Clyde Tombaugh, American astronomer and academic, discovered Pluto (b. 1906)

Clyde William Tombaugh (February 4, 1906 – January 17, 1997) was a distinguished American astronomer whose meticulous sky surveys fundamentally reshaped our understanding of the outer Solar System. Born in Streator, Illinois, Tombaugh was largely self-taught in astronomy, building his own telescopes before gaining professional recognition, a testament to his dedication and observational skill.

The Seminal Discovery of Pluto

Tombaugh's most celebrated achievement came on February 18, 1930, when, at the age of 24, he discovered Pluto. This landmark finding occurred during his tenure at the Lowell Observatory in Flagstaff, Arizona, where he was tasked with systematically searching for "Planet X," a hypothetical ninth planet whose gravitational pull was believed to be influencing the orbits of Uranus and Neptune. This quest was initiated by the observatory's founder, Percival Lowell.

Using a blink comparator, a device that allowed him to rapidly alternate between two photographic plates of the same region of the sky taken a few days apart, Tombaugh painstakingly examined millions of stellar images. He identified Pluto as a tiny, moving point of light against the static background of distant stars, confirming its planetary nature at the time.

Pluto's Evolving Status and the Kuiper Belt

Upon its discovery, Pluto was hailed as the Solar System's ninth planet. This classification held for 76 years. However, advancements in astronomical observation, particularly the discovery of numerous other icy bodies beyond Neptune, many comparable in size to Pluto (such as Eris, discovered in 2005), led to a re-evaluation of its status. In 2006, the International Astronomical Union (IAU) formally reclassified Pluto as a "dwarf planet." This decision was based on the IAU's new definition of a planet, which requires an object to have "cleared its orbit" of other debris – a criterion Pluto does not meet within the crowded region now known as the Kuiper Belt.

Significantly, Pluto was the very first object discovered within this vast, donut-shaped region of icy bodies extending beyond Neptune's orbit. Tombaugh's discovery thus provided the initial empirical evidence for the existence of the Kuiper Belt, a concept theorized by astronomers like Gerard Kuiper and Kenneth Edgeworth decades before its extensive population was confirmed.

Beyond Pluto: A Broader Astronomical Legacy

While Pluto remains his most famous discovery, Tombaugh's contributions to astronomy extended far beyond this single finding. During his extensive sky surveys, he discovered a remarkable 14 asteroids (now officially categorized as minor planets). His work also led to the identification of several star clusters, a comet, and numerous variable stars, underscoring his extraordinary observational prowess and dedication to mapping the cosmos.

Advocacy for Unidentified Flying Objects (UFO) Research

Intriguingly, Tombaugh was also a prominent voice advocating for serious scientific research into unidentified flying objects (UFOs). He maintained a professional, data-driven perspective, asserting that while many reported sightings could be explained by conventional phenomena, a small percentage remained genuinely unexplained by current scientific understanding. He firmly believed that these anomalous observations warranted rigorous, unbiased scientific investigation, emphasizing that dismissal without proper study was unscientific and counterproductive. His stance highlighted his commitment to empirical evidence and inquiry, even concerning unconventional topics.

Legacy and Impact

Clyde Tombaugh passed away on January 17, 1997, at the age of 90. His ashes were notably sent into space aboard the New Horizons spacecraft, which flew past Pluto in 2015, fulfilling a poignant wish. Tombaugh's legacy is immense; he not only expanded our Solar System by discovering Pluto but also pioneered systematic sky surveys that laid the groundwork for future discoveries of trans-Neptunian objects. His name is etched into astronomical history, not only through his discoveries but also through the asteroid 1601 Tombaugh, named in his honor. His dedication to observational astronomy continues to inspire new generations of scientists.

Frequently Asked Questions About Clyde Tombaugh and Pluto

When did Clyde Tombaugh discover Pluto?

Clyde Tombaugh discovered Pluto on February 18, 1930, while working at the Lowell Observatory in Flagstaff, Arizona.

Why was Pluto reclassified as a dwarf planet?

Pluto was reclassified as a dwarf planet by the International Astronomical Union (IAU) in 2006 because it did not meet the new criterion for a full-sized planet: it had not "cleared its orbit" of other significant debris. This reclassification followed the discovery of many other similar-sized objects in the Kuiper Belt.

What else did Clyde Tombaugh discover besides Pluto?

Beyond Pluto, Clyde Tombaugh discovered 14 asteroids, numerous star clusters, variable stars, and a comet during his extensive sky surveys.

What was Clyde Tombaugh's view on UFOs?

Clyde Tombaugh was a proponent of serious, unbiased scientific research into unidentified flying objects (UFOs). He believed that genuinely unexplained sightings should be thoroughly investigated rather than dismissed.