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Our Moon Could Become a Planet
anthemaniac writes "Earth's moon is drifting away from us more than an inch every year. In a few billion years, if the system survives, the moon would be reclassified as a planet under the new IAU definition. You gotta wonder if the astronomers who dreamed this definition up had thought of that."
That's no moon!
OF COURSE it would. It would no longer orbit the earth, so it would no longer be a moon.
This smacks of an elementary-level understanding, I don't know why it made the front page. If you change the physical properties of a named object, and want to name it something else, who cares?
both the Earth and Moon will have been swallowed up by the Sun when it becomes a red giant...
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
"The sun will turn in a red giant before the moon gets far enough away to be classified as a planet"
extern warranty;
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In a billion years propably the defintion of planet will have a few thousand updates.
The problem will fix itself in time I guess.
No-one knows if the humans will survive that long, maybe there will be no-one to rename it.
...oh well, forget it, it's still a moon.
...at least the tallest ones.
Reminds me of that old joke telling that a quick computation on the evolution of this distance placed the moon 4 meters away from the earth 65 million years ago and thus explained why the dinausors died.
In other words, when the Moon sufficiently escapes the Earth's gravitational pull, it will no longer be our moon.
How.... bizarre. It would be as if we stopped calling babies "babies" simply because they got older or stopped calling lakes "lakes" just because they dried up!
Clear, Dark Skies
Seriously though, the International Astronomical Union better give this a second thought. I may be woefully ignornant on the subjecct but I really don't see why sticking with the current definition is a problem. I wish the article gave more information as to why they're 'fixing' that which doesn't appear broken.
I know a lot of the other comments about this are just saying that our system probably won't be around or that of course it won't be a moon because it's not in orbit, but what I think is more interesting is about the definition of a planet which they seem intent on creating...
Pluto may oir may not be a planet, but who cares? Don't change the definition because it doesn't change anything and it alters what we have traditionally though of it as and causes confusion with no real benifit. As to the three new planets which might come about because of this I think we should treat them with scepticism, I'm not completely against change if there will be an imporvement to understanding but I feel these things are not really in the spirit of being "planets" (I know that sounds crazy but you probably know what I mean...)
*''I can't believe it's not a hyperlink.''
In a few billion years, if the system survives,
If we manage to figure out a way to move Earth away from the sun before it goes red giant, it will most likely involve leaving any unnecessary baggage (like orbiting balls of rock) behind.
I really don't think humans will last another thousand years (with the way we're poluting the environment and declaring war on each other plus the rising threat of nuclear weapons) let alone another few billion years. And provided we do last that long, I'm sure the standards for classifying planets will have changed hundreds of more times by then.
That's no moon.
But the real question is .. can we live there?
I would want to move from earth after a few billion years
Sent from my desktop computer
"I for one welcome our new IAU overlords"
- anonymous Moonling
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
So is this established fact now? I thought the that was far from proven, and even a quite debated theory.
But maybe the impact hypothesis has gained traction in the science community since I heard of this?
Beware: In C++, your friends can see your privates!
only about 10 - 15 million years, IIRC. That seams to be the length of time that a species dies off (Stephen Jay Gould).
Please stop giving +1 Insightfuls to people who either a) haven't read the article or b) haven't undestood it. The moon could be reclassified as a planet EVEN IF IT STILL ORBITS THE EARTH. It depends on whether the center of gravity of the pair is inside the earth or not.
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If the center of gravity of the pair is outside the Earth, then it's not orbiting the Earth, any more than the Earth is orbiting it.
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We need to have scientifically accurate definitions, we can't just bend to history. Otherwise most of the world would still be using the unwieldy imperial system instead of the easy and elegant SI system of units.
The problem is they're saying if a "moon" is orbiting a barycenter that's not inside another planet, then it's not orbiting that planet and becomes a planet itself. For this reason, they argue Charon is a planet, rather than a moon.
The problem is that barycenter of Jupiter's orbit around the Sun is also outside the Sun. Therefore, by the same logic, Jupiter wouldn't be a planet.
Bruce
I think that if they move to the new "easy" definition that they need to make it more specific. For example: "Those bodies affected by the Sun's gravitational pull in such a way they form a circular type orbit around it shall be called planets. Those bodies affected by an individual planet's gravitational pull shall be called moons." Their defintion is simply too generic.
Music, my drug; dance, my ecstasy.
So, if the moon were reclassified as a planet, what would its name be?
Ceti Alpha 6?
