Rise of the Dwarf Planets

This post is a follow up to last week’s “Rise of the Planets”. I just wanted to point you to the table of Dwarf Planets listed on this page so you can marvel at how many more planets there could possibly be within our own star system. Of course, Mike Brown (the pluto killer) doesn’t consider dwarf planets as planets and that’s fine with me. But I think that dwarf planets are bona fide planets. And I am simply posting this to bring into attention the growing evidence that smaller planets are more numerous than bigger ones. And i think that this pattern can be discerned even within our own star system.

Look at how many more possible dwarf planets there are! It would be fun if we maintained a scoreboard between "local" planets and exoplanets. Indeed it might be fun to pit local planethunters versus exoplanet hunters in a friendly competition to see which one discovers the most planets!

Links:
How many dwarf planets are there in the solar system?

Rise of the Planets

Three new Dwarf Planets were recently discovered in the outer reaches of our solar system. News like this is simply music to my ears. It doubles the fun of an equally growing list of exoplanets! I love Planets and there's simply no other joy than seeing the list of Planets within our solar system grow more and more. In the coming years Dwarf Planets will become the largest contributor to our local tally of Planets.

But wait! Did I just say Planets? Yes, I consider Dwarf Planets as bona fide Planets. I do not subscribe to the third criterion of the "official" definition that planets must clear their orbit of other objects. I think I'd rather stop at the Hydrostatic Equilibrium part.

I can already hear the shouts and sneer from the interwebz, “You’re wrong! You're so damn wrong!” Yes, I know. I’ve already explored that avenue. And specially after watching this talk, You Have No Idea How Wrong You Are, I can argue no further.

I’m wrong. I’m biased. And I confess, I simply want more Planets in our own star system. Guilty as charged. The more the merrier, I shout it all over the rooftops.

Or maybe I just prefer the Linnaean taxonomy wherein objects are classified into large groups which may then be subdivided further--such that if it was applied to Astronomical objects, Dwarf Planets would still fall into the "Phylum" Planet. But then again, No. Astronomy is not Biology. So that’s that. I'm wrong and leave it all behind for now to move on to the cool part of why I even began writing this post.

What do Dwarf Planets have to do with Exoplanets? Well, there’s growing evidence that smaller planets are more common in the galaxy. At the moment, the findings range only between Jupiter-sized planets and rocky Earth-sized planets (because we haven't even found exoplanets the size of Earth yet!) There are more smaller planets than there are gas giants. As Geoff Marcy says, "There are some Jupiters, there are some Saturns. But there are far more of the smaller and smaller planets going down to about two Earth diameters."

I'm inclined to think that this pattern extends to sub-earth-sized planets all the way down to the smallest gravitationally rounded objects orbiting stars. When you think about it, it makes sense. There are more sand grains than pebbles, more pebbles than boulders. So as the years go by, this fact will be confirmed even within our local star system. More Dwarf Planets will be found, heralding the inevitable rise of the Planets.

Links:
You Have No Idea How Wrong You Are
List of Gravitationally Rounded Objects
3 Dwarf Planets Discovered
Smaller Planets More Common

Exoplanets are not Planets

How long will exoplanets keep on destroying our predefined notions? Just a few days short of smashing our theories of planetary formation into smithereens, now we have two exoplanets sharing one orbit.

According to the International Astronomical Union (IAU) a planet should clear its orbit of other objects. This condition was a source of heated debate among astronomers that rages on to this very day. It was this alienating third criterion that dethroned Pluto and other dwarf planets from planetary status.

So when I heard that KOI-730's exoplanets were sharing orbits, my first reaction was, “Hey wait a minute...if we try to apply the ‘official’ definition of 'planet' to these exoplanets, they would not be planets at all!”

This is just one instance, but i'm sure there are many derivatives of the case of KOI-730's co-orbiting exoplanets that "share" orbits with other objects. Think of intersecting resonant orbital paths, or locked LaGrangian exoplanet orbits, or exoplanets still in the process of clearing out debris in their path. (It would take millions of years for young planets to clear their orbital zones, mind you.)

I’ve always thought that exoplanets are planets. But today, I'm rethinking that. Yes, exoplanets continue to surprise us, and it's for that reason that I once concluded, Exoplanet is the new 'Planet' by virtue of the awe and wonder that they instill upon us. But now, I’ve come to another realization: Exoplanets are not Planets, and that is liberating. It frees the mind from a limited way of thinking, because the mindset needed for understanding exoplanets is different. Exoplanet discoveries forces you to unlearn, and it frees your mind from the confines of your own star system. Exoplanets require a novel way of thinking. And that is why I love exoplanets so much. They make us think in new ways. Exoplanets make us think outside the sphere! And all that is possible because of Science.

