the planet Jupiter, 

 and to note the changing position of the rings of Saturn were facts 

 of such engrossing interest and concern to everyone that the prevail- 

 ing authorit}' of the church and science were alike shaken to their 

 foundations because at that time they had no room for new facts in 

 their established dogmas. 



The desire to know more of the stars led observers to make increas- 

 ingly accurate records of the positions and the brightness of the 

 stars, which resulted in the discovery that the stars are not at all fixed 

 in position but have individual motions and that some oi" them 

 even varj- in lirightness. These simple observations some 200 years 

 ago were the beginnings of modern observational astronomy. The 

 motions of the stars furnish data for studying the uni'verse as a 



