Planet X, the ex-planet.
On this date in 1930, one of our solar system’s most shy family members, was first discovered.
For billions of years, Pluto had been circling our planet at an unimaginable distance, unknown and unseen to every creature who ever turned its eyes skyward.
But it was there, waiting patiently for an observer to finally pull back the celestial curtains to reveal its existence to a universal audience.
That observer should have been Percival Lowell, a man who proved that with passion, even “bad science” can sometimes lead to good discoveries.
Lowell was a Boston Brahmin who used a large chunk of his family fortune to build an observatory in Flagstaff, Arizona to study the non-existent canals on Mars, which he believed to see through his viewfinder.
Sometime around 1906, Lowell pointed his telescopes farther out into space to search for the elusive “Planet X,” a theorized object whose gravitation was believed to cause a slight tug on the orbits of planets Neptune and Uranus.
For the next 10 years, Lowell spent countless nights scanning the skies, but died of a stroke in November, 1916 at the age of 61 with his dream of discovering Planet X left unfulfilled.
The search for Planet X resumed at Lowell Observatory a decade later when its new director, Vesto Melvin Slipher (a name only Indiana could produce) assigned the hunt to a 23-year-old recent arrival from Kansas named Clyde Tombaugh.
Tombaugh’s job was to photograph the heavens at two-week intervals and to then compare the slides to see if any objects shifted their positions in relation to the background stars. After only a few months, the young man’s work paid off, and a new planet was added to the eight already known. (It was later learned that Lowell had photographed the planet a year before his death, but failed to recognize the discovery.)
The name Pluto, which was suggested by an eleven-year-old English schoolgirl, was eventually selected for the planet, in part because the first two letters, P and L, were Lowell’s initials.
Pluto is nearly 50 times farther away from the Sun than the Earth, and takes over 248 years to complete an orbit. It is so far away from us that it wasn’t even known to have a moon until 1978 (it now has three identified moons).
All was secure in the heavens until 2006 when the International Astronomical Union (IAU) kicked Pluto out of the planetary major leagues, designating it as a “dwarf planet” (shouldn’t it be “little people planet”?). So once again we are back to eight.
Even Percival Lowell’s mistakes proved influential. His incorrect theories about life on Mars still bore fruit in the writings of later science fiction authors. Lowell was later called “the most influential popularizer of planetary science in America before Carl Sagan.”
As it turned out, even “good science” got things wrong in regards to Planet X. After Voyager 2 made a fly-by of Neptune in 1989, it was discovered that the planet’s mass was smaller than first thought. When these new figures were calculated, it was learned that the previously believed discrepancies in the orbits of Neptune and Uranus didn’t actually exist and that there was no gravitational need for the theorized planet. It was simply a coincidence that Pluto just happened to be where Tombaugh was looking.
Had science gotten its numbers right to begin with, no one would have spent the time and money necessary to find Planet X. Had that been the case, Pluto may yet be undiscovered, still silently circling, forever hiding from us all.