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The Moon Has a Fluid Outer Core

Soulskill posted more than 3 years ago | from the marshmellowy-filling dept.

Moon 127

mapkinase writes with this excerpt from Discovery News: "The Apollo Passive Seismic Experiment recorded motions of the ground from moonquakes and other activities generating sound waves until late 1977. The network was too limited to directly monitor waves bouncing off or scattered by the moon's core, leaving scientists dependent on more indirect techniques, such as measuring minute gravitational changes, to craft a picture of the moon's interior. Those models turned out to be pretty accurate, says lead scientist Renee Weber, with NASA's Marshall Space Flight Center in Huntsville, Ala. The new research confirms the existence of a solid inner core and liquid outer layer, similar to Earth's. Unlike Earth, the moon also has a partly melted, mushy layer over that."

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Wow (5, Funny)

Anonymous Coward | more than 3 years ago | (#34808170)

Molten cheese?

Re:Wow (3, Insightful)

Pharmboy (216950) | more than 3 years ago | (#34808324)

More like a chocolate covered cherry.

Re:Wow (1)

Anonymous Coward | more than 3 years ago | (#34809442)

Molten cheese?

Fondue?

Re:Wow (1)

SeaFox (739806) | more than 3 years ago | (#34813396)

That's no moon! It's a fondue pot!

Re:Wow (0)

Anonymous Coward | more than 3 years ago | (#34809904)

Is that American cheese or European?

Re:Wow (3, Insightful)

Low Ranked Craig (1327799) | more than 3 years ago | (#34810354)

Most "American cheese" isn't really, legally speaking, cheese.

I say this as an American that loves cheese

Re:Wow (1)

metaforest (685350) | more than 3 years ago | (#34813772)

"Homogenized, pasteurized, cheese food."

Food for cheese?

"Homogenized, pasteurized, cheese food substitute."

Food for cheese that is intolerant of, 'cheese food?'

The mind boggles.

Re:Wow (0)

Anonymous Coward | more than 3 years ago | (#34810472)

Does one grip it by the husk?

Re:Wow (1)

spinctrl (815494) | more than 3 years ago | (#34810538)

Fondue.

Re:Wow (1)

fishexe (168879) | more than 3 years ago | (#34812396)

Molten cheese?

That's a long way to dig to get your fondue. Even less worth it if your plan is to make nachos.

irish guy (-1)

Anonymous Coward | more than 3 years ago | (#34808198)

first

Amazing stuff (1)

Anonymous Coward | more than 3 years ago | (#34808228)

I thought the solid Moon was a done deal. Was I misinformed, or is this groundbreaking science (forgive the pun)?

Re:Amazing stuff (5, Informative)

Artifakt (700173) | more than 3 years ago | (#34810264)

Forgiven.
1. Some theories said the moon had to be solid. It's smaller than Earth so it ought to have cooled faster. It has a lower average density than Earth so it shouldn't have lots of radioactive elements in its core, adding heat as they decay (Since all the long lasting radioactive isotopes are dense metals).
2. You were probably informed that its calculated density showed the Moon couldn't have enough pressure near its center for an inner core to be crystaline iron, with an outer core of molten iron. That's what we think Earth is like. It explains our strong magnetic field, and its lack would explain why the Moon (and Mars, Mercury and Venus, also all somewhat smaller than Earth) doesn't (don't) have a similar magnetic field (s). That's only partly changed. This evidence suggests the moon has an inner core and outer core that are respectively solid and liquid (like Earth). It has a boundary layer above the outer core that goes gradually from liquid to slushy to sort of solid (unlike Earth, where the next boundary is pretty sharply defined). It has a solid crust (like Earth). So what's different besides that interesting slushyness? Iron. Earth's core is probably nearly all Iron, packed into a very regular crystal. Huge chunks of core have been pressurised enough to erase the irregularities between smaller crystals and merge them into one crystal structure wherever possible until you get to the top bit where it becomes more a bunch of discreet crystals and then molten Iron in the outer core. The Moon's core appears to be solid surrounded by liquid, but it doesn't appear to be almost all Iron - it still has much lighter material mixed in compared to Earth's core. So, if your high school geology teacher said the Moon couldn't have a solid Iron inner core with the vastest part of it in a regular crystal state, and a molten outer core, they may still have gotten it right, but if they went farther and said it couldn't be solid surrounded by liquid or couldn't be liquid at all, they definitely went too far in explaining the limited observations of the time.
3. Some of the Selenologic data comes from Apollo. Some comes from more recent efforts like the south polar impactor mission. Not all that data matches, so it's probable this all needs more work and new instrumentation to be more confident we eventually get the whole model right. What's happened here is we have gotten closer to making the kind and quality of observations we have made to Earth itself during many earthquakes and other events, but arguably we are still not 100% caught up.

