I'm astounded that the IAU felt the need to spend time and money to reclassify Pluto, when it had been generally called a planet for decades. I understand the need going forward to have clearer definitions of a planet, but rejecting Pluto as a major planet from our solar system is like dejecting your youngest child from the family, and demoting them to "pet" status. Not as important or respected as the others. Hopefully, New Horizons will produce a slew of new scientific information to regain the major planet status for Pluto, despite its size.

Alan, if we call Pluto a planet, what should we do about other dwarf planets? Should Eris also be reclassified as a planet? Eris is bigger than Pluto...

To me it has nothing to do with Pluto being technically a planet. It's like saying your adopted child is not really one of your children because they werent technically born to you. Because of history having made it the ninth planet, it should stay as such. Don't unring that bell. Any future discoveries and objects not already labeled as planets can fall under the technical rules.

I think Pluto should be given it's title of a planet back as well, and Eris should be classified as one too. Also, what possible name will this new moon of Pluto be getting? Has Cerberus been used for anything yet?

There should be a 'grandfather clause' that allows Pluto to retain its standing as a 'real' planet and anything after that cutoff date will be considered a dwarf planet...

Questions, Comments, Criticisms?

(My Very Excellent Mother Just Made Us Nachos)

What happened to Saturn?

To spot an object only 8 to 21 miles wide from this distance is truly amazing. I would say that if a body in our solar system has a certain amount of moons, then it should be labeled a Planet.

Bah, gone and used a good name on an asteroid? I figured it fit the naming scheme well enough.

How about naming the 4th moon Trantor or Asimov?

They could have called the others dwarf planets and grandfathered Pluto.

However, Ceres used to be a planet. Should we grandfather that one as well?

I thought I was making the third reply, come back after a minute or two and I'm the 13th reply.

I just can't wait for New Horizons to make it to Pluto. Hopefully we'll finally get a clear picture of the icy little thing.

I would say that if a body in our solar system has a certain amount of moons, then it should be labeled a Planet.

NJ Tony, does that mean that Mercury and Venus should not be planets?

I think one of the reasons for Pluto not being a planet is the Center of Mass of the Plutonian system in not within Pluto, or at least it's not thought to be.

For me, it's good enough to accept that Pluto is a dwarf planet. It is still a PLANET! A dwarf planet is still a planet. So, what's the problem? Pluto IS a planet. Kids are going to be taught the size of these things, we were all taught that Pluto is small in comparison to the "classical" planets. I see nothing wrong with calling Pluto a dwarf planet. It's still a planet. You wouldn't call a dwarf person not a person. And if you did you'd be an insensitive ****. ;-p

FudgeFactor, I think it's Served Us Nachos. Someone googed above you.

Mob, compared to Jupiter, Earth is a dwarf planet. Earth also runs into meteor showers every year at about the same times. Doesn't sound like it's cleared out its orbit.

Tony, I pictured that as being one of the requirements, not the only. Its my way of rooting for Pluto.

I'm not saying that the definition of Dwarf Planet should be based on relative size, I'm just saying that as a kid we all learned what size each known planet was. That's all I was getting at with my earlier comment.

As for Earth clearing out it's orbit, we run into regular meteor showers every year, yes. But these come from comets if I'm not mistaken. Earth has cleared out it's orbit of the early solar system stuff, the comets that whiz by since then are why we get these meteor showers. So, it's kind of a different case than "clearing out" our orbit. Also, I'd imagine that after enough time we'll clear out these things as well. But there will always be more comets coming along from the outer solar system "depositing" more stuff and that will create more meteor showers.

Mr Vem J Sun laughs in Pluto's general direction

How can a non-planet have moons?

Blasphemy!

/Hubble is gonna get burned at the stake for this!

Mob, I remember Pluto's size changing. I remember when they thought is was roughly half the size of Neptune and Uranus, twice the size of Earth or so, and one other that I cannot remember right now. (I can see, in my memory, the planet chart from elementary school showing it ~half Neptune size.)

Times change, more info gathered, and we have a dwarf planet. But, if we have a dwarf planet, then Earth and Jupiter should be in different classes.

Don't know. I never really learned the planets that way. I could just name them.

Now, the resistor color code, that one I used for remembering the colors: Bad Boys Rape Only Good Girls But Violet Gives Willingly.

Tony, I majored in Computer Science LONG ago and had to learn the resister colors, but I don't remember that being the same saying to remember the order. I can picture the teacher giving us a way to remember, but not the saying. Now I will have to look it up again. Lol

I could really go for some pizza right about now...

My personal favorite mnemonic device is for remembering the order of the strings on my guitar: Every Apple Does Go Bad Eventually.

But I digest.. err.. digress.

I learned that one in college, and was told it was the one the Navy used.

