Astrophysicist and director of the Hayden Planetarium, Neil deGrasse Tyson discussed Pluto and the controversy surrounding its demotion from planetary status. He said Pluto was discovered in 1930 by amateur astronomer Clyde Tombaugh, and was thought to have been the long sought-after Planet X. Pluto was even assigned the size and mass that had been presumed for the fabled planet, Tyson added. Astronomers eventually figured out that mistakes in telescope operations had been made and, once accounted for, the need for a Planet X vanished, he further noted.
According to Tyson, the decision to reclassify Pluto's planetary status came about when the International Astronomical Union decided to create an official definition for the term "planet." While Pluto was both gravitationally round and larger than its moons, Tyson pointed out that it did not meet the criterion of having cleared its orbital path. Because of this Pluto was demoted to a "dwarf planet."
Tyson spoke about NASA's Kepler telescope, designed to search for Earth-size planets orbiting other stars. He said if the mission finds nothing, it could mean our solar system is unique in the galaxy. Tyson also explained why there is no need to worry about 2012, the year the Mayan calendar ends and when some people believe a planetary alignment will cause catastrophic changes on Earth. Tyson called the Mayans a "technologically ignorant society" with no insight into the universe, and revealed that the extra gravity caused by the alignment will be insignificant to our planet.