Adriaan Van Maanen (March 31 1884 – January 26 1946) was a Dutch-American astronomer.

In 1911, he came to the United States to work at Yerkes Observatory.

He discovered Van Maanen's star.

He is well known for his measurements of the rotational speed of Spiral nebulae. Being of the belief that nebulae were local, gaseous occurrences that existed in our galaxy, his measurements came to be at odds with Edwin Hubble's discovery that the Andromeda Nebula was a distant stellar object. The speed at which he calculated the nebula to move would have had the Cepheid stars that Hubble had used to calculate the distance rotating at a speed faster than that of light. By 1935 however, it had been determined that Van Maanen's measurements were incorrect.

1884 births | 1946 deaths | American astronomers | Dutch astronomers

Adriaan van Maanen | Adriaan van Maanen | アドリアン・ヴァン・マーネン | Adriaan van Maanen