Well, my schooling was back in 19bla bla bla. Had to build AM radios

Did you wear an onion on your belt?

There was no internet. BBS's rocked!

I don't like the idea of grandfathering Pluto in as a planet, merely for historical reasons, while calling other bodies something else, even though they are larger. Science is confusing enough without making illogical classifications merely for the sake of history.

I'm fine with calling Pluto a planet, as long as one can identify one or more distinguishing properties possessed by all planets (such as being large enough to have a spherical shape). I'm fine with Pluto being a planet as long as Eris, Ceres, etc, also get to be planets.

@ Junicon

I think there's an argument in there to repeal DOMA on the same grounds.

Maybe Snowball could be the permanent name of the moon. LOL

snowball 4 it is!

Can we name a dark moon "Shadow", after my deceased cat?

Maybe we could name one "Spot" as well.

Or Sidekick, since Pluto has been demoted to the solar system's sidekick body.

The planethood bit was extremely arbitrary. They discovered Eris out past Pluto -- and it was larger and rounder than Pluto itself. There are probably dozens or hundreds or who knows how many more objects out there in the Oort cloud.

If Pluto was a planet, logically Eris and all those other ice balls would have to be planets too. So rather than deal with a solar system of potentially hundreds of planets, they decided it was better to say none of them were planets.

Then they designed a set of criteria for "planethood" deliberately worded to allow the 8 bodies they wanted to be planets into the club, but not Pluto and Eris.

.

It was this debate which made them officially name the new body Eris, after the goddess of discord. (I still think it should be Xena dammit.)

This is the No Homers club.

...but you already have a Homer in your club!

...no! No HomerS

This very same Alan has done that... But we argue all the time about it--all in good fun!!

What would happen if Pluto realized how much we neglect it? Would it swap orbits with Urectum permanently? What would be the implications?

Badmouth us to the Oort cloud is what would happen! Disastrous!

We've insulted the gatekeeper to our solar system.

Does that make our system Hell?

Perhaps it is.

Ask_of_its_terrible_secret

Would that be an African or European variety?

Are you suggesting that coconuts migrate??

Not at all, but the angular velocity of an orbital period for a dwarf planet....

Tim?

He's got huge, sharp... er... He can leap about... Look at the bones!

Well, it's pretty obvious.

Really, do dwarfs have periods?

I would say female dwarfs do, (though I think we left the Python references -direct quotes and rephrasing for planetary humor- a couple posts ago).

...I think we left the Python references...

Then how about one to Randy Newman?

No, four is correct. By saying 4 moons *including* the new one, you are counting the 3 originally known moons as well as the new moon.

As a matter of semantics I think it would be more clear if it were worded "3 previously known moons along with the newly discovered satellite.."

my two cents

Alan, what are friends for if not making you nervous and picking on you?

Ya know what, now that I really think about it... I'd just say "Hubble imagery from June 28 and July 3 show the changing positions of Pluto's moons, including a newly discovered satellite temporarily designated P4." Whether they're known or not really doesn't matter does it? Gosh, now I'm getting nervous..

;-p

Alan Boyle, my dear fellow. It isn't a new moon. Made just last week, was it?

To all you folks having a bit of fun here, thanks for the levity. It felt pretty good to have an afternoon chuckle.

The notion that Pluto picked it up just recently is quite frightening. Glad Pluto claimed it, though.

it isn't the Death Star, far as I know. I could be wrong though.

No Four moons is not correct, at least the way the rest of the sentence reads. Read it again. "four known moons with the newly discovered." That adds to 5!

I thought it said "including the newly discovered.." I will read again.

Oh, goodness. It probably is the Death Star. I hadn't thought of that. Were goners for sure now that our NASA program has been gutted. We will just have to get together, pool our resources and make our own Death Star. Since it will be smaller than the actual Death Star, we could call it the "Hurt You A Lot Star."

LOL grump. I can feel a strong force from you. Dark Helmet is coming.

I think the schwartz is strong with grump.

TonyInDallas, it could just be indigestion rather than the schwartz that you are both sensing. I am so sorry.

You know, I have never seen that movie. Shame on me.

Lonestar! We meet at last for the first time, for the last time!

I reject the argument of "having to memorize" a large number of names of planets. If there are 57 planets then we should be taught and tested on the 57 planets. End of story. You can't just gloss over a certain segment of the solar system when you are learning about the solar system. That's just poor educational style.

