Is Pluto a Planet?: A Historical Journey through the Solar System

by David A. Weintraub

A Note from the On August 24, 2006, at the 26th General Assembly of the International Astronomical Union (IAU) in Prague, by a majority vote of only the 424 members present, the IAU (an organization of over 10,000 members) passed a resolution defining planet in such a way as to exclude Pluto and established a new class of objects in the solar system to be called "dwarf planets," which was deliberately designed to include Pluto.


With the discovery of Eris (2003 UB313)--an outer solar system object thought to be both slightly larger than Pluto and twice as far from the Sun--astronomers have again been thrown into an age-old debate about what is and what is not a planet. One of many sizeable hunks of rock and ice in the Kuiper Belt, Eris has resisted easy classification and inspired much controversy over the definition of planethood. But, Pluto itself has been subject to controversy since its discovery in 1930, and questions over its status linger. Is it a planet? What exactly is a planet?



Is Pluto a Planet? tells the story of how the meaning of the word "planet" has changed from antiquity to the present day, as new objects in our solar system have been discovered. In lively, thoroughly accessible prose, David Weintraub provides the historical, philosophical, and astronomical background that allows us to decide for ourselves whether Pluto is indeed a planet.


The number of possible planets has ranged widely over the centuries, from five to seventeen. This book makes sense of it all--from the ancient Greeks' observation that some stars wander while others don't; to Copernicus, who made Earth a planet but rejected the Sun and the Moon; to the discoveries of comets, Uranus, Ceres, the asteroid belt, Neptune, Pluto, centaurs, the Kuiper Belt and Eris, and extrasolar planets.


Weaving the history of our thinking about planets and cosmology into a single, remarkable story, Is Pluto a Planet? is for all those who seek a fuller understanding of the science surrounding both Pluto and the provocative recent discoveries in our outer solar system.

Genres: Science, Nonfiction, Astronomy

272 pages, Hardcover

First published October 16, 2006

About the author

Professor of Astronomy, Vanderbilt University

David A. Weintraub is Professor of Astronomy and Director of Undergraduate Studies, Department of Physics & Astronomy, at Vanderbilt University.

Weintraub is also Director of the Program in the Communication of Science and Technology (CSET) and Co-Director of the Scientific Computing Program.

Weintraub is author of several books, including:

-Religions and Extraterrestrial Life: How Will We Deal With It?;

-How Old is the Universe?; and

-Is Pluto a Planet?

Reviews

[Angela Joves · Rating 5 out of 5]

"Is Pluto a Planet" is a fascinating book. It is a book in relation to the topic of Astrophysics too, and it gives valuable information. This book takes the reader from the ancient astronomy to what and how we see this field nowadays. When speaking of Pluto, the denomination of Pluto as a planet is controversial since it is a dilemma to name it or not! This due to the fact that if we do, name Pluto a planet... a variety of other "planetary objects" would have to be considered planets too. For our understanding, "historically" and "culturally" we would go "crazy" if we now went upon life knowing that our Solar System has more than 23 planets! So according to Michael Brown, this should be left to further generations and their delight of the discoveries.
*The Earth / it can be said that its distance from the Sun is 1 AU (astronomical unit) but this actually only occurs when the orbit reaches aphelion and perihelion. Perihelion is the nearest distance from the Sun and aphelion is the furthest.

[Matt Vetter · Rating 3 out of 5]

Is Pluto a planet? Review
In the book is Pluto a planet a historical journey through the solar system by David A. Weintraub, it explains many different kinds of topics on what is a planet, where a planet is located, and is Pluto a planet. A planet is also called a major planet. There are eight planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, or Neptune. Pluto used to be known as a planet, but found out that it was a dwarf planet. A dwarf planet is a planetary mass object that is not a planet or a satellite.
To the ancient Greeks, the sun was a planet but the earth was not. In the It explains what a secondary planet is and that is orbits around a planet. An example to this is a moon because it rotates around the earth and the earth could be called a secondary planet because it rotates around the sun. To be a planet a planet has to have a star and a moon that orbits around and the size of the planet and the force of mass it has. An example is earth like the sun is the star and a moon orbits it.
I really enjoyed this book because it mentioned some stuff I did not know about the planets, Pluto, and aspects of science and the solar system. If I could rate this one through 5 I would rate this book a 3 because it gets boring listening to what scientist think and not make interviews and tell what people think, but overall this book is really good.

