Stellar Mass
The next mystery to be addressed by astronomy concerned stellar mass. Henry Russel proposed in 1914 that the hotter, more luminous stars had greater mass, while the cooler stars had a lower mass. This means that the stars on the upper left of the Hertzsprung-Russell diagram had a greater stellar mass and had a blue color, while those on the lower right corner of the Hertzsprung-Russell diagram were red stars with much lower masses. Unfortunately, early in the twentieth century, there was no way astronomers could measure stellar mass. How astronomers figured this out represents one of the greatest accomplishments… Read More »