Re:Amazing stuff (2)

Nyeerrmm (940927) | more than 3 years ago | (#34810862)

We'll hopefully have a lot more data this time next year as well. The GRAIL mission, which will map the gravity of the moon and get a better sense of it's internal structure, is launching in the fall.

Thanks for your detailed explanation. I'm supposed to start working on that mission soon, and this gave me a much better grasp on the background.

Re:Amazing stuff (1)

justin12345 (846440) | more than 3 years ago | (#34812162)

Thank you for the very informative post. I was just about post "if it has got a liquid core layer, where's the magnetic field" so thank you also for answering my stupid question before I got a chance to ask it.

Re:Amazing stuff (2)

AfroTrance (984230) | more than 3 years ago | (#34812532)

(Since all the long lasting radioactive isotopes are dense metals).

The decay of potassium-40 is the major contributor of heat within the Earth. Potassium isn't a dense metal. Also, there is a theory that a significant amount potassium could exist in the Earth's core [physicsworld.com] .

Maybe potassium-40 is the reason why the moon does have a liquid outer core?

Re:Amazing stuff (2)

perrin (891) | more than 3 years ago | (#34813790)

Nice post. Just thought I'd point out one small mistake -- Mercury does have a magnetic field, despite its tiny size! Even though it is only 1% of the strength of Earth's, it envelops the entire planet and shields it from the solar wind, just like on Earth, and so much unlike the Moon, Mars and Venus.

Darn (1)

$RANDOMLUSER (804576) | more than 3 years ago | (#34808260)

I was hoping for caramel.

Re:Darn (0)

Anonymous Coward | more than 3 years ago | (#34808300)

I always thought it was made of cheese.

Re:Darn (0)

Anonymous Coward | more than 3 years ago | (#34809092)

Fondue!

Re:Darn (1)

PolygamousRanchKid (1290638) | more than 3 years ago | (#34809508)

I was hoping for caramel.

It's "candy-coated popcorn, peanuts and a prize."

Buzz Aldrin already got the prize, so if you plan to visit the Moon, don't be disappointed when you can't find it.

When he was confronted by one of those Apollo Moon landing hoaxer kooks, who screamed, "Show us the prize!", the 70+ years old Aldrin responded by knocking the kook's teeth out.

If I ever meet Aldrin in a bar, I'm buying.

Heat energy. (0)

Anonymous Coward | more than 3 years ago | (#34808314)

Where does the energy come from to keep the layer fluid?
I thought the moon had cooled and solidified because it does not have the decaying Potassium Uranium and Thorium isotopes to provide heat.
Does it get it's energy from being squished by gravity, like the moons of Jupiter, or does that require multiple moons?

Re:Heat energy. (2)

MichaelSmith (789609) | more than 3 years ago | (#34808396)

I suppose a bit of heat comes from being swung around in the sun's gravitational field, but the crust would feel that more than the core. I don't see why there can't be a lot of radioactive material in the core. Additionally the Apollo heat flow experiment should have shown how much heat is actually being lost through the crust. Maybe the core hasn't had enough time to cool entirely. Its a pretty small core.

Re:Heat energy. (1)

icebike (68054) | more than 3 years ago | (#34808460)

What about the Earth's gravitational field? Wouldn't that have a significant effect as well?

