How do we measure the distance to a galaxy and why is it so important?
On March 3, 1912, Henrietta Swan Leavitt made a short contribution to the Harvard College Observatory Circular. With it she laid the foundations of modern Astronomy. Locked in solitude due to her deafness, Leavitt was the first person to discover how to measure distance to galaxies, thus expanding our understanding of the Universe in one giant leap.