Short answers, pulled from the story.
Clyde Tombaugh spotted Pluto on the 18th of February 1930 using photographic plates at Lowell Observatory in Flagstaff, Arizona. The object had been captured earlier that month on January 23 and 29 but only became visible when Tombaugh used his blink comparator to rapidly switch between images.
The International Astronomical Union reclassified Pluto as a dwarf planet in August 2006 because it failed to clear the neighborhood around its orbit. Pluto's mass is only 0.07 times the combined mass of other objects in its orbit while Earth's mass is 1.7 million times greater than remaining material in its own orbit.
Pluto has an orbital period spanning about 248 years while maintaining a stable 2:3 orbital resonance with Neptune. For every two orbits Pluto completes around the Sun Neptune makes three cycles which last approximately 495 years each.
Sputnik Planitia forms a basin one thousand kilometers wide covered by frozen nitrogen and carbon monoxide ices divided into polygonal cells. These plains contain more than 98 percent nitrogen ice with traces of methane and carbon monoxide dominating the anti-Charon face.
New Horizons made its closest approach to Pluto on the 14th of July 2015 after traveling for 3,462 days across the Solar System since launching in 2006. The spacecraft received its last data bit on the 25th of October 2016 totaling fifty billion bits or six point two five gigabytes.