Re:Heat energy. (1)

MichaelSmith (789609) | more than 3 years ago | (#34808540)

Well yeah. Its because the moon is in orbit around the sun and the moon at the same time. The orbit has to be fairly eccentric around both so the changing intensity of both fields raises small tides in the lunar crust.

Re:Heat energy. (1)

icebike (68054) | more than 3 years ago | (#34808600)

Would the fact that the moon always has the same face towards earth (tidally locked?) accentuate or mitigate any effects of Earths gravity in heat generation withing the moon?

Re:Heat energy. (5, Informative)

MichaelSmith (789609) | more than 3 years ago | (#34808722)

I suppose its part of the picture. I read somewhere that the core is offset towards the Earth by about 1 km. The moon does wobble slightly. Telescopes on Earth can see about 60% of the lunar surface by observing at the right times. The sun will be continually pulling at the moon to point towards it.

Re:Heat energy. (2)

Hognoxious (631665) | more than 3 years ago | (#34808656)

the moon is in orbit around the sun and the moon at the same time.

What's that, the semiautolunacentric model?

Re:Heat energy. (1)

MichaelSmith (789609) | more than 3 years ago | (#34808820)

the moon is in orbit around the sun and the moon at the same time.

What's that, the semiautolunacentric model?

Consider Janus and Epimetheus [wikipedia.org] . Do they orbit each other, or do they orbit Saturn? Both statements are true. This is also the case for the Moon and the Earth. Its really a difference of degree.

Re:Heat energy. (1)

Hognoxious (631665) | more than 3 years ago | (#34808976)

Consider Janus and Epimetheus. Do they orbit each other, or do they orbit Saturn?

They both orbit themselves, according to your theory.

Hint: try actually reading what you wrote above instead of being such a smug smartasss for once.

Re:Heat energy. (1)

Pseudonym Authority (1591027) | more than 3 years ago | (#34809094)

Pardon my intrusion, but I think the joke that Mr.Hognoxious makes revolves around a subtlety in your post.

the moon is in orbit around the sun and the moon at the same time.

See, that would >imply that the moon revolves around itself, hence the joke.

Re:Heat energy. (1)

newcastlejon (1483695) | more than 3 years ago | (#34808584)

What about the Earth's gravitational field? Wouldn't that have a significant effect as well?

I think the point was that it's going around the sun so it has sunlight shining on it. IANAA but I don't believe the Moon is subject to any significant 'kneading' like Titan; I imagine this is because the Moon is so large compared to the planet it's orbiting.

Re:Heat energy. (2)

lxs (131946) | more than 3 years ago | (#34811810)

There is no (more) kneading because the Moon is tide-locked to the Earth. Any deformity is permanently fixed in place.

Re:Heat energy. (1)

sidyan (110067) | more than 3 years ago | (#34813496)

Wrong: see Libration [wikipedia.org]

Re:Heat energy. (1)

Yvanhoe (564877) | more than 3 years ago | (#34809666)

What about the same reason that keeps the inners of the Earth warm : nuclear fission ? After all, the kaguya probe has found decent amounts of it on the moon's surface (one of the most underrated science news of the recent times, imho) so it is not far fetched to imagine it containing a decent proportion near its core. Especially if it is liquid.

Re:Heat energy. (2)

John Hasler (414242) | more than 3 years ago | (#34808464)

> Maybe the core hasn't had enough time to cool entirely. Its a pretty small core.

A smaller planet cools faster.

Re:Heat energy. (1)

MichaelSmith (789609) | more than 3 years ago | (#34808560)

> Maybe the core hasn't had enough time to cool entirely. Its a pretty small core.

A smaller planet cools faster.

Yes.

Re:Heat energy. (1)

drinkypoo (153816) | more than 3 years ago | (#34813558)

A smaller planet cools faster.

All else equal, sure. But if one of those layers is insulative (at least compared to the larger neighbors) then all bets are off. The Moon is known to be less dense than the Earth, so you would expect the rate of thermal transfer to be less.