Maybe it should get a real name anyway, instead of just a descriptive. Praxis I'm thinking, or Zoidberg maybe.
"We are all geniuses when we dream"
- E.M. Cioran
that's why the sea levels won't rise ... the farther away the moon is, the lower the seas ... and this should compensate for the ice melting..
although I always wonder what's the big deal, since icebergs are 90% submerged anyway, and ice takes more space than water (cause of the air bubbles)
I propose we move to a system of defining planets where if it's on the list labelled "Official Planets List by Old Astronomers Who've Served Their Time", then it's a planet, and then dissenters can simply be dealt with by using the standard answer of "It's not on the list - so it's not a planet". :-)
People are already arguing over things that may happen in a few billion years? I don't even buy green bananas!
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The energy to lift the Moon's orbit comes from the rotational energy of the Earth, which is limited. As the Moon gets higher the Earth rotates slower. There may not be enough energy to lift the Moon high enough to qualifty.
Remember when that radioactive waste dump on the moon blew up and sent big chunks of it all over the place? Yeah, that was some kind of fireworks. Good thing it was on our side of the planet when it happened or we'd have missed all the fun.
Too bad about that moon base that was on one of the smaller chunks. That thing really hauled ass. Oh well, so it goes.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
To be fair, it was a reasonable interpretation of your post to think you were saying "it won't be a moon because it will escape and go FLYING INTO SPACE!!1" instead of the intended point "if it no longer fits a definition, it isn't what's defined. This is news?". 'course, the AC was more than a bit condescending about it.
At first I thought TFA said a few million years and I started getting worried, then I reread it and now I'm ok. Whew, that was a close one!
This space intentionally left (almost) blank.
If the astronomers who thought of the new classification system really give a shit about reclassifying something that will happen in a FEW BILLION YEARS.
If we are even still on Earth in the year 3,000,000,2006 - that is.
Surely the reason why the Moon is considered a satellite of the Earth, rather than the Earth and Moon being considered a binary system, is because the centre of mass of the combined system is within the volume of one of the bodies {in this case, the Earth}? If the C. of M. was somewhere in the space between the two bodies, then they would constitute a binary system. Since the Earth weighs about 82 times as much as the moon, and the radius of the Earth is about 6.4 megametres, for the C. of M. to be just at the Earth's surface would require the Moon to be 82 * 6.4 = 524.8 megametres away from the Earth. {It's currently about 385Mm}. Further away would definitely make us a binary system.
Je fume. Tu fumes. Nous fûmes!
The problem here is our definition of "Planet" is fairly ambigious to start with. Just as "baby" can mean a tiny human between 0 and 2 years old or your girlfriend.
crazy dynamite monkey
It's kind of a race, isn't it? Eventually, the Earth will become tide-locked to the Moon and the orbit will stop changing. I wonder which will happen first?
Clear, Dark Skies
Because the IAU's definition is only talking about secondary bodies, not solar orbits.
Clear, Dark Skies
...but that would belittle the name of our moon, which is the Moon.
You gotta wonder if the person who submitted article had even read it.
That's exactly the model we're working with.
The problem here is that people want things to be neat and tidy and to be able to say "planet are not moons and asteroids are not planets and Pluto is a planet because it just is!"
This is the same thing that happens every time a biologist mentions that "species" is a vague and arbitrary term.
Clear, Dark Skies
A few billion years? Why should they care?
It was projected that in a matter of millions of years, the moon will cause the earth to stop rotating altogether. Without rotation, do you seriously think we will inhabit this planet?
For that matter, in a matter of millions of years, we should have developed a technology for making the earth rotate as fast as we wish, and moving the moon back where we want it to be. All it requires is enough rocket-power by even today's standards.
And over there we have the labyrinth guards. One always lies, one always tells the truth, and one stabs people who ask t
a sublight ship goes to the center of the galaxy and back, and when it returns the Earth has been moved to an orbit around Jupiter? (IIRC, we did it by mounting engines onto Neptune...)
Clear, Dark Skies
n/t
Maybe you should RTFA. The SPACE.com story is talking about in a few billion years, when the barycentre of the Earth-Moon system has moved above the surface of the earth. That would make the Earth and the Moon double planets. In a few billion years. The IAU FAQ you quoted was more concerned about right now.
Obviously, people care tremendously, which is why we ended up with this half-assed bandaid of a definition - which is an attempt to use a single word to describe three wildly divergent phenomena in a way that makes scientific sense and will pass muster with every pseudoscientist who thinks they have a right to an opinion on the matter.
