HARLOW SHAPLEY

Harlow Shapley 1885-1972

Harlow Shapley was born on a farm, November 2, 1885 in Missouri, USA.
After studying at the University of Missouri and Princeton, he joined the Mount Wilson Observatory in California.
It is the first to realize that the Milky Way is much greater than previously thought and that the place of the Sun in the galaxy is in any place.
Harlow discern the true size of our galaxy in 1918 by studying the globular clusters and to locate the center of our Galaxy.
Shapley estimated the distance of globular clusters based on their angular size of their brightest stars, periods and their apparent brightness of Cepheids.
He discovers that the globular clusters are spherically distributed around a point in the constellation Sagittarius. He then proposed that point as the center of the galaxy, wiping out the heliocentric hypothesis of the time.
Jan Oort then showed that the disk of the Galaxy was rotating around the center, itself located about 30,000 light years from the Sun (1927).
In 1920 he became Director of the Observatory of Harvard College.
In 1925 he began studying the distribution of galaxies in the sky. It is one of the first astrophysicist to believe in the existence of superclusters (which he calls 'clouds' of galaxies), although it does not notice the presence of space between them.
Harlow also discovered in 1938, the dwarf galaxies of the Sculptor and Fornax.

It is on Mount Wilson, Shapley, however, that made his major research, dealing especially to calibrate the period-luminosity relation of Cepheids discovered by Henrietta Leavitt.
His research will take him from 1918 to determine the distance of globular clusters in the Milky Way.
It offers dimensions (inflated) to it, and reveals the position of the galactic center in the direction of Sagittarius, from the eccentric position of the Sun in the Milky Way.
A discovery that will place in the heart of the controversy over the structure of the Universe, which at that time was between astronomers, which is called the Great Debate, whose climax will be a public meeting organized by Hale in 1920 with Curtis.
He died at the age of 86 20 October 1972.

Image: Harlow Shapley conducted research who drive in 1918 to determine the distance of globular clusters in the Milky Way.