Planet X

[(David P.)]

[...]
Tombaugh's task was to systematically image the night sky
in pairs of photographs taken two weeks apart, then examine
each pair & determine whether any objects had shifted position.
Using a machine called a blink comparator, he rapidly shifted
back and forth between views of each of the plates, to create
the illusion of movement of any objects that had changed
position or appearance between photos. On Feb 18, 1930, after
nearly a year of searching, Tombaugh discovered a possible
moving object on photographic plates taken on Jan 23 & Jan 29
of that year. A lesser-quality photo taken on Jan 21 helped
confirm the movement. After the observatory obtained further
confirmatory photos, news of the discovery was telegraphed to
the Harvard College Observatory on March 13, 1930.

The discovery made headlines across the globe. The Lowell
Observatory, who had the right to name the new object, rcvd
over 1000 suggestions from all over the world, ranging from
"Atlas" to "Zymal". Tombaugh urged Slipher to suggest a name
for the new object quickly before someone else did. Constance
Lowell proposed Zeus, then Lowell, and finally her own first
name. These suggestions were disregarded. The name "Pluto"
was proposed by Venetia Burney (later Venetia Phair), an
eleven-year-old schoolgirl in Oxford, England. Venetia was
interested in classical mythology as well as astronomy, and
considered the name, one of the alternate names of Hades, the
Greek god of the Underworld, appropriate for such a presumably
dark and cold world. She suggested it in a conversation with
her grandfather Falconer Madan, a former librarian of Oxford
University's Bodleian Library. Madan passed the name to Prof.
Herbert Hall Turner, who then cabled it to colleagues in
America.

The object was officially named on March 24, 1930. Each member
of the Lowell Observatory was allowed to vote on a short-list
of 3: "Minerva" (which was already the name for an asteroid),
"Cronus" (which had garnered a bad reputation after being
suggested by an unpopular astronomer named Thomas Jefferson
Jackson See), and Pluto. Pluto received every vote. The name
was announced on May 1, 1930. Upon the announcement, Madan
gave Venetia 5 pounds as a reward. The name was soon embraced
by wider culture. The Disney character Pluto, introduced in 1930,
was named in the object's honour. In 1941, Glenn T. Seaborg
named the newly created element plutonium after Pluto, in
keeping with the tradition of naming elements after newly
discovered planets, such as uranium, which was named after
Uranus, and neptunium which was named after Neptune.
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