A few years ago, several staff members at Lowell Observatory responded to an email asking what they viewed as the 10 most important discoveries in the observatory’s history. Among those answering was a member of founder Percival Lowell’s family, astronomers with various research interests, educators, historians and a public relations specialist. Not surprisingly, the results varied widely, not only in items listed, but in the ranking of those items commonly listed. While one person, for instance, rated the discovery of Pluto at the top because of the public awareness about Lowell that it engendered (as well as the addition of a planet to our solar system), another person put the little-known work (in public circles, at least) of 1950s scientist Harold Johnson ahead of Pluto’s discovery because it led Lowell into the modern era of research. The point is, everyone has a different perspective on what is important, so here we will discuss some of the historic scientific research Lowell Observatory is most known for, and then list a few more that are lesser known but still important to the bigger picture.
The discovery of Pluto in 1930
In 1905, Percival Lowell began searching for a theoretical ninth planet in our solar system that he called Planet X. Lowell died in 1916, having come up emptyhanded, but a dozen years later Clyde Tombaugh picked up the search and discovered Pluto in 1930. This put Lowell Observatory and Flagstaff on the map of the world, and this Pluto heritage continues to draw visitors to the observatory.
Percival Lowell popularizing the notion of life on Mars
This crosses the threshold of science into pop culture, but it nonetheless was based on scientific observations and conclusions, incorrect as they may have been. Percival Lowell was a gifted writer and orator who mesmerized people with his provocative ideas of intelligent life on Mars. Long after Lowell’s ideas were disproven, his name is nevertheless commonly brought up in modern scientific discussions of extraterrestrial life.
The first evidence of the expanding universe
Astronomer Vesto Melvin “V.M.” Slipher began working at the observatory in 1902. One of his first projects was to learn how to use a spectrograph, an instrument that, when attached to a telescope and pointed at a celestial object, can allow scientists to determine that body’s composition, as well as if it’s moving away from us or toward us. Over the next decade, Slipher mastered using the instrument and pioneered many new techniques with it. Starting in 1912, he used the spectrograph to observe a number of distant fuzzy blotches and soon realized they were moving at incredible speeds, mostly away from us. These observations helped revolutionize scientists’ understanding of the universe, showing that it must be much older and vaster than previously thought. We now know Slipher was observing what we know today as galaxies and his research findings represented the first evidence of the expanding universe.
Moon mapping in support of the Apollo Missions
This may not head the list in other years, but it certainly does in 2019 as we celebrate the 50th anniversary of the first manned Moon landing. A lot of attention has come to Flagstaff this year because of the role that Flagstaff organizations played in support of the Apollo Moon program. At Lowell, a branch of the U.S. Air Force rented the 24-inch Clark Telescope and, later, the 20-inch Morgan Telescope to create detailed maps of the lunar surface. The second class of astronauts, which includes the likes of Neil Armstrong and Jim Lovell, also visited Lowell during a training trip to Flagstaff.
But that’s not all
Some other notable historic research at Lowell, in no particular order, includes:
- Co-discovery of the rings of Uranus in 1977 by a team of scientists including many from Lowell
- Co-discovery of Pluto’s atmosphere in 1988 by a team of scientists including many from Lowell
- A study of the proper motion of stars (proper motion is the apparent motion of a star with respect to background stars) that lasted from 1957 to 1981
- Longstanding studies identifying and characterizing asteroids and comets
- Carl Lampland’s measurement of the temperature of planets
- Harold Johnson’s development and mastery of the photoelectric photometer in the 1950s—this instrument measures the intensity of light from a celestial object by focusing that light into a photosensitive cell
- Photography of planets begun by E.C. Slipher in the 1900s and continuing into the 1980s by the International Planetary Patrol program at Lowell
- Measuring the positions of double stars
- Art Adel’s pioneering work in infrared astronomy, starting in the 1930s, that included finding windows in Earth’s atmosphere through which infrared radiation could be detected
- Characterizing the long-term variability of Sun-like stars