The brutal truth is that there are at least three types of bodies that orbit the sun - rocky planets, gas giants, and bodies made up primarily of ices like Pluto and his friends. Lumping them together as a single thing is stupid; excluding bodies like Titan, Ganymeade and Europa from their "club" also makes little sense - but imagine bruhaha that would happen if astronomers simply stopped talking about moons and planets and started talking about rocks, gasballs and iceballs...
Clear, Dark Skies
Then you probably haven't heard for twenty years or so. The Hartmann/Davis/Cameron/Ward theory is pretty much the only one that accounts for the known facts (composition, angular momentum, etc.) and has been the standard explanation for decades. It's never been really seriously questioned since it was proposed in the mid 1970's. Are you perhaps thinking of the pseudo-scientific collision-with-Venus nonsense instead?
See the Planetary Science Institute's writeup for more details, or just Google.
--MarkusQ
Ditto for Pluto and Charon.
I am hopefully looking forward to this "Golden Age" in just a few billions of years, when our biggest problem definitely will be the fact, that the moon would be reclassified as a planet under the new IAU definition. ;-)
Greetings,
Chris
"An operating system must operate."
Calling Jupiter a "failed star" is like calling me a "failed super model" - I mean, yeah, there's some similarities between me and a super model but it's extremely unlikely anyone would ever mistake me for one.
IIRC, Jupiter has only about 1% of the mass needed to achieve fusion, so it's a long, long way from being a star. I, on the other hand easily have ten times the mass required to be a super model.
Clear, Dark Skies
A gravitation force between Moon and Sun already stronger than between Moon and Earth. Doesn't it mean that Moon orbits Sun?
He figured this out in 1960:
0 93556-7879220?v=glance&n=283155
http://www.amazon.com/gp/product/020000106X/002-4
Semantics, I mean. The IAU is attempting to maintain a logically consistent definition for a technical term of art which, unfortunately has an overlapping but divergent meaning in the public's mind.
This can happen a lot with scientific terms; psychiatric terms come to mind - "manic" and "psychotic" have technical definitions that are only vaguely related to what the public thinks those words mean...
Clear, Dark Skies
We'll be a Type III Civilization and we will be able to push the moon back into orbit.
What was your username again? -BOFH
Why can't something be both a planet and a moon? As far as I understand it, the new IAU definition of a planet is something that's in orbit around a star, is not a star, and is large enough for gravity to make it roughly spherical. A moon is something that's in orbit around a planet. So you could argue that our Moon is already a planet (it's in orbit around the Sun as well as the Earth). The same would apply to many other large moons in the solar system.
Unfortunately, the "There are nine planets, dammit, nine!" crowd would have collective aneurysms if we started classifying the Galilean moons as planets.
Even with this definition, there are estimates that we will end up with over 50 planets - the vast majority even further out than Xena.
Clear, Dark Skies
OF COURSE it would. It would no longer orbit the earth, so it would no longer be a moon.
Of course, they would be Binary Planets. And you just know Bi-Planet wouldn't go down at all well with some.
This smacks of an elementary-level understanding, I don't know why it made the front page. If you change the physical properties of a named object, and want to name it something else, who cares?
Smacks of those, who want do do away with Darwin, eh?
A feeling of having made the same mistake before: Deja Foobar
Till Galileo made it a generic term. Pity no one thought to maintain the trademark.
Clear, Dark Skies
Does Cruithne now get full moon status?
The "Moon": A Ridiculous Liberal Myth
My 1-acre plot on the moon will then be planetary property - worth MUCH more!
Now all I have to do is get four little green houses up there...
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Ok, can't wait to see how Colbert would botch this now.
would it be "M" or "L" as in "Planet Luna"? would it come before or after Earth?
Inquiring minds want to know!
M-V-E-L-M-J-S-U-N-P-C-X ?
"My Very Excellent Mother Just Sent Us Nine Pizzas" just isn't going to work anymore, is it?
There is much cruelty in the universe, John.
Yeah, we seem to have the tour map.
No, I'm just saying it was probably an honest mistake. Why be hostile, even if he was? An eye for an eye leaves us all blind.
1) Peace could be achieved in the middle east 2) Oil will no longer be our primary fuel 3) The war on terror will be over None of these qualify as news items. Honestly why does this matter at all?
. . . after the Moon becomes a planet, then a few billion years later Earth becomes a moon and actually orbits around the moon. How weird is that? ;)
Can I bum a sig?
