Vesto Melvin Slipher and Earl Carl Slipher, two notable alumni of Indiana University, have been honored with a historical marker in their hometown of Frankfort, Indiana. Installed in October, the marker recognizes their significant contributions to astronomy and planetary science.
Vesto Slipher, who received his B.A. in 1901, M.A. in 1903, and Ph.D. in 1909 from Indiana University, was a pioneering observational astronomer. His research on the motion of distant galaxies supported the theory of an expanding universe. Earl Slipher earned his B.A. in 1906 and M.A. in 1908, and became an internationally acclaimed planetary astronomer and astrophotographer.
The marker, placed in front of Frankfort City Hall, highlights the brothers’ journey from rural Indiana to their prominent roles in the scientific community. The building currently serving as city hall was once Frankfort High School, which the Slipher brothers attended before continuing their education at Indiana University Bloomington.
From Bloomington to the cosmos
After joining Lowell Observatory in Flagstaff, Arizona, both brothers made impactful discoveries that enhanced humanity’s understanding of the universe. Vesto Slipher emerged as a key figure in early 20th-century astronomy, making critical measurements that provided evidence for the expanding universe concept. He also explored interstellar gas and dust, later becoming the director of the observatory.
Earl Slipher achieved notable recognition for his detailed photography of planets, especially Mars. Over his career spanning more than fifty years, he captured roughly 100,000 images of Mars and other celestial bodies, helping document seasonal variations on Mars and contributing significantly to the early planning of NASA missions.
Together, the Slipher brothers advanced knowledge in both cosmology and planetary science, with their contributions continuing to affect astronomical research today.
A lasting scientific legacy
Catherine A. Pilachowski, chair of the Department of Astronomy at Indiana University Bloomington, remarked, “The Slipher brothers demonstrated how groundbreaking discoveries can emerge from humble beginnings. Their work transformed our understanding of the universe and our place within it.”
The historical marker stands as a tribute to the Sliphers’ scientific achievements and Indiana University’s role in their formative education. It serves as a reminder of the profound impacts research, discovery, and public higher education can have on shaping future generations of scientists.
As awareness of the Slipher brothers and their work grows, the historical marker will continue to inspire those who learn about their contributions to astronomy.
