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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!
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"
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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.
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.
If you'd bothered to RTFA, you'd find that the moon would be reclassified as a planet when the systems center of gravity no longer resides inside the Earth.
I would gladly send my kid to this elementary school if they could prove that they could teach concepts like orbital decay and barycenters to to nine-year-olds.
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.
"I would gladly send my kid to this elementary school if they could prove that they could teach concepts like orbital decay and barycenters to to nine-year-olds."
I would only send my kid there if they LEARNED it. I have a feeling they most nine-year-olds would be picking boogers during that class.
If a nation expects to be ignorant and free, in a state of civilization, it expects what never was and never will be.-TJ
I already consider the moon-earth as a bi-planetary system. What's the big deal with these definitions, anyway? No matter where you draw the line, there will always be cases where there will be discussion. Like the criterium that the object has to be "nealy spherical" because of it's own gravity. Lots of planetoids are somewhere on this vague border.
Comets, asteroids, planets, stars, they all have grey areas between them.
"It's too bad that stupidity isn't painful." - Anton LaVey
Wrong, wrong, wrong! Just RTFA. The moon does not have to escape the Earth's gravitational pull in order to be re-classified as a planet. The only thing that would be necessary (according to the new definition of a planet) is that the Moon moves further away from the Earth, just enough so that the barycenter of the Earth-Moon system is above the surface of the Earth. The Moon would still orbit the Earth. Obviously, the moderators who gave a +5 Insightful to your comment have not read the article either.
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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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.
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This is called a Twin Planet. And no it would nolonger orbit the earth the earth, the "moon" would orbit eachother at a common point. Either way, I see no reason that once we have this designation of moon vs planet why we should be so beholden of "our" moon that we can't accept it nolonger being a moon. We shouldn't change the definition just to fit some popular idea.
It was my understanding that the moon affects the level of the tides, not the mean sea level, which is far more a product of the Earths gravity and dependant sea water pressure/density.
Yes all those scientists must have missed that one, eh?, I am glad there are informed people like you in world to set them straight.
You are assuming that all the ice is in the seas, which it is NOT. A large amount sits on land in the form of Ice Shelves, there is enough to cover an entire contient (Antarctica) as well as most of Greenland and Canada, not to mention all the ice in Glaciers. As all this melts (and there is enough in Antarctia to contain 90% of the worlds fresh water) it wil flow into the sea and the sea level will rise, that is 'the big deal'.
But don't worry I am sure Mr President will give you a big pay rise for that wonderfully dismissive comment on the effects of climate change.
If this were really happening, what would you think?
The moon does not have to escape the Earth's gravitational pull in order to be re-classified as a planet.
Well thank God for that. My head would probably asplode if they decided Mars wasn't a planet, although the Big Ass Red Round Thing has a nice alliterative ring to it.
KFG
That's not how the definition works - if a coorbital body has the barycenter of its minor orbit with its companion body outside either body, it's a planet. If it is too small to ignite fusion and orbits a star, it's a planet, regardless of whether the barycenter of the planet-star system is inside the surface of the star.
I'm almost 26 and I'm picking boogers right now while reading these comments. (I'm serious)
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
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.
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
If what?
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
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.
yea it would be annoying if astronomers stopped paying attention to space and only talked about balls and gas
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I think Asimov said something like this in one of his thousand books. His argument was that, unique among (known) moons, Luna's orbit is always curved towards the sun, making it more of a coplanet than a proper moon. But I can't remember which book it was, unfortunately.
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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?
Consider 2 bodies of equal mass seperated by a distance of X.
The Centre of mass is right in the centre of the space between them.
The distance X increases by 1 unit, does the centre of mass also increase by 1 unit?
Adjust this equation to put it into earth/lunar context and you will understand why scientists don't just "google the math".
liqbase
"Of Time and Space and Other Things"
Which was a collection of essays on various interesting science stuff, though I don't know if any of it was published seperately.
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?"
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.