PSAT Writing and Language Practice Question 655

Question: 655

Pluto
"My very educated mother just served us nine pizzas" is 12 a sentence, that may not mean much to young students anymore. However, to people of an older generation this sentence is almost universally recognized as a mnemonic device used to aid children in remembering the planets of our solar system. The sentence has changed recently, not because serving nine pizzas is against school lunch health standards, 13 but because the planets themselves have changed. 
In 2006, 14 despite public outcries and complaints, scientists reclassified Pluto, effectively removing "pizzas" from the well-known memory aid. Pluto, discovered in 1930, had long been viewed as the adorable kid brother of the solar system, significantly 15 smallest than the older siblings and tagging along at the back of the line. That ended when several other similar sized planets were discovered in Pluto's orbit. The discovery of these smaller planets 16 were the beginning of Pluto's demise.
The issue with these smaller celestial objects was whether they could really be classified as planets. Many scientists wanted all of the smaller objects to be planets so that Pluto could remain one as well; 17 however, this proved to be impractical, as it would have resulted in objects smaller than our moon being planets. The International Astronomical Union, an organization that long has been in charge of classifying and naming celestial bodies, set about to solve the problem by clearly defining what a planet is. 18 Their goal was to give the criteria for what makes something a planet. Their proposal held that objects that were in orbit around the sun (but not around another planet) 19 were quite large and had a resulting large amount of gravitation, could be considered planets. Unfortunately, Pluto didn't meet these stipulations.
While Pluto is in orbit around the sun and has become nearly round, it isn't big 20  enough, and therefore doesn't have enough gravity, to clear its orbit. This is proved by the fact that many of those other small planet-like objects have been discovered in Pluto's orbit. Together, these objects now make up what has been named the Kuiper belt. They have each been classified as dwarf planets, meaning that they meet most, but not all, of the qualifications of a full-sized planet. 21 Because most of the world has come to accept that Pluto is no longer a planet, some people remain stubbornly attached to their older, nostalgic views of the solar system. 22 It is truly a shame that people cannot give up their old-fashioned views on what constitutes a planet.

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