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New Evidence That the Moon Was Created In a Massive Collision

Soulskill posted about 2 years ago | from the let-there-be-moon dept.

Moon 155

derekmead writes "New evidence that the giant impact hypothesis is correct: A paper published today in Nature shares findings of a chemical analysis of Moon rocks that shows fractional differences between the makeup of the Earth and Moon that most likely were caused by the collision between Earth and a Mars-sized planet around 4.5 billion years ago. Although the two are quite similar, it's been previously shown that Moon rocks lack volatile elements, which suggests they may have evaporated during the incredibly intense heat and pressure created during an impact event. But if the hypothesis that light elements actually evaporated from Moon rocks during their formation is correct, you'd expect to find evidence of elements being layered by mass — heavier elements would condense first, and so on. That process is known as isotopic fractionation — a concept central to carbon dating — and the Washington University team's results suggest they found exactly that (abstract). They compared the blend of zinc isotopes in Moon rocks and Earth samples, and found that the Moon rocks held slightly higher proportions of heavier zinc isotopes. If the Moon was indeed once part of Earth — which has been shown by extensive modeling (PDF) — the difference in the balance of zinc profiles would most likely be explained by lighter zinc isotopes evaporating away following a collision."

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Doesn't anyone think... (0, Troll)

Anonymous Coward | about 2 years ago | (#41686107)

...that the moon is just a little...TOO round for this theory to be accurate. Just LOOK at it. Use your common sense.

How the hell does the moon work, anyway? (1)

Dast (10275) | about 2 years ago | (#41686133)

Yeah, and how the hell does the moon work, anyway? Where did it come from? NOBODY KNOWS! NOBODY KNOWS! We'll never know!

Re:How the hell does the moon work, anyway? (0)

Anonymous Coward | about 2 years ago | (#41686163)

Yeah! And the earth's flat anyway!

Plus it's only 9000 years old so how can this have happened 4.5 billion years ago?!!?



Re:How the hell does the moon work, anyway? (-1)

Anonymous Coward | about 2 years ago | (#41686173)


Guys, did you read this hilarious comment?


Re:How the hell does the moon work, anyway? (4, Funny)

Jason Levine (196982) | about 2 years ago | (#41686413)

Easy. First of all, the Moon is made of green cheese. What most people don't know, though, is that this is a highly stinky form of cheese. So the Earth keeps its distance from the smelly Moon. The Moon landings were all faked except for that one documentary about a man and his dog who went to the moon looking for a grand day out.

Re:How the hell does the moon work, anyway? (1)

PolygamousRanchKid (1290638) | about 2 years ago | (#41686481)

The Moon doesn't work. It's protesting in one of those "Occupy" franchises.

The Moon -- A Ridiculous Liberal Myth (5, Funny)

sconeu (64226) | about 2 years ago | (#41686497)

It amazes me that so many allegedly "educated" people have fallen so quickly and so hard for a fraudulent fabrication of such laughable proportions. The very idea that a gigantic ball of rock happens to orbit our planet, showing itself in neat, four-week cycles -- with the same side facing us all the time -- is ludicrous. Furthermore, it is an insult to common sense and a damnable affront to intellectual honesty and integrity. That people actually believe it is evidence that the liberals have wrested the last vestiges of control of our public school system from decent, God-fearing Americans (as if any further evidence was needed! Daddy's Roommate? God Almighty!)

Documentaries such as Enemy of the State have accurately portrayed the elaborate, byzantine network of surveillance satellites that the liberals have sent into space to spy on law-abiding Americans. Equipped with technology developed by Handgun Control, Inc., these satellites have the ability to detect firearms from hundreds of kilometers up. That's right, neighbors .. the next time you're out in the backyard exercising your Second Amendment rights, the liberals will see it! These satellites are sensitive enough to tell the difference between a Colt .45 and a .38 Special! And when they detect you with a firearm, their computers cross-reference the address to figure out your name, and then an enormous database housed at Berkeley is updated with information about you.

Of course, this all works fine during the day, but what about at night? Even the liberals can't control the rotation of the Earth to prevent nightfall from setting in (only Joshua was able to ask for that particular favor!) That's where the "moon" comes in. Powered by nuclear reactors, the "moon" is nothing more than an enormous balloon, emitting trillions of candlepower of gun-revealing light. Piloted by key members of the liberal community, the "moon" is strategically moved across the country, pointing out those who dare to make use of their God-given rights at night!