Re:Heat energy. (1)

khallow (566160) | more than 3 years ago | (#34808474)

My understanding is that it still has radioactives. Also there's modest tidal forces acting on the Moon (mostly from the Sun). I guess the last heat source would be heat of crystallization of the liquid core. I'm a bit surprised that the core is still liquid. It must be that the Moon is a great thermal insulator right now.

Re:Heat energy. (2)

MichaelSmith (789609) | more than 3 years ago | (#34808588)

It must be that the Moon is a great thermal insulator right now.

Reminds me that Astronauts working on the surface had to keep their suits as clean as possible to help stay cool. Partly because being dark means you collect more heat from the sun but also because the dust is a good insulator. If the crust is made of the same stuff there won't be a lot of heat flowing through it. I also read that the daytime heat on the moon is gone one metre below the surface.

Re:Heat energy. (3, Interesting)

khallow (566160) | more than 3 years ago | (#34808728)

I also read that the daytime heat on the moon is gone one metre below the surface.

Keep in mind that daytime heat has only two weeks to penetrate before it is replaced with some serious nighttime cooling. You wouldn't have to go far down before the heating and cooling tend to cancel each other out.

Re:Heat energy. (0)

Anonymous Coward | more than 3 years ago | (#34809110)

Also there's modest tidal forces acting on the Moon (mostly from the Sun).

Bullshit. It should be obvious from the inverse square law that a closer object exerts a greater difference between the near and far sides than one further away.

If the sun was exerting a greater tidal effect then how come it keeps the same side facing Earth?

Re:Heat energy. (2)

khallow (566160) | more than 3 years ago | (#34809590)

If the sun was exerting a greater tidal effect then how come it keeps the same side facing Earth?

The sun doesn't and your observation is correct. But for heating purposes, the Moon is almost static with respect to the Earth. There's a little rocking, but nothing significant. On the other hand, the Moon's orientation with respect to the Sun is still effectively a rotation every four weeks. So even through the Earth's tidal force is much stronger, the Solar tidal forces probably contribute more to internal heating. I could be wrong about this since I haven't given it a great deal of thought, and the Earth's tidal forces may be providing much more heating than I expect.

Re:Heat energy. (1)

amRadioHed (463061) | more than 3 years ago | (#34812560)

It's obvious that the OP was talking about compression on the moon from tidal forces, not just tidal force. Since the moon is in tidal lock with the earth this is basically zero for earth. And since tidal forces actually follow an inverse-cube law, not inverse-square, the tidal compression from the sun is not really worth mention either.

Re:Heat energy. (1)

Teancum (67324) | more than 3 years ago | (#34814326)

Tidal forces from the Sun upon the Earth are sufficient to be noticed and a significant factor when calculating what the daily high tide is going to be, and its impact can usually be measured on the order meters in tidal height on a daily basis. I consider that to be substantial.

The Moon is for all practical purposes at the same distance, although a bit smaller so the tidal forces from the Sun will be reduced... not due to the distance from the Sun itself but rather the sheer size of the Moon. And the Moon is still a pretty big place... we aren't talking something the size of Phobos or some other insignificant rock... the Moon does exhibit hydrostatic equilibrium and is on the same order of size as places like Ganymede, Callisto, Io, and the other largest bodies in the Solar System. IMHO it ought to be classified as a dwarf planet.

POWER! (0)

Anonymous Coward | more than 3 years ago | (#34810246)

It also means that we can drill in various places, and get more than enough heat to run a base. That will be important if we are going to try and move around the moon and not just the poles.

Now, what is needed is to check to see if Mars has a Molten core. If so, then we have our power to colonize it.

Re:POWER! (1)

khallow (566160) | more than 3 years ago | (#34810614)

Now, what is needed is to check to see if Mars has a Molten core. If so, then we have our power to colonize it.

The absence of a planetary wide magnetic field on Mars is a negative indicator. There still be a hot core even if it isn't molten. So plenty of geothermal energy.

