When Is a Planet Not a Planet?: The Story of Pluto by Elaine ScottSpace and planets are topics of endless fascination to kids and part of every grade-school curriculum. Yet because of the history-making reassignment of Pluto from “planet” to “dwarf planet” on August 24, 2006, all books on the solar system are now out of date.
Enter When is a Planet Not a Planet? The Story of Pluto by Elaine Scott, an esteemed writer of non-fiction for children. Scott is the first to put the answer to the title question into terms simple enough for a very young audience to understand, based upon the new definitions determined by the International Astronomical Union.
Well-researched and accompanied by large, awe-inspiring photographs and paintings, this exciting new book makes clear what astronomers have argued about for decades.
Why Pluto is No Longer a Planet
Pluto minor planet designation : Pluto is a dwarf planet in the Kuiper belt , a ring of bodies beyond Neptune. It was the first Kuiper belt object to be discovered and is the largest known plutoid or ice dwarf. Pluto was discovered by Clyde Tombaugh in as the ninth planet from the Sun. After , its status as a planet was questioned following the discovery of several objects of similar size in the Kuiper belt. That definition excluded Pluto and reclassified it as a dwarf planet. It is the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris.
Since its discovery in , Pluto has been a bit of a puzzle:. These facts contributed to the long-running debate over whether to consider Pluto a planet. On Aug. The first of these resolutions was Resolution 5A, which defines the word "planet. Pluto is relatively round and orbits the sun, but it does not meet the criteria because its orbit crosses Neptune's orbit. Critics of the resolution argue that other planets in the solar system, including Earth, have not cleared the neighborhood around their orbits. Earth, for example, regularly encounters asteroids in and near its orbit.
On many of our daily astronomical tours , it is common for some people ask whether Pluto is a planet or not? Today in our blog we give you the keys to understanding this… astronomical confusion. Pluto was discovered in in the United States and this is precisely one of the first keys to the affair:. Remember that the classical planets, those visible to the naked eye Mercury, Venus, Mars, Jupiter and Saturn have been known for centuries and centuries, so it is not possible to attribute their discovery to a particular person. It was clear that it was tiny, which broke the original idea that our Solar System was organized in such a way that the small, rocky planets were near the Sun and the gaseous giants were further away.
Try It Out
All rights reserved. Pluto has been voted off the island. The distant, ice-covered world is no longer a true planet, according to a new definition of the term voted on by scientists today. In a move that's already generating controversy and will force textbooks to be rewritten, Pluto will now be dubbed a dwarf planet. But it's no longer part of an exclusive club, since there are more than 40 of these dwarfs, including the large asteroid Ceres and UB, nicknamed Xena—a distant object slightly larger than Pluto discovered by Brown last year.
By now you have probably heard that Pluto is no longer a planet. But why is that? What did it do to lose its status as the tiniest planet in our solar system? American astronomer Clyde Tombaugh discovered Pluto in From until , Pluto sat comfortably beyond Neptune as the ninth planet in our solar system. In , however, changes were made. The truth is, nothing about Pluto changed, but the definition of a planet did.
Textbooks had to be rewritten. Members of the public were outraged. Our understanding of the solar system itself was forever changed on Aug. Several years later, many still don't quite understand all the fuss, nor why Pluto was knocked from its planetary position. But the solar system's transformation from nine planets to eight was a long time in the making and helps encapsulate one of the greatest strengths of science — the ability to alter seemingly steadfast definitions in light of new evidence.