If the moon going further away from the Earth causes the barycenter of Earth to drift outside its surface, then the Earth will be orbiting a point outside itself, with its orbit becoming greater the farther the barycenter drifts, until it peaks at one point. This is similar to Pluto constantly orbiting a point outside itself, as illustrated in this NASA chart hosted by Wikipedia. I think that when a moon begins to have that effect, it should be classified as a planet.
Currently, the Earth's barycenter is three-fourths of the way to its surface, causing it to sort of wobble, rather than fully orbit an invisible point. This is like an analogy: This is like a Chippendale stripper doing a pelvic thrust, rather than running around in a circle.
Earth's orbit around the sun currently makes the sun wobble in a barely perceptible fashion. Jupiter's orbit around the sun, however, causes the sun to orbit a point about 7% above its surface. I think that there should be a new class of planets for the purposes of describing a planet that makes a star orbit itself in this manner.
Clearly, all brown dwarfs orbiting a star would also have a similar or greater effect. The best way to describe it, in my opinion, would be by merely affixing "co-orbital" to describe a planet altering the sun's orbit in this fashion, or a brown dwarf orbiting a star doing this.
If this causes a planet to be "co-orbital" for only part of its orbit, or a natural satellite to be a planet for part of its orbit, in some eccentric situations, that's fine with me. There's one other issue with the new definition that makes me uncertain, though. EL61 is a "minor planet" that has a very oblong shape caused by its own orbit around the sun. If it were in a slower, closer orbit, its own gravity would almost certainly be enough to warp it into a nearly spherical shape. Should EL61 be considered a planet, despite its problem?
The problem with global warming is not the melting of ice bergs and ice sheets over the oceans. That is basicly a zero sum game in regards to the ocean level..The problem arrises when the Greenland and Antaritc ice caps melt and then all that 'additional water' ( flows into the oceans causing them to rise several hundred meters. That is the problem.
Undetectable Steganography? Yep, there's an app fo
Do you really think the definition of a planet will be the same in a couple billion years?
If you ask today, then the moon *is* a moon.
If you were to ask again in a billion years, then the moon 'will be' a planet.
Or rather, it might be a planet.
The moon could be reclassified as a planet EVEN IF IT STILL ORBITS THE EARTH. It depends on whether the center of gravity of the pair is inside the earth or not.
Yes, and? The point still stands. Do we think it wrong that, if the centre of gravity goes from inside the planet, to between the two bodies, such that we now have two bodies orbiting each other, we would no longer consider one of them a moon, but consider the pair as a twin planetary system?
Is it right that, if we discover systems with these twin (or more) planets, we have to always label only one of them a planet, and the rest as moons?
This article is basically "This definition is wrong, because if the situation fundamentally changes, we'll have to relabel some objects". Well, duh. If Jupiter suddenly undergoes fusion, we'll have to relabel it a star, but does that mean our definitions of star and planet are broken?
Oh come on, the only thing that will be here after the looming massive nuclear war will be highly evolved cockroachs. Thats assumimg an asteriod the size of north carolina doesnt slam into "our" planet and wipe out all life. Not to mention the possibility that sentient robots will take control of earth and enslave the human race in a virtual world to feed off our electrical impulses. Seriously, we got bigger shit to worry about in the next few billion years than our moon being classified differently.
Why don't we just get used to calling everything that orbits around another entity a satellite and get over this whole "planet/moon/sun" debate. Classifify the satellites by how massive they are and the material makeup? It would make a normalized database much easier to construct :p
Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
Instead of wasting time debating this, we need to focus our efforts on attaching giant rockets to the surface of the moon to correct the drift, so that our (childrens x 1,000,000) children can enjoy a traditional view of Earth's sky.
Don't astronomers have anything better to do? Shouldn't you be off astronomizing or astronomating somewhere?
If we launch all the militant pedantic astronomers into space I, for one, would be delighted to call them all planets.
It will happen in a few million years, not billion. Google the math:
distance of barycenter from center of Earth: 2,900 miles
radius of Earth: 3,960 miles
distance of barycenter from Earth's surface: 1,060 miles
same, expressed in inches: 67,161,600 inches
speed of lunar creep away from Earth: 1.6 inches / year
Time until the barycenter is on the surface: 41,976,000 years.
That is pretty dang short in the context of astronomy. Or even in the context of geology. I think it would be truly short-sighted (I use that word deliberately) for astronomers to decide that the Earth and Moon are not a binary planet today but will become one next week (in astronomical time).
