Annie Jump Cannon — American Scientist born on December 11, 1863, died on April 13, 1941

Annie Jump Cannon was an American astronomer whose cataloging work was instrumental in the development of contemporary stellar classification. With Edward C. Pickering, she is credited with the creation of the Harvard Classification Scheme, which was the first serious attempt to organize and classify stars based on their temperatures. She was nearly deaf throughout her career... (wikipedia)

Classifying the stars has helped materially in all studies of the structure of the universe.
Teaching man his relatively small sphere in the creation, it also encourages him by its lessons of the unity of Nature and shows him that his power of comprehension allies him with the great intelligence over-reaching all.
No greater problem is presented to the human mind.