[Jon · Rating 4 out of 5]

It's a history of how planets were looked for and found, and ends with the Pluto "debate". IMHO and that of the author, there's absolutely no ambiguity here. The answer is "Yes". An object is a planet if it orbits the Sun, is big enough to be round, and is small enough so as not to be on fire itself. This metric admits a zoo of other planets into the Solar System, including asteroids, Kuiper Belt Objects, Trans-Neptunian Objects, etc: Ceres, Pallas, Vesta, Hygeia, Cybele, and others. Let 'em in, we both say. We have 20+ planets in the Solar System, and that's a fact. Wake up, it's the 21st Century. New ideas happen.

[STEPHEN PLETKO!! · Rating 5 out of 5]

OH PLUTO! PLUTO! WHAT ARE YOU?

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QUESTION: What is the ultimate goal of this book?
ANSWER: Our solar system historically has nine planets. They are, as you proceed outward from the sun, as follows:(1)Mercury (2) Venus (3) Earth (4) Mars (5) Jupiter (6) Saturn (7) Uranus (8) Neptune (9) PLUTO

The goal of this book concerns the last planet on this list, PLUTO. Is it indeed a planet or is it...something else?

XXXXX

This is the question (in italics) that is answered in this informative, well-written book by David Weintraub, a professor of astronomy at Vanderbilt University (in Nashville Tennessee).

To answer the question, "Is Pluto a planet?," it only makes sense that you have to answer a more basic question: "What is a planet?" This is actually the question at the heart of this book. Despite its simplicity, this question is not easy to answer.

This book reveals how the meaning of the word "planet" has changed from ancient times to the present day. Weintraub provides the historical, philosophical, and astronomical background that allows the reader to decide whether Pluto deserves to be called a planet.

A hallmark of this book is how it weaves the historical with the scientific into a single, intriguing story.

It should be noted that this book was written just before that International Astronomical Union (IAU) decision regarding Pluto. Weintraub, who anticipated this decision, says:

"Making such a decision should not be an arbitrary activity. 'Is Pluto a planet?' is a scientific question , not a matter of public opinion or a decision to be made by NASA or a panel of distinguished astronomers [which the IAU is]. Science moves forward at a pace dictated by progress in understanding, not by fiat or a majority vote of a committee."

The above statement by Weintraub should alert the potential reader to the high standard of excellence that this book aspires too, a book grounded in science and not opinion or majority vote.

Finally, there are pictures, graphs, portraits, etc. found throughout this book. These help in both understanding and adds another dimension to this book.

In conclusion, this is a book for those people seeking a fuller understanding of the history of our solar system, the science surrounding Pluto, and the tantalizing, provocative recent discoveries in our outer solar system!!

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(2007; preface; 14 chapters; postscript; main narrative 230 pages; appendix; notes; index)

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[Kaleigh · Rating 4 out of 5]

I really liked this book. As someone who teaches science to children, it is inevitable (I feel) that the Question about Pluto comes up every couple of months (or weeks, days, etc. depending on what I'm teaching at the time). It always fascinates me how passionate people will get about Pluto's planetary status, especially kids who weren't even born pre-Pluto's "demotion". I picked up this book wanting a little more information for myself, for the records of friends wondering: I very much on the side of "it's really cool to see how science changes and with it, our understanding of how to classify things". That didn't really change after finishing this book, but I did find myself a little more open to the idea that the very impossible Pluto could one day be redefined as a planet, or something else.

My favorite parts about this book aren't actually the ones to do with Pluto, and instead is the way half the book is focused on defining "what is a planet?" Spoiler: that's something that's very hard to do.