The Earth and Moon are a binary planet, have been so for a long time, and will continue to be for quite a while. It would be good if astronomers gave up their traditional notions about this and publicly recognized the truth, because only until then will the geologists and evolutionary biologists begin to take the Moon's influence into account in their own areas.
Fair enough.
Clear, Dark Skies
"5. The IAU classifies objects based on their current properties. Specialists note that the Moon is receding from the Earth, and in a few billion years, the barycenter will reside in free space, outside the Earth. The IAU, at that time, can then reclassify the Moon as a 'planet.' "
"I'm not saying you're fat - I'm saying I just caught Stephen Hawking trying to measure your event horizon!"
Clear, Dark Skies
If a Democrat was President, this never would happen. Chalk this up to the ineptitude of the Republicans.
I have heard that it is more in the realm of 40 million years.
But that is a side issue. For those complaining about this classification process, just ask why we need classification in the first place, mere parlance and the ability for us to interpret and communicate ideas. The definition doesn't fundementally change the idea.
Some complete adshate was stumbling his site up saying how this classification was 'bad science' and when after 22 paragraphs of 'tearing it apart' and talking about how our moon could become a planet, his suggestion?
That we do not fucking classify what planets are. He didn't say it in that many words, but that was only because he didn't realise that most arguments are support to have a counterpoint, not just spout bullshit.
If we do not use orbit and mass (gravitational stability) what the fuck else?
Why don't we say the four biggest are planets? the smaller are not? We are dwarved by the bigger planets far more than we eclipse the newer 'planets'.
People are being tetchy and frivilous about this whole thing, and stepping over the issue of classification and what the fuck it means. Science mother fucker, do you speak it? Serioulsy. It is this narrowminded approach to 'scientific' debate that is all to customary and all to accepted.
Get the facts and the reasoning straight ffs.
http://vathena.arc.nasa.gov/curric/space/planets/
I cannot fucking believe I still have to write a fucking CAPTCHA to login. What fucking year is this? OMG we have a CAPTCHA let's put it on every motherfucking page. FUCK OFF COWBOYNEAL remove the code that requires the CAPTCHA is you are logging in and posting a comment. retard. (becauseif you are logged in your don't need to CAPTCHA) STUPID!
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...know what an adshate is, but you don't want to be one!!
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Ok... Here is a simple test to identify what is a planet and what is a moon:
Does the body in question primarily orbit the Sun, or does it primarily orbit another body?
THAT is as simple as it should be. It is a simple observation that can be made, and thus, a simple answer. But, these scientists have, somehow, managed to take such a simple idea and make it an extremely complicated analysis. An object either primarily orbits the Sun or it primarily orbits another planet. It is irrelevent where the barycenter is, because the object is still orbiting the planet. It's REALLY not that damn difficult to decide what the body is orbiting. The location of the barycenter is irrelevent. Of ourse, ALL of the objects in the Solar System are orbiting the Sun, but moons are orbiting objects that are orbiting the Sun. What object is orbing another object, and what object is having another object orbit around it? It's really quite that simple. But, alas, people who have spent the majority of their lives studying this have managed to screw it up.....badly.
This is a prime example of what happens when educated people try to make sure that everybody knows that they are smarter than everybody else in their field of "knowledge". The problem is, they just end up making idiots of themselves in the end.
-----
Sig Sauer.
Knowing Google's lust for data collection, the Soviet Union is still alive and well inside the psyche of Sergey Brin....
So, we'd rename it 'The Planet'? How's that going to work? "Hey diddle diddle, the cat and the fiddle, the cow jumped over the Planet..." Will no one think of all those lonely women making childrens' greeting cards?
Or in my case, both.
In a few billion years, the USA may even have changed from Imperial to Metric units! :)
Environmentalism is the new Victorianism. Everyone ties on a green corset and pretends we're virtuous.
I've seen some really, really, really lame stories posted on Slashdot, but this one has to be the most retarded I've seen yet. The moon will be classified as a planet in a few billion years under the new proposed definition. I don't know where to begin to say how utterly stupid and asinine that sounds. Because of the Moon is so large relative to the Earth, some astronomers refer to the Earth-Moon system as a double planet. Charon as a moon is even larger relative to Pluto and so could also be called a double planet.
