August 12: Otto Struve

Otto Struve

August 12, 1897 – April 6, 1963

Otto Struve was a Ukrainian-Russian-American astronomer who spent most of his life and his entire scientific career in the United States.

Otto Struve was one of the few eminent astronomers in the pre-Space Age era to publicly express a belief that extraterrestrial intelligence was abundant, and so was an early advocate of the search for extraterrestrial life.

He was a member of the Struve family, the son of Gustav Wilhelm Ludwig Struve, grandson of Otto Wilhelm von Struve and great-grandson of Friedrich Georg Wilhelm von Struve, who were Russian astronomers of ethnic German origin. He was also the nephew of Karl Hermann Struve.

He wrote to his uncle Hermann Struve in Germany for assistance, but the latter had died a few months earlier. However, his widow asked her late husband's successor at the Berlin-Babelsberg Observatory to write to the director of Yerkes Observatory in Chicago, Edwin B. Frost, and a job offer soon resulted.

Otto Struve then moved to the United States and began a prominent career in astronomy. He did his Ph.D. dissertation in 1923 and his mother Elizaveta joined him that same year in the US. He became a citizen in 1927 and eventually succeeded Frost as director of Yerkes Observatory. Eventually, he served as director of four different observatories in all, in addition to serving as editor of the Astrophysical Journal and writing numerous books, in addition to his astronomical research. He also served as president of the International Astronomical Union.

Struve's belief in the widespread existence of life and intelligence in the Universe stemmed from his studies of slow-rotating stars. Many stars, including the Sun, spin at a much lower rate than was predicted by contemporary theories of early stellar evolution. The reason for this, claimed Struve, was that they were surrounded by planetary systems which had carried away much of the stars' original angular momentum. So numerous were the slow-spinning stars that Struve estimated, in 1960, there might be as many as 50 billion planets in our Galaxy alone. As to how many might harbor intelligent life, he wrote:

"An intrinsically improbable event may become highly probable if the number of events is very great. ... [I]t is probable that a good many of the billions of planets in the Milky Way support intelligent forms of life. To me this conclusion is of great philosophical interest. I believe that science has reached the point where it is necessary to take into account the action of intelligent beings, in addition to the classical laws of physics."

Otto Struve received the Gold Medal of the Royal Astronomical Society (1944), the Bruce Medal (1948), the Henry Draper Medal (1949), and the Henry Norris Russell Lectureship of the American Astronomical Society (1957)

The crater Struve on the Moon (commemorating three of the Struve astronomers), Asteroid 2227 Otto Struve and the Otto Struve Telescope of McDonald Observatory are named in his honor.