I very much enjoyed the parts of this book that went into this history of each planet's, asteroid's, star's, etc status changed, or didn't change throughout history. Pluto's status as a planet or not is much more complicated than a simple yes or no answer and I'm all about that kind of thing.

[Joseph · Rating 4 out of 5]

Interesting material, though it got a little technical at times slowing things down. Still, it taught me plenty about the outer solar system I didn’t know.

[Alan Lewis · Rating 5 out of 5]

Pluto was recently demoted from its previous status as a planet to a Plutino following the recent discoveries of numerous Kuiper Belt Objects (KPO) and Scattered Disc Objects (SDO). While the debate continues and may be reopened to further discussion, David Weintraub, a Professor of Astronomy at Vanderbilt University, has written a fairly short and easy to read history of discovery of the objects in our solar system. That history includes the various ways in which science has classified those objects.


What were considered planets has varied through history. Weintraub continues the survey by discussing various means in which to define what a planet is or should be. In the process he takes a look at other bodies that fall on the edges of definition. These include brown dwarfs, pulsar planets, orphaned planets, and free roving planets that seemed to have formed not in stellar discs but out of material insufficient to create enough mass to ignite and form interior nuclear reaction to burn as a star. None of the definitions Weintraub proposes are satisfactory to solving the question, reasons Weintraub. As a science nerd they do not satisfy me either.


Weintraub concludes that Pluto should be reclassified once again a planet as well as reclassifying other objects as planets as well, including recently discovered 2003 UB213, 2002 AW197, 2002 TC302, 2003 EL61, 2005 FY9, Sedna, Orcus, Quanoar, Ixion, Varuna, Cybele, Hygeia, Vesta, Palla, and Ceres. Granted, he concludes, that they are also parts of object types such as Ceres would be a planet and also a large member of the asteroid belt, Quanoar, Sedna are planets and Kuiper Belt Objects. Pluto is a planet and the premier Plutino.


If you want to know why he concludes such, you have to read the book. I happily agree that the solar system contains more than the currently recognized 8 planets. Good book.

[Julie · Rating 4 out of 5]

This book marks the start of my science-kick reading. It's a great overview of human knowledge of our solar system from the earliest times to the modern day (at the time of publication). When the debate began over whether Pluto was truly the ninth planet or instead simply the largest Kuiper Belt Object (KBO), David Weintraub wrote this book to lay all the facts (as we know them) out there so people could decide for themselves (which I think is pretty cool). Weintraub himself concludes at the end that Pluto should be considered a planet, but that by any definition that includes Pluto, other large asteroids such as Ceres and Quaoar, etc. should be planets as well. He includes commentary at the end from many prominent astronomers, who seem pretty split down the middle on the whole thing.

The writing is very accessible for non-scientists like myself, and includes a bit of math but it is presented in understandable ways. I think this is a great book for anyone interested not just in the debate over Pluto, but of how humans have looked at the solar system throughout recorded time.

[Lance · Rating 4 out of 5]

Weintraub follows sound historical precident for the definition of a planet in trying to determine Pluto's status and answer the question "Is Pluto a planet?". The arguments turn scientific as we go along and Weintraub points out where things go strange with the discovery of Ceres and Pluto. The book is well written and a more resonable fleshing out of the title's namesake. It is a wonder, since this was written before the IAU's Battle of Prague, that they did not take some of his points and questions to come up with a better definition than they did. The book seems like it is a written version of a lecture or class that he has given, but is clearly organized and understandable.

[Stephen · Rating 5 out of 5]

First off, WOO! I finally finished a grown-up book! This was a wonderful history of planetary astronomy. It explains how our understanding of the solar system has grown and changed since the ancient astronomer first observed the "wanderers" in the night sky. At the end I am convinced that Pluto should still be considered a planet, as should about twelve others currently designated as "Kuiper Belt Objects" or "Trans-Neptunian Objects." And if he doesn't agree, Neil DeGrasse Tyson can bite my shiny metal ass.

[Sєlin]

very well done. impartiality on the subject is a good thing..he explains all avenues of discussion.