There are so many exotic objects in space that run the whole spectrum of sizes from stars to brown dwarfs to planets to moons to asteroids and comets it is sometimes hard to say where does one begin and other end. We should use working definitions for purposes of scholarly debate. And say this is the best description we have to date of what a planet is or is not. And for those objects that fall into a grey area we may have to decide what they are on a case by case basis. To say the Moon will be a planet in a few billion years is about as useful as saying the Earth won't be a planet in a few billion years when the Sun expands and becomes a red giant and vaporizes it. So what? That's not what it is today.
"You'll get nothing, and you'll like it!"
Well since it's made of such yummy cheese, we'll surely have eaten it all by them.
The days of the digital watch are numbered.
In Soviet Russia, the Moon Lands On You
What? The moon a planet?? Won't someone think of the children???
Only North Koreans call the moon a planet.
ok folks I know there's more I just can't remember right now.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Prague is getting pretty crazy here: Pluto likely to become that demoted pluton. Poor, poor Pluto! http://www.space.com/scienceastronomy/060818_plane t_newprop.html
Oh, NO! This is a disaster, how could they make such a horribly shortsighted definition that will be alter the definition of our moon in only a few billion years?
Man, the post-human super-terrestial inhabitants of this solar system are gonna be pissed that they have to redefine the name of that uninhabitable incinerated, waterless, solar-flare-battered planet's satellite! I bet they'll be so peeved, they go back and relearn English too, just so they can curse it properly before the orbits of everything in the solar system begin to destabilize.
If the new definition is adopted, it won't last for long. We will redefine what a planet is and is not when Humans finally explore the sol system and interstellar space for the first time.
/. Mars comes after the Earth. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and UB313.
BUT I hope the IAU holds off until the satellites visit Pluto in few years. It's purpose is to study pluto and we can use it to determine if Pluto is actually a planet. And if pluto gets dropped as a planet, We will still have nine planets. Scientist are confident that UB313 is larger then Pluto. So UB313 could become our ninth or tenth planet in the SOL system.
Anyways, The moon is needed (tides). And even if it did move outside Earth's gravitational pull, It will still be called the Moon or 'Cheese' world. Old habits die hard.
And those worried about Sol becoming a red giant. By the time that happens, a Human colony is most definitely ensured.
FYI: To some idiots on
\
The earth is not genuinely round. Most everyone who paid attention in their freshmen science class in high school knows that it's bulges about the middle due to centrifugal momentum. Same for Jupiter. If you really want to get specific, there's tons of mountains and cliffs on earth that further screw up the roundness and even the convexness of the surface, but that's just getting silly. Bodies like Demos and Phobos are less round, but gravity must have some effect on their shape. Also, material matters. An icy body like Pluto is thought to be would form into a round shape at a lower mass than a rocky one.
The new definition definitely has a good element of precision to it, but consider two bodies of the same mass and composition where one is "rounder" than the other, perhaps due to a major impact event or something (I believe one of Saturn's moons is like this). There's no real difference that distinguishes one as a planet and the other as an asteroid, at least not like there is a difference between carbon and nitrogen. It's just going to be a fact of astronomy things are not as discrete as in some other fields. I guess they felt they had to draw a solid line somewhere for the definition, but that line was still arbitrarily drawn and it's not quite solid. Anyway, I'm sure kids for another generation or two will still memorize the 9 historical planets. Then teachers may slowly start making them memorize the 8 major planets (or perhaps Ceres will take Pluto's place in the list) and remember that there are dozens of smaller planets. The definition also, as near as I can tell, still leaves the upper end in question. At what point is a body a star rather than a planet? Supposedly some of the extrasolar planets found are large enough to initiate fusion of deuterium at their cores.
There once was an orbiting entity /.-ers snickered
Neither planet nor moon in identity
The IAU bickered
It was too close to Earth; no Pluton, pity.
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
Well, yeah, basically they'd both be orbiting that center of mass somewhere between the Earth and the Moon, which in turn would be orbiting the sun. The center of mass would still be very close to the Earth... From the perspective of someone on Earth, though, it would look like the Moon's orbiting the Earth.
---GEC
I'm but the humble pupil, seeking to snatch the scratchbuilt pebble from the master's fully articulated hand
People: Reverend Sun Myung Planet
Cults: Planeties
Sports: Planetshot
Classic TV: One of these days, Alice... POW! Straight to the planet!
Urban Legends: The planet is made of green cheese
Songs: By the light, of the silvery planet
Okay, one more and then I'll stop:
Stuff bored redneck kids do on the highway: Chuck a planet
Is it....Satan?