Re:POWER! (0)

Anonymous Coward | more than 3 years ago | (#34810680)

Actually, the lack of a magnetic field could very well be an indication of a flux (as in the poles are changing). The fact remains that we do not even have a grasp of our own planet, let alone others.

With that said, the supposed lave tubes that have been found would be a positive sign.

Re:POWER! (0)

Anonymous Coward | more than 3 years ago | (#34813132)

That is a good idea, however ...

Iron core - 240 Km
Fluid layer - 90 Km
Molten layer - 150 Km
After that the solid layer starts. Considering that the moon radius is around 1700 Km, that gives about 1200 Km of solid outer material. The question is if enough usable energy makes it close to/near the surface.

Thoughts ?

Re:Heat energy. (5, Interesting)

RsG (809189) | more than 3 years ago | (#34808494)

IIRC, there's still some debate as to how much of the interior heat of the Earth is due to radioactive decay and how much is residual heat leftover from the planet's formation. Remember that the Earth/Moon system originated as two bodies of similar mass that collided a few billion years back; both would have been fully molten, surface to core, when the proverbial dust had settled. Millennia would pass before either had a solid surface.

It might be that the internal heat of the Earth is partly residual, with radioactive decay delaying cooling by adding more heat. Regardless of the proportion of residual to radioactive heat, the moon should be less molten than the Earth, if only due to the square-cube law dictating the Earth will cool more slowly. So the science in TFA is actually pretty interesting.

Re:Heat energy. (2)

frieko (855745) | more than 3 years ago | (#34809378)

Before the discovery of radioactivity it was estimated that the Earth would only take 20MA to reach its current temperature from a fully molten state. So the internal heat is almost entirely radioactive, meaning that the degree of molten-ness depends mostly on composition, not square-cubiness. Also, exotic is when you use an endangered macaw not a chicken.

Re:Heat energy. (3, Informative)

John Hasler (414242) | more than 3 years ago | (#34811136)

> the degree of molten-ness depends mostly on composition, not square-cubiness.

The rate of heat production is proportional to volume while the rate of heat loss is proportional to surface area so equilibrium temperature is proportional to the 3/2 power of diameter.

Re:Heat energy. (1)

drinkypoo (153816) | more than 3 years ago | (#34813568)

The rate of heat production is proportional to volume while the rate of heat loss is proportional to surface area

...as well as density and the density and temperature of the neighboring material.

Re:Heat energy. (1)

imsabbel (611519) | more than 3 years ago | (#34814858)

But if you consider that the average distance to the surface (for heat conductivity) also increases with R - making it even worse for smaller bodies.

Re:Heat energy. (0)

Anonymous Coward | more than 3 years ago | (#34808676)

It gets its energy from all the extra apostrophes people insist on inserting into innocent possessive pronouns.

Re:Heat energy. (0)

Anonymous Coward | more than 3 years ago | (#34808754)

Accretion energy and radioactive isotopes decaying. Even batholiths in the crust of the Earth take hundreds of thousands of years to solidify when the heat source is removed. Something the size of the Moon takes billions of years to cool.

Re:Heat energy. (2)

Arancaytar (966377) | more than 3 years ago | (#34808864)

Once the outer surface has solidified, it insulates the core quite well. The moon's surface temperature drops to 100K (almost cold enough to liquify oxygen in Earth's atmosphere) in the night, which is pretty cold considering that the sun heats it to 390K (hotter than boiling water) by day. In other words, the surface doesn't get much heat from below. A few billion years might just not be enough for it to cool out completely.

Finding heavy elements (1)

MichaelSmith (789609) | more than 3 years ago | (#34808320)

So if the moon started out with heavy elements like uranium, a lot of them will be in the core now, keeping it warm. The crust is mainly light stuff, silicon, etc, with the occasional lump of meteoric iron.

Re:Finding heavy elements (5, Informative)

AfroTrance (984230) | more than 3 years ago | (#34809868)

Incorrect. Elements segregate in the Earth (and Moon) based on chemical affinities [wikipedia.org] , not on weight. And this is just relative abundance (relative to composition of the solar system). You get all elements in all parts of the Earth, but there is relatively more lithophile elements in the crust, and relatively more siderophile elements in the core.