Memorization is actually not effective or important as a means of learning. We don't ask kids to memorize the names of all the rivers or mountains on Earth, just to know what a river is. We don't say Jupiter can have only four moons because 63 is too many to memorize. Years ago, we knew little more about the planets than their names, so one can understand why kids were taught to memorize their names. Today, that is no longer true, and artificially limiting the number of planets just for convenience has no scientific basis anyway. As for Eris, it turns out Eris is not bigger than Pluto but marginally smaller, as determined in November 2010 when Eris occulted a star. Eris is still a planet, as are Ceres, Haumea, and Makemake (and probably many more spherical objects beyond Neptune) because it is large enough to be in hydrostatic equilibrium, meaning rounded by its own gravity. And if we choose to preclude objects with inclined and elliptical orbits from being planets, we will have to exclude a large number of the exoplanets discovered, most of which are gas giants, as many in multi-planet systems orbit not on the same plane but on multiple planes.

Kids are taught the names of all of the states. Not 57, but close. They are taught names of the major countries and some others depending on the school. It doesn't matter if there are 57 or more to learn. Kids can learn that many. That should never be the reason for limiting anything.

Ever notice that the number of planets and the definitions thereof have changed before, and not in the 21st century?

Get'im Mob!!!LOL We're not re-writng history, We're about re-writing history books to reflect reality...

Well, don't let the Texas school board get hold of the books. Our dumbass board is driving me crazy with the crap they are putting in text books. When they get here (college), our professors have to do a lot of "uneducating" the students before teaching the truth.

TonyInDallas, It's not just Texas, it's all over this country. History is the worst, they have stopped teaching and kids no nothing about this country. I quiz college students all the time and none of them can answer simple historic facts about the US.

It's no big deal really, but using "no" instead of "know" drives me batty, especially when we are talking about education of this nation's children. But that's just me. Do what you will.

My issue with the changes to history books is not just that they are rewritten. There can be valid reasons for that, such as finding out new information. However, we are seeing more and more history being rewritten in order to be politically correct and that bothers me. PC isn't factual. It's based solely on opinions of those who decide if something is politically correct or not. History books should never be changed just to make readers feel better or to avoid horrific information that might bother or offend people. History is important, but only if it's accurate and complete. Yes, things like the holocaust were horrific, but that doesn't mean children shouldn't be taught everything about it. Without paying attention to the true history, you'll just repeat the past.

mob_barley

It's no big deal really, but using "no" instead of "know" drives me batty, especially when we are talking about education of this nation's children. But that's just me. Do what you will.

Yeah! Me to! Perhapse its a problem that wheel look in to before the student's in our country completely lose site of fact and fiction: not to mention proper grammar and elocution. Were are all the educated teachers that can actually provide a lesson with sum redeeming value, Like_such_as_the_Iraq!

eye dowt any 1 no's the reel weigh two right stuff ore said it good..

Agreed, NASA's space telescopes continue to add so much to our body of scientific knowledge. The Webb will be a massive aide in our search to understand the universe more clearly. I hope Congress doesn't screw that up.

So cool! But when are we going to see Hubble images of moon landing sites? A few conspiracy theorists (deniers) out there still need to see them..

@Sandungo:

Here's a link to the LRO website and it has taken pictures of the Apollo sites from orbit:

http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html

Here is a link to the Lunar Reconnaissance Orbiter's images of the Apollo landing sites. http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html

Deniers should realize that Apollo 11's Armstrong and Aldrin placed the first of 5 "corner mirrors" on the Moon's surface. The laser ranging system was used for 40 years. http://www.guardian.co.uk/technology/2009/jun/21/mcdonald-observatory-space-laser-funding

(dang s. mcilnay beat me to it.)

Thanks, guys!.. but I guess NASA doesn't want to waste time pointing Hubble at the moon for any views there(?) Wouldn't the image resolution of landing sites be higher?

Here is a link to the Lunar Reconnaissance Orbiter's images of the Apollo landing sites. http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html

Thanks for the links Mob and McIlnay. I just love it when silly myths are shattered with data.

Thanks, guys!.. but I guess NASA doesn't want to waste time pointing Hubble at the moon for any views there(?) Wouldn't the image resolution of landing sites be higher?

The Hubble isn't big enough to see the Apollo hardware. The Moon is 384,400 km away. At that distance, the smallest things Hubble can distinguish are about 60 meters wide. The biggest piece of left-behind Apollo equipment is only 9 meters across and thus smaller than a single pixel in a Hubble image.

It's a basic limitation of the physics of visible light, which astronomy defines as "resolution" - the smallest amount of detail that may be discerned.

The key limitation in resolution is the size (diameter) of a telescope's main mirror, which in the case of Hubble is 2.4 meters; the bigger the mirror, the greater the resolution. (Also important is the "quality" of the optics; the successor to the title "the largest telescope in the world", the Soviet BTA-6, suffered from really horrible optics, and is considered a "white elephant" even tho it is much larger than the Hale Telescope at Palomar.)