"So what planet are you from?"
"I am from planet Moon."
"What?"
"@#)$*(@#($&*(, I told you LAST TIME What's on second!!!! Graaaah!"
You see? You see? Your stupid minds! Stupid! Stupid!
Inignot: Hello, Carl, I am Inignot and this is Err.
Err: I am Err.
Inignot: We are Mooninites from the inner core of the moon.
Err: You said it right.
Inignot: Our race is hundred of years beyond yours.
Err: Man, you hear what he's saying?
Inignot: Some would say that the Earth is our moon.
Err: We're the moon.
Inignot: But that would belittle the name of our moon, which is: The Moon.
Err: Point is: we're at the center, not you.
Since the Democrats and the Republicans are essentially the same party nowadays. I suggest republicrats.
By this new definition, a planet is a planet, and a moon is a smaller planet orbitally locked to a larger planet.
As the center of the system moves out of the Earth, there will be a moment in time when it's at just the right height above the surface. If you were to be standing there at that moment, then the Earth would actually be revolving about you!
READ the US Constitution, the Bill of Rights and the other amendments! http://lcweb2.loc.gov/const/const.html
With the double planets Pluto and Charon they are both orbiting around a point that is between the two. However, the point around which earth and it's moon orbit is within the earth, therefore it's a moon, not a planet
If the apple tree in my front yard, over billions of years, grew to 20,000 miles in diameter and somehow launched itself into orbit around the sun, IT TOO WOULD BECOME A PLANET! ... how about we stick to worrying about reality instead of crackpot hypothetical situations?
Comment of the year
It's backing away, in preparation for fight or flight has yet to be determined.
No, it's not that. Didn't you hear? They have no bananas! They have no bananas today...[walks off crying]
-- Homer J. Simpson
Not one reference to 'Space 1999'.
Sheesh.
... if, somehow, it gets ejected from the solar system. Not a completely unlikely event.
Soon after breaking away from Earth, the inhabitants of the moon base discovered a new form of space drive, powered by pompous acting, cheesy special effects and script continuity errors. They now roam the galaxy at will!
Soylent Green is peoplicious!
When I was in school 30 years ago, I was taught that the Earth and Moon were binary planets. This must have been fairly accepted since it came up more than once in both Elementary and High School. So for me this new definition changes the "Moon" from planet to moon, at least for a while. I can't remember the details of the definition applied, but it was something like the center of rotation being outside the core of the of Earth.
Oh you mean Luna, casue "The Moon" isnt the only one, ya know.
Will women stop having their periods?
The Moon cannot escape the Earth's gravitational field (unless there is a very large external perturbation). As the Moon slows it will orbit increasingly farther out, UNTIL it is traveling too slowly to maintain any orbit, at which point it will spiral in until broken up by tidal forces. Earth will get rings (and more than a few major impacts). If the Moon were traveling at escape velocity, it would already have departed. Since it isn't, it can't (on its own).
There may be a bit of a race condition between the Moon's orbital mechanics and the Sun's progression along the "Main Sequence", which will put it into a "red giant" phase where the extended "surface" may be near, or beyond, Earth's orbit. At that point, both parts of our Earth-Moon system will experience significant drag and spiral into the Sun's core.
It's a boneheaded definition, unnecessarilly complicated.
A stellar object: any object of sufficient mass (Z) to become a star, or the remains of such an object (e.g. black dwarf, black hole)
A brown dwarf is an object of mass greater than Y, but less than Z
A planet is a non-stellar object of at least mass X but less than Y, which may or may not be orbiting a stellar object or brown dwarf (it can be floating free in space, beholden to no star).
A moon is an object orbiting a non-stellar object of larger mass.
A planetoid is an object greater than mass W but less than X
An asteroid is an object with mass less than W but greater than V.
A dust mote is an object with mass less than V
(add more definitoins as desired. Stones, rocks, pebbles anyone?).
Obviously a planet can also be a moon if it is orbiting another planet of larger mass. Feel free to define a lower bound for the definition of a moon, to exclude ring particle material, small artificial satellites, etc. But really, this approach is very straightforward and holds up regardless of prevailing theory, and doesn't involve any boneheaded definitions that result in the Earth having a moon but Pluto having only a "companion planet so diminutive as to only be called a planet by pedantic astromers working from boneheaded defintions in a desperate attempt to keep pluto on the list of planets".
