Our solar system no longer has 9 planets. At least 3 generations of Humans have been taught facts about our small slice of the universe that are false. Leave it others more qualified than your scribe to ruminate on the philosophical issues of this decision by Academe. But I would be remiss if I did not observe that the best thing about rigorous scientific inquiry is that facts are continually tested, hypotheses are challenged, and research into known and unknown conditions is continuous.
Courtesy of APOD, we can begin, anew, to familiarize ourselves with the UPDATED solar system and wonder what else is out there.
Eight Planets and New Solar System Designations
Credit: International Astronomical Union
Explanation: How many planets are in the Solar System? This popular question now has a new formal answer according the International Astronomical Union (IAU): eight. Last week, the IAU voted on a new definition for planet and Pluto did not make the cut. Rather, Pluto was re-classified as a dwarf planet and is considered as a prototype for a new category of trans-Neptunian objects. The eight planets now recognized by the IAU are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Solar System objects now classified as dwarf planets are: Ceres, Pluto, and the currently unnamed 2003 UB313. Planets, by the new IAU definition, must be in orbit around the sun, be nearly spherical, and must have cleared the neighborhood around their orbits. The demotion of Pluto to dwarf planet status is a source of continuing dissent and controversy in the astronomical community