And uranium is a lithophile, so it is more concentrated in the crust. It still keeps the core warm though. The crust is like an electric blanket, it insulates and provides heat (through radioactivity) to the core (and mantle).

Re:Finding heavy elements (1)

ErikInterlude (784049) | more than 3 years ago | (#34812246)

So what happens if or when we mine enough Uranium from the Earth? Would the drop in radioactive heat allow the core to cool significantly faster, or is it just a redundant heat source? I'm working on the assumption that, even if we did mine out all the Uranium, the core wouldn't cool down fast enough to matter to anyone with an average human life span, but all the same I'm curious just how much of a cooling impact there would be.

Re:Finding heavy elements (2)

AfroTrance (984230) | more than 3 years ago | (#34812422)

To correct/or add to my previous point, most of the heat generated would be from the mantle and core, not the crust. Even though uranium etc are more concentrated in the crust, the much higher volume of the mantle/core negates this. Also, other elements provide heat through radioactivity, such as thorium and potassium-40.

Finally, we can't mine all the uranium. It's only profitable to mine highly concentrated uranium, close to the surface. How concentrated or deep will change in the future as demand increases, but the amount mined relative to everything else will still be insignificant.

Re:Finding heavy elements (1)

AfroTrance (984230) | more than 3 years ago | (#34812478)

Actually, I was reading up on it, and some sources say half of the heat comes from the crust, while others say most comes from the mantle/core.

Re:Finding heavy elements (1)

M8e (1008767) | more than 3 years ago | (#34813770)

The difference between those two statement could be really really small.
One say 50% from the crust. The other says more then 50%(50.01%?) from the mantle/core.

Did anyone of those sources say something more informative than "most"?

Re:Finding heavy elements (1)

drinkypoo (153816) | more than 3 years ago | (#34813580)

Incorrect. Elements segregate in the Earth (and Moon) based on chemical affinities, not on weight.

The mantle is below us and mostly made out of heavy elements, or at least it contains a higher concentration thereof. It's probably safe to say that elements segregate both due to weight and chemical affinities. It's not like uranium is going to jump up off the soil if you hold some rocks over it. This characteristic is more produced in the mantle than the crust, probably due to melting effects.

Re:Finding heavy elements (1)

Will.Woodhull (1038600) | more than 3 years ago | (#34811498)

And somewhere in between the surface and the core is a temperate zone where water is in its liquid phase. Since we have found life in every environment on Earth where water is liquid, we need to assume that there is some kind of thermal driven ecosystem inside the Moon.

Are there selenites? Possibly so. I hope the lunar exogeolists are talking with the biologists who have been studying our black smokers.

Re:Finding heavy elements (3, Interesting)

MichaelSmith (789609) | more than 3 years ago | (#34812390)

Check out the temperature at 2 metres depth [nasa.gov] . I reckon your temperate zone is close enough to the surface that the regolith at that depth will be as dry as it is at the surface (except in cold polar craters).

Conclusion: other than at the pole the moon may be too hot and dry for life as we know it.

And yet, (1)

unity100 (970058) | more than 3 years ago | (#34808352)

it looks artificial like no other thing in the solar system does. so much that that many asteroids hitting over all those aeons only had had created that many impact and changed its landscape only so much. absurdly, its uniform gray dust.

Re:And yet, (4, Interesting)

icebike (68054) | more than 3 years ago | (#34808514)

Looks a lot like other moons, and even like Mercury, and not totally unlike Mars.

Its the only moon in a warn (not hot, not frozen) zone, and its far from uniform.

If it was totally solid you might expect more landscape features created by impact. But because it is simi-fluid and reasonably large, gravitational forces keep super-large scale features from being formed.