It frustrates me when some astronomers deny dwarf planets of being planets, and yet speak of exoplanets as planets in a carefree way. I want to avoid being annoyed by such inconsistent mindset. So I am letting go of the debate about planets. (Of course, I still consider dwarf planets as legit planets) I will simply let planets be planets, and exoplanets be exoplanets. Just that. I will not try to make exoplanets fit in as planets. I will not even attempt to redefine what a planet is, or grumble about its flawed definition. In fact, I'd rather we keep the current planet definition the way it is now. Let it be a reminder, a tainted bygone--an old ugly chapter in the history of Astronomy.

Perhaps someday, a new definition of the planet will emerge, one that is more universal, that will encompass exoplanets as well. But for now, we are experiencing a temporary chaos brought about by the "growing pains" in our effort to understand the universe.

But until then, with the narrow-minded planet definition we have arrogantly locked ourselves into, who can say with certainty that exoplanets are planets?

This is a new era of planetary thinking. Humanity’s concept of the Planet is of the past, but Exoplanets are of the future.

Links:
NewScientist: Two exoplanets found, sharing one orbit
Life, Unbounded: Make Me a Planet
Theories of Planetary Formation, Busted
Exoplanet is the new 'Planet'

Exoplanet is the new Planet

I try to stay away from the debate about Pluto. My issue is not about Pluto. It's about the Planet. One can mock Pluto a thousand times over, and the best (or worst) it could do is annoy people. Sometimes it does get to me, so i have to remind myself that I am more concerned about the concept of the planet, and the idea it represents, and the ideal it imparts to the human psyche.

Let me begin by saying that I think I am falling in love with planets. I don’t know how, but during the course of following the saga of exoplanets it must have been inevitable (after all, the ‘exoplanet’ bears the name of ‘planet’).

With new discoveries that pour in almost daily about planets in other star systems, Exoplanets are a constant source of amazement. They continue to remind me that I can never know enough, that this fascinating universe is an endless source of wonder.

But...something keeps getting in the way. Something mind-numbing creeps in when I read something about what a ‘planet’ is defined to be. It has bothered me so much that I had to use “worlds” as an alternative keyword to hook me back in wonder about these spherical objects in space.

Why? What happened with the term “planet”? What happened with the magical and mythical concept that the Greeks once started with, saying that these mysterious points of light are ‘wanderers’?

The problem began when mankind started to *define* the Planet. We relentlessly squished the concept of a planet with words so that it could fit within our tiny skulls.

I looked into the two sides of the debate, learning as much as I can to understand, but the mandated definition of the Planet really does not appeal to me. In the spirit of freethinking, I humbly decline to subscribe in the 'official' definition of the planet.

Why? What have humans done to the concept of the planet?

There is nothing inherently wrong with classifying things, and certainly nothing wrong with identifying the boundaries in order to characterize objects, but I think we had the wrong attitude when we made up the criteria for planets.

And that is the sad thing about it. Instead of trying to widen the concept of the Planet, we tried to limit it. The kind of thinking that is promoted by the current definition of the planet is a divisive mode of mentality. You see, in our world, much strife is borne out of a discriminating mindset--a way of thinking that focuses on the differences and not on the similarites.

"The major problems in the world are the result of the difference between how nature works and the way people think." ~Gregory Bateson

Today, dwarf planets are not considered planets at all, despite calling them 'dwarf planets'. Is it a matter of linguistic fallacy that makes it all nonsensical? (Dwarf galaxies are galaxies, and dwarf stars are stars, but dwarf planets are not planets?)

Or is it just the mode of thinking? Why deny dwarf planets of being planets? Such judgement mirrors a way of thinking that is alienating and divisive.

It is certainly valid if you consider dwarf planets as a subset or variation of the wide scope of planets. This alternative method of classification exemplifies a way of thinking that respects differences and yet aims to see things as One.

You can choose a mindset that seeks to see all kinds of planets in a wholistic fashion, and delight in their diversity. Or you could choose a discriminating mentality, segregating a class of planet-worlds that don’t fit in your limited notion based on one star system alone--yours.

The Pluto debate is a clash of mentalities. And it has marred the concept of the planet. I hope that the next generation never inherits the discriminating mentality that is present in that conflict.

I rest my case in the lessons that exoplanets are teaching us. They continue to challenge our pre-defined notions of what a planet truly is. They continue to be a source of wonder, in the same way that the Ancient Greeks felt about their ‘wanderers’. In our modern era, only the Exoplanet can conjure that feeling of mystery and discovery ascribed to such mysterious objects.

For me, Exoplanet is the new Planet.

I wish we never end up defining the Exoplanet in the same way we did for the Planet, for I wish to keep the concept of the Exoplanet with awesomeness and wonder.

