Wednesday, 27 January 2016

Planet 9 or Planet 10? At least call it Planet Bob for now.

@micquai had some fun.
Today's TASE Day is brought to you by the ever-interesting kerfuffles that happen within Astronomy circles. This is far more fascinating, optimistic and potentially science-furthering that the last debacle involving sexual harassment.

New Planet?

Today's hot-and-bothered fun is revolving (pun intended) around the unofficial nomenclature of a possible new planet in our solar system.

We're not talking yet another dwarf planet, but a large, solid(-ish) no-IAU-doubts-about-it Planet (with a capital P).

Astronomer Mike Brown (fondly known as @PlutoKiller, and for good reason), has been calling it Planet Nine.  This is because the International Astronomical Union (IAU), since 2006, has reclassified the rocks revolving about our Sun into different categories.  The most famous category is Planets, of which there are officially eight.

So, going by the official IAU definition, if this mystery planet is as massive as they believe it is, it would make official sense to call it Planet 9.  He's blogging about it at Find Planet Nine.

But a lot of people are freaking out about its name.  Isn't Pluto supposed to be the ninth planet?

Not any more.

Before the official IAU re-definition of what a "Planet" was, we (the general populations of humans currently living on Earth) identified with nine: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.

So, most everyone who was born in the 20th Century (and hadn't studied the history of astronomy), have always believed there to be nine planets, no more, no less.

Then we started discovering more. And more. Eris, Makemake, Haumea, Sedna, Quaoar... the list goes on.  Astronomers everywhere started finding more and more of these little Pluto-sized planets roaming about. Not wanting to confuse kids who had learned that their very educated mothers can now serve us more than nine pancakes, the IAU did a reclassification; Pluto and several of his sisters are now Dwarf Planets.

A lot of people channeled their newly-discovered inner Plutophile and got their panties in a twist. Understandable. Most humans are discomfited with change.

Me, I'm okay with their being currently eight major planets and a handful of named dwarf planets. I can't get up in arms about Pluto, because long before there was a reason to get up in arms over Pluto, I was up in arms over Ceres.

Anyone who says in my presence, "Reinstate Pluto as a planet!" I say to them, "What are your thoughts on Ceres?" because Ceres was once defined as a planet, and enjoyed that status for a good fifty-plus years.  As a junior astronomer, I thought it dreadfully unfair that it got demoted.

However, it made sense. As more and more bodies were discovered in the orbit of Ceres, we learned that this little world whom the Dawn spacecraft is currently keeping company, was not alone. Vesta was discovered and more rocks. Lots of rocks. Enough that we called them asteroids. Thus, Ceres got demoted. Still, I'm happy to call Ceres a planet (dwarf or otherwise).  It's not her fault if she was the victim of the Grand Tack model.

So yeah. This whole brou-ha-ha over Pluto's demotion? Seen it before with Ceres. Only this time, the flames of controversy have been fanned by the hot wind known as social media.

But that's not going to stop people wanting Mike and everyone else to call this newly-hypothesised planet Planet 10.  Doesn't help that it's also being called Planet X (X meaning "mystery" or "unknown", not the Roman numeral ten).

I propose we could call it Sol o, after the current exoplanet naming convention.  (Okay, so what if that convention is for naming exoplanets and not the planets belonging to our solar system?) However, since Planet X is too confusing and Planet Nine might not be socially acceptable, I don't mind calling Planet Bob Sol o because...

Earth = Sol b
Mercury,Venus,Mars,Jupiter,Saturn = Sol c,d,e,f,g
Uranus = Sol h
Ceres = Sol i
Neptune = Sol j
Pluto = Sol k
Haumea = Sol l
Eris = Sol m
Makemake = Sol n
Planet Bob = Sol o

Note, I didn't include Sedna and a few named others in this list, as they haven't been officially recognised as Dwarf Planets yet by the IAU.  So if we happen to locate and confirm Planet Bob before more Dwarf Planets get officially accepted, Sol o is a perfectly good name until we can raid our Roman mythology for an official moniker.

Waitaminnit. You mean we haven't discovered Planet Bob yet?

Depends on what you mean by "discover". Funny thing about astronomy. We look up into the sky, we see stuff, then it takes us a very long time to figure out what it means. Sometimes we're right; sometimes we discover something new and unexpected.

Mike believes Planet Bob is out there because gravity. Gravity is a very good way for astronomers to figure out the existence of stuff we can't see. (Like dark matter, etc.)  It is how we postulated and later discovered Neptune (Uranus' orbit had a few gravitational discrepancies that later led to Neptune's discovery). There is also a very good chance that we might have taken a picture of Planet Bob during our many astronomical surveys, but haven't had a chance to get around to analysing the data yet, or analysing more of Mike's pool of data (re: Planet Bob) and married the two up.

This taking pictures of stuff in the sky and not knowing what it is, is pretty much how we roll in astronomy.

We'll do astronomical surveys (ie taking detailed pictures of stuff in the sky), let the astrophysicists propose the existence of something somewhere, then we go back and look at pictures to see if anything in those pictures matches up.  This happens so often we have a name for it: precovery. Lots of stuff has been precovered

One slight problem with this precovery option. There's a possibility that Planet Bob might be in the particular part of its orbit that places it against the background of the Milky Way Galaxy. There's an awful lot of bright stuff there, and spotting an apparently small, Magnitude 20-something planet might be incredibly difficult.

Still, we humans love a challenge. But we also like letting our imaginations run away with us.

Maybe for now we should call Mike's Planet Nine and Plutophiles Planet Ten --- Planet Bob.

Her Grace would much rather get upset over the proposed naming of Epsilon Eridani b to AEgir, especially as much of the human race knows it (subconsciously) as the planet Vulcan. However, if you're completely NOT into Star Trek, it is also the star system where Babylon 5 is located.

Was chatting to a mate of mine about this subject. Kept talking about Sol o.  So my mate says, "Why don't you call it Planet Han instead?"  Groan.

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