Re:And yet, (3, Interesting)

unity100 (970058) | more than 3 years ago | (#34808822)

incorrect. mercury and mars, have varying atmospheric or environmental conditions shaping them. there is a reason why they are that flat, and uniform. there is something grinding the stones to sand.

you have easily accepted the fluidity that was just a new proposition. it is equally interesting that you havent asked why the moon was already that fine grained up till this point. it is as if it was custom ordered to perfectly absorb meteorites, being not too soft, or not too hard, and finely grained. there is no other occasion like that in solar system.

Re:And yet, (0)

Anonymous Coward | more than 3 years ago | (#34809082)

It's also interesting how neither of you seem to have a fully working keyboard.

Re:And yet, (1)

lawnboy5-O (772026) | more than 3 years ago | (#34809208)

Very interesting point when in considering that in proportion to it host planet (huge ration actually!!), its the largest moon in sol, and as thus, having the most influence over its host planet, with the most important force at play with bodies this big - gravity.

Re:And yet, (5, Informative)

BradleyUffner (103496) | more than 3 years ago | (#34810068)

incorrect. mercury and mars, have varying atmospheric or environmental conditions shaping them. there is a reason why they are that flat, and uniform.

Mars is flat?? I don't know where you get that idea from. Mars has mountains and valleys that dwarf anything we have on earth. Olympus Mons is over 21km tall, almost 3 times the height of anything on earth.

Re:And yet, (1)

dkf (304284) | more than 3 years ago | (#34813094)

Mars is flat?? I don't know where you get that idea from. Mars has mountains and valleys that dwarf anything we have on earth. Olympus Mons is over 21km tall, almost 3 times the height of anything on earth.

Maybe he's basing it on some of the pictures that have been sent back (though obviously not the ones of inside a crater) which have mostly been from fairly flat locations as they're easier to land safely in and get good scientific results back from.

relatively (1)

unity100 (970058) | more than 3 years ago | (#34813210)

flat. it has mountains and valleys that dwarf anything here on earth, however it doesnt have huge oceans covering huge depths, or huge mountain ranges that go half a continent, like here. its appalling that you talk about mountains and valleys yet forget huge oceans that have 11,000 m as their deepest point in a hole that covers almost half of the planet on one side, not to mention others in other oceans. its not just a mountain, it is a huge inward landscape on all sides of the planet, and outer protrusion on other. take oceans off of the earth in your mind's eye, then rethink.

Re:And yet, (0)

Anonymous Coward | more than 3 years ago | (#34813436)

Ofcourse Mars has bigger mountains, its smaller than Earth

Re:And yet, (1)

BradleyUffner (103496) | more than 3 years ago | (#34814978)

Ofcourse Mars has bigger mountains, its smaller than Earth

That doesn't doesn't make much sense... Thats like saying "Of course it has taller mountains, it's RED"

Re:And yet, (1)

clintonmonk (1411953) | more than 3 years ago | (#34812472)

it was custom ordered ... being not too soft, or not too hard

Let me guess, the surface is not too hot, but not too cold? ;)

Re:And yet, (2, Insightful)

Anonymous Coward | more than 3 years ago | (#34812610)

Hail to the Great Spaghetti Monster in the Sky, he hath done a greate jobbe!

Re:And yet, (1)

ultranova (717540) | more than 3 years ago | (#34813676)

mercury and mars, have varying atmospheric or environmental conditions shaping them. there is a reason why they are that flat, and uniform. there is something grinding the stones to sand.

The temperature difference between night and day grind moonstones to dust. So do the very meteor collisions you mentioned. And lack of tectonic or volcanic activity means there's no new mountains being rised, so of course the end result is a flat, dust-filled world.

Re:And yet, (1)

unity100 (970058) | more than 3 years ago | (#34814252)

its so easy to justify. thats the problem of contemporary science. very easy to produce half assed explanations for everything.

that half assed one, for example, fails on the face of the fact that there are even greater forces, be it temperature difference, or others, acting on other planets and moons. yet no planet is such finely grained into sand.

