Why is Pluto not a Planet?

For the final part of the planet-related posts inspired by Mike Brown's book, here is his own explanation of the rationality of an eight planet solar system:

Many astronomers, tired of the endless debates before and after the demotion of Pluto, will tell you that, in the end, none of this matters. Whether Pluto is a planet or not is simply a question of semantics. Definitions like this are unimportant, they will say. I, however, will tell you the opposite. The debate about whether or not Pluto is a planet is critical to our understand of the solar system. It is not semantics. It is fundamental classification. 

Classification is one of the first processes in understanding something scientifically. Whenever scientists are confronted with a new set of phenomena, they will inevitably, even subconsciously, begin the classify. As more and more things are discovered, the classifications will then be modified or revised or even discarded to better fit what is being observed and what they are trying to understand. Classification is the way that we take the infinite variability of the natural world and break it down into smaller chunks that we can ultimately understand. 

So how should we classify the solar system? It's hard because we are sitting in the middle of it and have known planets our whole lives. But let's try to do it from the perspective of someone who has never seen a planet before. Imagine that you are an alien who has lived your whole life on a spaceship traveling from a distance star to the sun. You don't know that planets exist. You don't even have a word for planets in your language. All you know is your spaceship and the stars you can see surrounding you. The sun - which originally looked like any other star - now gets brighter and brighter as your destination nears.  

As you start to stare at and wonder about the sun, you suddenly notice that - wait! - the sun is not alone! You see that there is something tiny right next to it. You're excited beyond alien words. As your spaceship gets closer and you look even more carefully, you suddenly realize that there are two tiny things next to the sun. No, three. No, four! 

You have just found the things we call Jupiter, Saturn, Uranus, and Neptune: the giant planets. From your perspective, still quite far from the solar system, they look tiny and so close to the sun as to barely be distinguishable. You don't have a word to describe them, so you make one up in your alien language: Itsgan. 

You keep looking for a fifth Itsgan out beyond that fourth one you found, because it seems logical that there should be more, but even as your spaceship gets closer and closer to the system, you don't see anything out there. Trust me, I understand your disappointment. 

Finally, as you get close and the four Itgsan get brighter and appear more distinguishable from the sun, you realize you were looking in the wrong place all along. there are other things next to the sun, but they are inside the first Itgsan, not outside. There are four of them, but they're much smaller than the first four you found. So you come up with a new word. You call them Itrraestles. You don't know it, but you've just found Mercury, Venus, Earth, and Mars. 

For a very long time, as you keep getting closer, there is nothing new. Finally, when you're almost on top of the solar system, you realize that between the small Itrraestles and the large Itgsan there is a band of millions and millions of tiny things going around the sun. And looking even more carefully, you see that outside the large Itgsan there is another band with even more. You can them something but I can't pronounce, but I call them the asteroid belt and the Kiuper belt. 

Nowhere in that alien brain of yours would it be likely to occur to you to take one or two or even a few hundred of the things sitting in the Kuiper belt or in the asteroid belt and put them in the same category as the big Irrarestles. Instead, you would quite rationally declare that the solar system was best classified by four major categories. And you would, I think, be correct.

The only thing wrong with our current classification of the solar system as a collection of eight planets and then a swarm of asteroids and a swarm of Kiuper belt objects is that it ignores the fundamental distinction between the [4] terrestrial planets and the [4] giant planets. So even though the aliens call them Itgsan and Irrarestles, we'll lump them together and just call them all Tsapeln. 

If you didn't notice that the alien jargon was just the scrambled forms of "giants, terrestrials, planets" don't worry because I didn't either at first - even AFTER he discussed this technique used by other astronomers for other nomenclature. As you can deduce, Pluto is just one of the many members of the Kiuper belt. When it was discovered in 1930, there was little controversy over its planetary status. Later evidence of a moon even reinforced the claim! But after Brown's discoveries, Pluto was finally put in its place. Before I conclude, I want to mention two important aspects of the book I haven't touched on: one fundamental and one personal. When Brown discovered an object now called "Haumea," another group in Spain plagiarized it as their own by tracking down its location from an online data center coming from a telescope in Hawaii. It's a shame but plagiarism truly exists everywhere: http://en.wikipedia.org/wiki/Controversy_over_the_discovery_of_Haumea.

Secondly, Brown actually got married and had a child during the course of these events!! He spent quite a bit of time writing hilarious accounts of the "scientific approach" involved in caring for Lilah:

Lilah did little more than sleep and eat and cry, which to me was the most fascinating ting in the entire universe. Why did she cry? When did she sleep? What made her eat one day and little the next? Was she changing with time? I did what any obsessed person would do in such a case: I recorded data, plotted it, and calculated staistical correlations. First I just wrote on scraps of paper and made charts on graph paper, but I very quickly became more sophisticated. I wrote computer software to make a beautifully colored plot showing times when Diane fed Lilah in black; when I fed her in blue (expressed mother's milk, if you must know); Lilah's fussy times, in angry red, her happy times, in green. I calculated patterns in sleeping times, eating times, crying times, length of sleep, and amounts eaten. Then, I did what any obsessed parent would do these days: I put it all on the Web. It's still there, at least until Lilah gets old enough to find it and is sufficiently mortified that she makes me take it down (www.lilahbrown.com).