Hubble's maximum theoretical resolution is 0.048 arc seconds (there are 60 arc minutes in a degree, and 60 arc seconds in an arc minute). Resolution is calculated by 116 divided by aperture in mm. = 116 divided by 2400 = 0.048 arc seconds.

From here on Earth, and also from the viewpoint of Hubble's low-Earth orbit, the diameter of the Moon is a bit more than .5 degrees, which is 31'40" (1900 arc seconds).

Therefore HST can resolve an object on the Moon of (1900 divided by 0.048 ) = 1/39,583 of the Moon's diameter

Actual diameter of Moon = 3476 km

Therefore resolvable object size = 3476 km divided by 39,583 = 87 meters

As the Apollo landers are only around 9 meters across it is not possible for the Hubble to resolve them; they are below the lowest possible resolution limit of that size mirror at this distance. At the distance of the Moon, the smallest object that Hubble could resolve would be 86 meters (about 280 feet) across; about one order of magnitude too big to see Apollo. Even then, the hardware would only be seen in a single pixel.

The current largest ground based visible light telescope is the 10 meter Keck, far bigger than the HST and therefore has a far better resolution of 0.012. But this is a theoretical limit that cannot be achieved through an atmosphere, so the HST, being in the vacuum of space, is still number one.

Here is a link...

Thank you both for linking, I enjoyed the view.

WOW. Michael, you really know how to make me feel dumb. I appreciate it though. It's good to know that there are people out there who really know their stuff. Thanks for the detailed explanation!

Just for fun, do you know the difference between the resolution of the LRO and the satellites that provide google earth with enough resolution to see my car?

Mob and McIlnay, those images look like "cosmic ray glitches". Those couldn't possibly be images of our landers.

Mob, the picture that Google Earth has of your car was taken by an airplane; aerial photography.

(I was going to answer with something about "that depends on what kind of car you have" but I couldn't make it funny....)

As for the Hubble resolution info, knowing how well a particular scope can resolve astronomical objects is a rather large part of my work.

Hmm. Well, now I really feel silly. Aerial photography you say? I never would've guessed.

.. You know what kind of car I have, it's the brown dwarf that just won't turn over...

OOPS! A reversed digit in my above post; the first paragraph should read:

The Hubble isn't big enough to see the Apollo hardware. The Moon is 384,400 km away. At that distance, the smallest things Hubble can distinguish are about 90 meters wide [the above mistake - I wrote 60, rather than 90]. The biggest piece of left-behind Apollo equipment is only 9 meters across and thus smaller than a single pixel in a Hubble image.

@ Michael (Astronomy.FM)

I totally spotted it, but didn't want to take you out of your groove

^_^ j/k

Seriously, you are too kind - really!

Can't beat that logic. I'm with you Shawn.

Yep that's my take on it too! And what are the IAU gonna do about all those giant planets out there, orbiting absolutely nothing. The moment science comes along and tries to pigeon hole something... the pigeon up and flies away! Pluto is historically a planet and so is Ceres for that matter. And I defy any IAU bigwig to contradict an historical FACT!

"sub-brown dwarfs"? Don't make me laugh... Methinks the IAU are hooked on HERMIA. "Little again! nothing but low and little!" Midsummer Night's Dream

If that "12 planet"s orbit crossed Earth's orbit then wouldn't that mean that neither planet has cleared out their respective orbits and thusly neither planet is a planet??

They say 95% of the people on this planet supposedly believe in some kind of God or religion of some sort.. So, I don't know if I'd put God down with a goose egg just yet... just sayin'

Mars has localized magnetic fields and a thin atmosphere.

How do you get "atmosphere = magnetic field"?

Isn't an atmosphere more about the existence of gas(es) and an amount of gravity with a magnetic field only aiding in the atmosphere not being stripped away by solar wind?

That is correct.

I think the point of my slightly tongue-in-cheek (did anyone notice?) comment was lost in the world of factoidal debate. Sorry about that. That point being: Planetude, if you will, is in the perception of the beholder. Like Shawn Connolly posted: "It's a Planet if I say it's a Planet."

For example, I don't think of the gas giants as planets in the same sense as ours (or Mars) because of their physical & compositional characteristics (let the factoidal slapdowns begin). Yet, "officially", they are planets no matter what I think, and they're not the same in my mind no matter what "they" think.

How much we are psychologically vested in Pluto's "official" designation depends on us. It is what it is, no matter what we "call" it. In any case, though there are truly much more important things happening in the world than this discussion, Pluto and the capabilities of the Hubble are totally interesting.

No, that is not what that means. The clearing out of our orbit has to do with the stuff that started out in our orbit at the time of the formation of the solar system (if I'm not mistaken).

Hey Mob. How are you doing? I think that John was trying to be funny.

I get it, I get it.

Hear, hear.