Re:And yet, (3, Insightful)

Kenja (541830) | more than 3 years ago | (#34808606)

I know I'm not suposed to engage crazy people. But most things in the solar system look unique, its not that big a place, and there are other grey lumps of rock and dirt here.

Soo... That's no moon...? (1)

denzacar (181829) | more than 3 years ago | (#34808618)

Is that what you are saying?

Re:And yet, (1)

Anonymous Coward | more than 3 years ago | (#34810744)

Fantastic as it is, here is absolute, undeniable proof that humans created the moon: Who built the Moon? [mental-magic.com]

Case closed.

Orale (0)

Anonymous Coward | more than 3 years ago | (#34808384)

Si o que?

A. C. Clarke (1)

Anonymous Coward | more than 3 years ago | (#34808458)

Arthur C. Clarke had a novel where they used the molten moon core as a weapon against spaceships.

Re:A. C. Clarke (1)

MichaelSmith (789609) | more than 3 years ago | (#34808632)

In Earthlight, yeah. I reckon you could build a good city on the moon around a drill to the lunar outer core. Should be possible to recover energy and useful elements from that depth.

Inner Core (0)

Anonymous Coward | more than 3 years ago | (#34808526)

So can we assume the inner core is most likely Parmesan?

Drill baby, Drill! (2)

stealth_finger (1809752) | more than 3 years ago | (#34808532)

What's a cthulhu? fhtagn...wha?

Much more important astronomical news (1)

Anonymous Coward | more than 3 years ago | (#34808854)

There have been discussions of a probe to Uranus [nationalgeographic.com] . Don't the Slashdot editors realize how many more silly jokes and pageviews this could generate? As a stockholder in GKNT, I demand that you post a story about the Uranus probe.

Re:Much more important astronomical news (1)

Anonymous Coward | more than 3 years ago | (#34809734)

Goddamned Frenchmen are always trying to pull this kind of stuff.

The Core (2)

jhobbs (659809) | more than 3 years ago | (#34809300)

So all we have to do is build a drilling thingy, go down to the core and restart its rotation with nukes a la The Core. Presto, livable moon and no more city destroying earthquakes, right?

It's not fluid. (1)

Seumas (6865) | more than 3 years ago | (#34809428)

It's a layer of cheeze whiz!

CHEEZ WHIZ (1)

kernel panic attack (810175) | more than 3 years ago | (#34809674)

for everybody!

Whoa! (1)

martin-boundary (547041) | more than 3 years ago | (#34809902)

First sand traps, and now there's even a liquid outer layer on the moon? Man, that's gotta mess with anybody's golf handicap!

Of course.... (1)

owlnation (858981) | more than 3 years ago | (#34810086)

Of course it's fluid. What do they think the Whalers sail on?

Couldn't they have figured this out long ago? (0)

Anonymous Coward | more than 3 years ago | (#34810324)

All those dark "mare" craters that were apparently volcanic at one point - doesn't this require a molten core?

Re:Couldn't they have figured this out long ago? (1)

fredmosby (545378) | more than 3 years ago | (#34811410)

It requires a core that was molten at one point. The number of impact craters covering those features indicate there hasn't been a volcanic eruption on the moon in a long time.

What was the age of theose Mares then? (1)

G3ckoG33k (647276) | more than 3 years ago | (#34812252)

Yes, I totally agree. It did bother me too. But the general consensus seem to be that they are much older, which is why the are underlying the craters, not the other wat around.

What was the age of those Mares then? IIRC, the general view was that they are so old that they 'froze' around the birth of Jes, err, The Earth.

But, this molten core could mean the mares are much younger, I guess!

Magnetic field (1)

bytesex (112972) | more than 3 years ago | (#34812642)

But then, if the moon really is formed out of stuff from earth (which contains a lot of iron ore), and it *does* have a liquid core (making that iron spin) - then why does it not have a proper magnetic field ? Is its rotation too slow ?

Cheese is a liquid! (0)

Anonymous Coward | more than 3 years ago | (#34813736)

Cheese at warm temperature is a liquid!

Mmm, all that melted cheese.

Nothing to see here. Move on.

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