The website actually drew an international following of people who would remind Brown to update when he missed a few days. Parents to this day email him when they stumble upon the page thanking him for keeping them sane and realizing that their baby was normal with his/her (seemingly) unusual daily habits.

I found this book to be fascinating because of the incredibly long-winded story behind what transpired to be one of the biggest discoveries in the field of planetary astronomy. It inspired me to want to read into other discoveries - not just in astronomy or even the sciences but in subjects that I've ignored to take an interest. As Brown writes himself, I hope from reading these posts you have a further appreciation of not only the actual subject of astronomy but the nerdy looking professors in the Astronomy, Physics, or any science department that seem incapable of having friendly personalities. Their published work may not seem to be interesting but they all have incredible stories of their own. This was Mike Brown's story.

Patellin' you about Planets II

In the end of my last post about Mike Brown, I highlighted the scientific and linguistic discussion over the word "continent." There are actually many similarities between the debate over the definition of "continent" and of "planet." To quote Mike Brown:

When people describe their neighborhoods, the landmarks to specify the points and they don't care about the scientific meaning of the words they're using; they care about recognizable landmarks to specify the points and the boundaries of their lives. The planets are these landmarks. That is what people mean when they say the word planet.

There is little need to provoke an extended debate over the definition of "continent" in the scientific community as the social implications are more applicable than its scientific meaning. Mike Brown does care about the scientific meaning of planet. Maybe his background will highlight this fascination: he was grew up in Huntsville, Alabama, "a thoroughly, dedicated rocket town. The father of everyone [he] knew - [his] included - was some sort of engineer working to build the Apollo rockets to send men to the moon. For a while as a child, I thought that when you grew up you became a rocket engineer if you were a boy and you married a rocket engineer if you were a girl; few other options in the world appeared to exist." Since childhood, he had always been involved with astronomy to a degree. His first passion was the moon. We learn later on his career that the moon becomes his "enemy" in a way because on nights of partial or full moons, the other celestial objects would seem relatively dim to the telescopes. Would you be able to see stars with a giant lamp post in the sky?  But I regress. Why did Mike Brown have the right to title his book "How I Killed Pluto"?

Because he discovered the tenth planet! Planet X, then temporarily called Xena ,was officially classified as Eris - the goddess of strife and discord -  for all that happened surrounding its discovery. At the time (2005), many objects from the Kiuper belt area in the solar system had already been discovered (mostly by his team) at an extraordinary pace.  The Kiuper belt is similar to the asteroid belt between Mars and Jupiter but it's located just past Neptune. The word "planet" had become a subject of controversial debate when the media and the International Astronomical Union (IAU) learned of planet X's discovery. The question at the time wasn't whether X was indeed a planet as many of the astronomical governing boards and ALL the media had declared but what would happen next. Planet X was found the be even larger than Pluto but at a distance of 96.6 AU - three times as far as Pluto! If you look at the image above of Eris (and read how planets and other bodies were discovered in the previous entry) you can picture the meticulous effort that is invested in order to find these distant astronomical objects - and how incredible Pluto's discovery in 1930 must have been. It was apparent, though, that with the increase in technology, other objects of comparable magnitude were bound to be discovered somewhere between or a bit farther. One lead official with the IAU had told Mike Brown that based on the currently lenient requirements, hundreds of objects could soon by classified the same way.

However, sensationalist media had no idea of these implications - they were fascinated by Mike Brown: the only living discover of a planet! A legend not only in astronomy but also in every academic field.  Although Brown was a guest on Good Morning America with Diane Sawyer and had articles in every major newspaper, he knew all long what the right move was. Brown took the higher ground for the sake of the scientific community by putting his discovery in its proper place (classification). Members of the IAU had spent months debated over the definition of a planet throughout the time frame of Brown's discoveries (2002-2005). Brown organized a  live streaming in CA where he narrated the IAU conference being held in Europe (forgot the country) to hundreds of media members, academic leaders, and curious bystanders. After the decision was voted upon that Pluto was not a planet and was to be officially classified as a "dwarf planet" along with two other objects discovered by Brown, he was finally at ease. Those who did not understand the situation were justifiably outraged. Teachers, parents, even children began sending angry emails to Brown asking "Why did you have to kill Pluto? What did Pluto ever do to YOU?" I cannot possibly do justice to the response Brown published in his book so I took the time to type up the three pages in the book. The quote and my comments deserve its own entry so scroll up and read his own explanation.

