The Search for Planet X
A rich astronomer spent his last years hunting for an unseen Planet X. After he died, a young farm boy from Kansas, hired to keep looking, found something.
What was reported
Percival Lowell, the astronomer who believed in canals on Mars, was convinced that another planet lay beyond Neptune, which he called Planet X. He searched for years at his observatory in Flagstaff, Arizona, but died in 1916 without finding it.
In 1929, the observatory hired Clyde Tombaugh, a 23-year-old from a Kansas farm with no university degree, who had impressed them with his drawings of planets. Comparing photographic plates night after night, on 18 February 1930 he spotted a faint dot that moved. It was named Pluto.
Explanations offered
Pluto turned out to be far too small to cause the effects Lowell had calculated, which later proved to be errors in the measurements. Its discovery was partly luck. In 2006, Pluto was reclassified as a dwarf planet, one of many icy worlds in the Kuiper Belt. Some of Tombaugh's ashes flew past it aboard the New Horizons probe.
- When
- Found on 18 February 1930
- Where
- Lowell Observatory, Flagstaff, Arizona, USA
- Witnesses
- Clyde Tombaugh and Lowell Observatory
- Status
- Partly explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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