Definitions of planets involving barycenters, theories of formation, and orbital characteristics are IMHO flawed. Mass should be the definiting factor, with death matches between astronomers of dissenting camps to be fought to determine exact values of V, W, X, and Y. Z should be obvious based on phsycial requirements to sustain a stellar fusion reaction.
This took me five minutes of typing. Why are these geniuses having such a difficult time of it?
The Future of Human Evolution: Autonomy
Moving away at its current speed, it would have taken 10bn years to move from the Roche limit to its current position. (In rough figures: 4*(10^8)m / (0.04m/year) = 10^10years)
But the moon is drifting away due to tidal effects. So it would have been drifting faster in the past. Taking that into account, the MAXIMUM possible time the Moon could have been orbiting earth is less than 1.5bn years.
So how come many scientists think the Earth-Moon system is 4.5bn years old? Maybe they just haven't done the math.
Of course from the perspective of someone on Earth the Sun orbits the Earth anyway, so it is all a moot point...
What about the point of view of someone on the sun? Had you thought about that? I think it'd go a little something like this...
"Well, let's see, where's the Earth... Ah, there! Now it seems to be moving around and - aw, shit, my eyes just got vaporized."
---GEC
I'm but the humble pupil, seeking to snatch the scratchbuilt pebble from the master's fully articulated hand
Earth's moon is drifting away from us
Of course it is! It made news in 1975:
http://www.space1999.org
Educate me, what does it mean ?!?
--- I am known for the ones who want to find me on the net. Is that a privacy risk or a privilege? One might wonder..
http://en.wikipedia.org/wiki/Double_planet
Scroll down to the part about Isaac Asimov
Asimov said we are inhabiting a double planet system right now.
Look, mother Earth has been coddling luna for so long now. Now I know our on-again-off-again romance with Mars has been hard on her, but she really needs to think about leaving the nest one day and striking out on her own. It's about time she grew up, got a job - maybe a steady boyfriend. I hear Ganymede is doing well. Or how about that nice lad Titan? Jupiter has been so successful with its moons. Honestly, we only want what's best for her. She should count her blessings. Before you know it, she'll be off running on some ecliptic orbit with that good for nothing Pluto. Mark my words.
When speaking about barycenters it seems necessary to have at least two bodies in the system, it is a relative term so the dicussion has to be focused only within the system within which the context is. The sun is orbitting some cosmically larger system, I am not an astronomer but it's more than likely that if you could pick one object that the sun orbits around, the barycenter of the sun and that object does not fall within that object, is the sun also a planet?
We'd have planet Brando!
*crickets chirp*
What, too soon?
Just because you can mod me down, doesn't mean you're right. Shoes for industry!
I've never been quite sure that there was a good technical argument for not simply calling the earth-moon system a double planet, so let the moon be a planet. Who does it hurt... it's just a name.
won't much matter in 5 billion years - the sun has a hydrogen burning lifetime of about 10 billion years - and it is about 4.6 billion years old now - when it runs out of hydrogen and has to start burning helium and becomes a red giant, the sun will expand to include the orbit of Mars - and Mercury through Mars including the moon won't be planets anymore either by this definition, or as much to look at..
Well... they are drifting away from the rest of the world, yes?
nm
Ops, I shuld have usd the prevuwe but in.
Or does it make it a Comet, a meteor?
Ops, I shuld have usd the prevuwe but in.
(Please check mine:)
The barycenter of earth moon can not escape the surface of the earth.
Its a late post, and i wasted 2 minutes to do the math but here it is:
Moon has to be 822 000 km away for barycenter to lay on the surface on the earth. Today r=380 000 km
earth rotational inertia is transferred to the moon (tidal) nonelastically. The earths rotational inertia is only twice the moons orbital rotational inertia. This is not enough to 'push' the moon that far away.
The result should be a system with an earth day = a month = a moon day = 47 current days, and moon-earth distance ~510 000 km.
The moon is still a moon, and no planet per definition.
"Fix it"
We just haul up and lasso that sucker! Then we drag the lunar load back down a bit so the barycenter is still within earth, then we tie the rope to a tall tree so that the moon doesn't float away again.
Or we can build a big earthen wall, tall enough that the barycenter of the moon stays within it. Kind of like a tight-fitting planetary ring.
I like my coffee the way I like my women - roasted and ground up into little tiny pieces.
Hi,
it is possible that today (August 24th 2006) will IAU issue the final decision. Visit Live broadcasting announcement portal to tune up live transmission from Prague.
MK