A new Indiana State Historical Marker recognizes Indiana University astronomy graduates Vesto and Earl Slipher for their scientific achievements in the study of galaxies, Mars and the expansion of the universe.
The marker was installed last month in their hometown of Frankfort. It’s placed in front of Frankfort City Hall, which previously served as Frankfort High School when the Slipher brothers attended.
Vesto earned his bachelor’s and master’s degrees in Mechanics and Astronomy in 1901 and 1903. In 1909 he earned the first Ph.D. in Astronomy awarded by IU. Earl earned his bachelor’s and master’s degrees in Astronomy in 1906 and 1908. Following their education, the brothers embarked on careers in astronomy at Lowell Observatory in Flagstaff, Arizona.
Vesto pioneered the taking of spectra of galaxies, said IU professor of astronomy Catherine Pilachowski. He took spectra of astronomical objects, planets, galaxies, stars and more. This work ultimately led to the discovery that there are other galaxies. Vesto’s data led to the discovery that the universe is expanding, she said.
Spectra, or a spectrum, are like rainbows. A spectrum is a chart or graph that shows the intensity of light being emitted over a range of energies. Astronomers use telescopes to make rainbows of starlight, or rainbows of galaxy light, and those rainbows allow astronomers to study the motions of objects, their velocities and their features in the spectra.
Pilachowski said during the time of Vesto’s work people didn’t know what a galaxy was. There was controversy that “we” were a single large place in the universe with lots of stars and fuzzy nebulae, or “we” were an island universe in a universe that had many other island universes, she said.
“Vesto, the work was significant, highly significant, because it changed our view of what and where we are in the universe,” Pilachowski said. “It changed our understanding of the nature of the universe, the correlation of velocity and distance for galaxies. That led us to understand the expansion of the universe and changed our view of space and time entirely.”
Earl was an astrophotographer. He took about 100,000 photographs of planets, with a focus on Mars. His photographs were used by NASA to help plan some of its first missions to Mars.
“He really established the characteristics of the planets, their nature, what variations we find in those planets,” Pilachowski said. “He really was the master of understanding the solar system and the planets, in particular, during the first half of the 20th century.”
Pilachowski said the state historical marker is important because it demonstrates that Indiana farm boys can grow up to be anything.
“These two farm boys from Clinton County grew up to be some of the world's most famous astronomers,” she said. “They came to IU and got their education. They basically changed our view of the of the world, changed our view of the universe.”