Double Planet and the Planetary Archetype

Sometimes it takes a new set of eyes to see things in a whole new way. Throughout our lives we see our planet from a single vantage point--from its surface.

Then something deep within us is awakened when we see our own little home from a different viewpoint.

Take a look at the latest snapshot of our home planet--the  loopback address--from another set of eyes called MESSENGER, gazing back at the Earth from within the orbit of Venus. Looking like a double star, some people simply called those two bright lights as a "Double Planet", seemingly unwary of the ongoing debate about what a planet really means.

For the few, the words just naturally comes out upon seeing Earth and it's moon in a different light. When viewed from way out there, the scene tells the mind that the smaller piece of sphere is a member of the archetypal “Planet”.

But most people delve into the technical side of thinking, getting into the nitty-gritty details of defining "planet" based on one humdrum star system alone--ours.

We’ve recently heard that the moon has been called as a "Satellite Planet". But what makes a "planet" a planet? Do we really need to see things from another viewpoint before we can call other objects as planets?

Perhaps.

My opinion is that many objects in our solar system are planets. Yes, I mean those round dwarf planets that many folks refuse to consider planets, despite calling them "Dwarf Planets".

Through the years, as I tracked the new discoveries in exoplanets, i've realized that the current definition of a planet--that definition which was voted upon--is rigidly based on our solar system alone.

Indeed, there are many exoplanets that would not be planets at all if we applied our heliocentric definition of “planet” unto them. For example, there are exoplanets with highly elliptical orbits that do not lie within the plane of their system. And then there are those that share the same orbital zone with other planets via resonant orbits, and others with retrograde orbits, and so on, ad inifintum, ad weirdum.

With all the weird new discoveries of other planetary systems that challenge our limited notions of a planet, I am led to conclude that the greatest factor of what a planet is boils down to the simple quality of being round. In scientific terms, its the hydrostatic equilibrium, the balance between gravity and pressure that molds lumps of matter into a spherical shape.

To me, that property of roundedness is the Archetype that makes an astronomical body (that orbits a star) a true planet. Round is simple, round is sublime.

Often, when I look at the moon, I see a planet. And it’s good to see it that way from a different vantage point as well. And when this satellite planet is seen together with the Earth, what we're truly seeing is a double planet.

Links:
MESSENGER: A snapshot of home http://www.planetary.org/blog/article/00002626
A 'Double Planet Seen from Mercury http://news.discovery.com/space/a-double-planet-seen-from-mercury.html

Pluto, Plutoids and Exoplutoids

At first I was saddened when Pluto was demoted from planethood. Then I was amused by the new classification called "plutoids". I love playing with words, but plutoid sounded too funny to me. Why not have Jupiteroid, or even Earthoid? And all the debate that ensued about pluto's demotion just prompted me to call Pluto as the Great Hemorrhoid of Astronomy, because it was painful to "lose" such a planet.
However, we are given a consolation by the fact that Pluto is still a planet in some way, eventhough the IAU denies it being so. Yes, it is actually a dwarf planet, and a first in its class called "plutoids".
So let us examine the heirarchy of these 3 terms: Planet, Dwarf Planet, and Plutoid.
A planet is a round object that orbits the sun. Its large enough for its gravity to clear out the rocks and other debris within its orbital path.
A dwarf planet is also a round object that orbits the sun. But it is too small to have anough gravity to clear out debris in its path. Hence there are other objects sharing its orbital path.
A plutoid in turn, is any dwarf planet that orbits farther out than neptune (a trans-neptunian object or TNO).
Ceres is an example of a dwarf planet. It is round and it orbits the sun in the asteroid belt, along with millions of other smaller objects. Pluto and Makemake are also dwarf planets since they also share their orbital path with other objects , but they are also plutoids, as is Eris. They are plutoids because they orbit farther from the sun than the farthest planet, Neptune.
So currently, some established members of the plutoid class are Pluto, Makemake, Haumea, and Eris. But it could well grow to more than 70 in a few years time as more dwarf planets fall into the class of plutoids.
Unlearning is also part of learning. And this is what progress in Science is all about. Painful and controversial as it may have seemed, the IAU's decision to "demote" pluto was necessary to for a better classification of a bewildering array of celestial objects orbiting our sun. To a certain extent, I support the IAU on their decision (even though it still needs a little tweaking). Most often than not, collective intelligence is smarter than emotions, and I believe it will sway one final tweak to simply put dwarf planets as a subset of the broader term "planet" to settle the debate.
Now what does it hold for Exoplanetology? As it will turn out, the term plutoids would actually make it easier to categorize "extrasolar dwarf planets" that fit in place: Exoplutoids! But it will be decades AFTER planet-hunting capabilities resolve to discovering earth-like planets. Then we may actually discover exoplutoids next.