Patellin' you about Planets

While a lot of my friends are having incredible summers doing everything from volunteering at an orphanage center in Cambodia to interning with major accounting firms in New York City, I'll be spending my vacation time slaving way for a single test: the MCAT. As some of you reading may already know, the MCAT preparation books, courses, and the test itself ($240!) are quite a toll on the bank account. So at the start of my summer break, I ventured down to the local library to see if they had any MCAT books to check out for extra passage practice. Unfortunately, the most relevant study aid the library had for me was "Biology for Dummys."

After spending the next 10 minutes looking for ANY book to make up for the lost cause I grabbed "How I Killed Pluto" by astronomer and Caltech professor Mike Brown. I remember (nonchalantly) reading about Pluto's demise as a planet a few years back, not bothering to understand the actual reasoning behind that (apparently) ground-breaking decision.  Being an indifferent sophomore in high school, my rationale was that Pluto was just too damn far. I chose this book in particular though because I've become a huge fan of astronomy and physics the past few years (more on that in the future). However, the only knowledge I possess is the layman's version not involving any complex mathematics, mostly the conceptual framework. I figured Mike Brown was one of many scientists who had claimed to be the ambassador for the case against Pluto in order to get his 15 minutes of fame. I didn't really care about him individually - I just wanted a more in-depth explanation of poor Pluto.


Fast forward to two days later: I ended up finishing the whole book. I was hooked after the first chapter. Mike Brown is a LEGEND in the field of planetary astronomy as well as a fantastic writer. He pokes fun at any previously held stereotype I had about astronomy and physics professors by showing off an amiable personality through his writing. What amazed me the most was his incredibly insight into the inner workings of science. I want to spend some time explaining the facts and theories that were the most memorable. As many of you may understand, I only seem to recall the overall message (or the fate of the major characters if it's fiction) of meaningful books I've read. A reason I created this blog was to record the more insightful passages in my reading. So let's start by me Patelling you a bit about Planets:

The original ancient Greek meaning of the word "planet" was "wanderer." This nomadic definition fully accounted for the discovery of all the earliest planets. People looked up in the sky and noticed that almost every object remained stationary each night except for a select few: the "planets." Obviously then, the first planets were the most visible ones: Mercury, Venus, Mars, Jupiter, Saturn, the moon (HA) and the sun (HAHA). Planets and astronomy were considerably more interesting to the public and the hierarchy of the sciences in those days. Did you know that all the days of the week were named after them?

Sunday, Mo[o]nday, and Satur[n]day are the most obvious, while Tuesday through Friday are more than a bit obscure. Tiw was an ancient Germanic god of war, as Mars was to the Romans, so Tuesday is actually Mars's day. Wednesday is Woden's day. Woden was the carrier of the dead - a Germanic grim reaper - fulfilling one of Mercury's less well known jobs. Thor was the Norse king of the gods, like Jupiter, and Friday is the day of Venus in the guise of the Norse Frigga, the goddess of married love.

When even MORE objects in the distant sky (asteroids, moons, comets, galaxies) were discovered, systematic classification rules were defined for literally every kind of object in the sky. "Craters on Mercury have to be named for deceased poets; moons of Uranus are names for Shakespearean characters." All this time, my ignorant self just thought that these obscure objects would instead be named after Battlestar Galactica characters.

Now I don't want to bore you with how astronomers used to look for new potential planets (and their moons) but the meticulous approach boils down to just a more technologically savy way of the old-fashioned "wanderer" method. They look through the lenses of giant observatories, analyze all the data with extremely expensive equipment, and then write computer programs to account for any pair of frames in the images where a single dot in one frame has moved (or is a little less dim) in another. That right there was probably an oversimplification of about 50-75 pages of history and (not boring) detail - but that's basically what happens.

What is more interesting though is the linguistic and philosophical debate over classification in any branch science, "When is something a mountain instead of a hill? A river instead of a stream? A lake or a pond? An ocean or a sea? Geologists never attempt to define these things. The words simply mean what people think they mean when they say them." They are defined simply by tradition. Take the term "continent" - Brown literally walked around Caltech looking for answers about a concrete definition and never got a satisfactory reply. Every explanation contradicted itself. Why is Greenland not one while Australia is? "It has its own continental plate." Well continents have been around much longer than the tectonic plate theories of the 70s... With that definition BOTH New Zealand and India should be their own continents.

As I quizzed more and more people, I learned, for example, that many Europeans do not consider Australia to be a continent. Argentinians consider North and South America a single continent. And rational people in many places believe that Europe is considered a separate continent only because, well, that's where the people who defined the continents in the first place all came from. Can it really be that the most important classification scheme for our understanding of landforms has no scientific basis whatsoever?

How all this relates to Pluto and Mike Brown's career in Part II.