Flagstaff’s Lowell Observatory And The Legacy Of Pluto

In the early 20th century, an observatory in Flagstaff, Arizona, became the birthplace of one of astronomy's most famous discoveries. Pluto, once known as the 9th planet, was discovered at the Lowell Observatory in Flagstaff, Arizona in 1930. Since Pluto's discovery, the Lowell Observatory has drastically changed the way we see our solar system today.

The Lowell Observatory

The Lowell Observatory was founded in 1894 by a man named Percival Lowell. Lowell was a passionate astronomer who felt Flagstaff was an ideal location for an observatory.

According to the Lowell Observatory, after Neptune was discovered in 1846, astronomers across America theorized the existence of another planet based on the "...apparent irregularities in the orbit of Uranus."

In 1903, Percival Lowell expressed his own thoughts on the hypothetical planet in The Solar System. This book marked the start of Lowell's hunt to find the undiscovered planet. Although Lowell did not live to see his dream come true, his early research paved the way for future astronomers to eventually discover Pluto.

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Pluto's Discovery

The discovery of Pluto is the Lowell Observatory's most famous achievement. Pluto was discovered by Clyde Tombaugh, a young, mostly self-taught astronomer. Clyde became an employee of the Lowell Observatory in 1929. He worked as an assistant and groundkeeper.

According to Earth Sky, on February 18, 1930, after a long day of shoveling snow, Clyde was comparing two photos of a star filed that were taken 6 days apart.  That's when he noticed something peculiar. A faint object was moving amongst the stars. It was the ninth planet the Lowell Observatory had been searching for decades!

Clyde's discovery was made public on March 13th, 1930, and the planet was promptly named Pluto. For more than 75 years, Pluto was recognized as the ninth planet in the solar system, making the discovery a significant moment in American astronomy.

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Pluto Research Today

In 2006, Pluto was reidentified as a dwarf planet by the International Astronomical Union (IAU). The Library of Congress says that this reclassification of Pluto happened because the dwarf planet did not meet the 3 criteria set out by the IAU to be considered a full-sized planet.

Since the reclassification of Pluto, Nasa and the Lowell Observatory have done even more research on it. Data from NASA’s New Horizons mission in 2015 revealed Pluto to be a complex and dynamic planet with mountains, glaciers, an atmosphere, and active geology. It has been discovered that Pluto has 5 moons, and its tallest mountain sits at 9800 feet tall.

Since Pluto's discovery in 1930, the Lowell Observatory continues to play a major role in Pluto research, hosting scientists who study Pluto’s atmosphere, moons, and long-term climate. The observatory is also deeply involved in public education, celebrating Pluto’s discovery each year and preserving the original discovery telescope. Today, Flagstaff is proudly known as the “Home of Pluto,” and the discovery remains a lasting symbol of how careful observation and perseverance can reshape humanity’s understanding of the solar system.

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