Yes, I know this probably sounds paranoid and preposterous, but consider this. Despite what the revisionist historians tell you, there is no mention of the "moon" anywhere in literature or historical documents -- anywhere -- before 1950. That is when it was initially launched. When President Josef Kennedy, at the State of the Union address, proclaimed "We choose to go to the moon", he may as well have said "We choose to go to the weather balloon." The subsequent faking of a "moon" landing on national TV was the first step in a long history of the erosion of our constitutional rights by leftists in this country. No longer can we hide from our government when the sun goes down.

it's nice to see the old ways aren't forgotten (0)

Anonymous Coward | about 2 years ago | (#41686891)

gods bless you good sir!

Re:How the hell does the moon work, anyway? (1)

Anonymous Coward | about 2 years ago | (#41686631)

...that's no moon...

Re:How the hell does the moon work, anyway? (1)

Sulphur (1548251) | about 2 years ago | (#41687121)

...that's no moon...

And it doesn't work.
Challenged, he pulls the trigger.
Fireballs race together and toward the planet.
The planet explodes.
Well I guess I showed you.

Re:How the hell does the moon work, anyway? (5, Funny)

HPHatecraft (2748003) | about 2 years ago | (#41686941)

Romney: well what you have to know is that the Moon is NOT a job creator. The Moon is part of that 47% of the solar system that sponges off of the hard work the other half is doing. The Moon is a worthless satellite.

Some Character Who Is Not Romney: Yes, but isn't the Moon responsible for tides? Without tides, there would be no surfers. Without surfers, there wouldn't be the movie Point Break and that would be tragic. The Moon is also responsible for werewolves. You need a full Moon for werewolves to change And I quote

Even a man who is pure in heart
and says his prayers by night
may become a wolf when the wolfbane blooms
and the autumn moon is bright
and if he doesn't wear his Mormon magic underwear

Were it not for the Moon, then the act of baring our posteriors would simply be called "baring our posteriors" or something equally uncool.

I could site numerous other examples, Mr. Future-President-To-Be-Because-The-Current-President-Was-Coasting-Like-It-Was-The-Month-Of-June-In-His-Senior-Year-So-He-Phoned-In-The-Previous-Debate-And-Dropped-Around-4-Points-In-The-Polls-According-To-Real-Clear-Politics. But I think I have made my point. Check and Mate, sir.

Re:Doesn't anyone think... (1)

bhagwad (1426855) | about 2 years ago | (#41686225)

You know, I bet this observation hasn't occurred to the scientists working on this problem. If they hear it, they'll go "OMG you're right! Why didn't we think of that??"

Re:Doesn't anyone think... (0)

Anonymous Coward | about 2 years ago | (#41686477)

Look, I'll say it one more time: COMMON...SENSE. If that does not take with you, what can I do? If you get on board with being right, you do. If not, you don't. WHy should we try?

Re:Doesn't anyone think... (0)

Anonymous Coward | about 2 years ago | (#41686879)

I hate to be "that guy," but it [] needs saying.

Re:Doesn't anyone think... (3, Informative)

jellomizer (103300) | about 2 years ago | (#41686269)

A mars size rock hits the earth, that would create enough heat to melt the rocks and send them into space as a big liquid ball. Those crazy astronauts that play with their drinks show in microgravity that liquid will prefer to be in a sphere shape. So a chunk of liquid rock the size of the moon over Thousands/Millions of years of slowly cooling down would take the shape of a sphere.

Now the moon isn't a perfect sphere, that is because it is spinning while it was cooling and those other gravitational forces shifting it, and once an awhile getting pounded by some other rocks.

Sorry was that a troll?

Re:Doesn't anyone think... (0)

Anonymous Coward | about 2 years ago | (#41686335)

okay...yes. but its better than posting autopsy photos, no? I was kind of going for satire.

(yes, it really is me the author...i'm embarrassed about the lack of question mark, too.)

Re:Doesn't anyone think... (1)

allcoolnameswheretak (1102727) | about 2 years ago | (#41687111)

Grandparent is rated -1, but actually I've wondered about this myself. Is your explanation really accurate or are you just guessing?
Intuitively I would also suppose that a body that was formed from a collision rather than a cloud of gas would assume an irregular shape. I mean, many asteroids and moons of Jupiter are probably product of colissions and do have an irregular shape.

Re:Doesn't anyone think... (4, Informative)

war4peace (1628283) | about 2 years ago | (#41687457)

I suppose you're a troll as well, but to hell with it, I'll bite.
Any celestial body large enough to have a sizable gravity (I am sure there's a threshold formula somewhere, but CBA to check) will take, in time, a spherical shape because of... GRAVITY! (applause in the background) []

Re:Doesn't anyone think... (1)

aekafan (1690920) | about 2 years ago | (#41686285)

As I am finding in reading quantum theory, common sense is usually wrong

Re:Doesn't anyone think... (5, Insightful)

MightyMartian (840721) | about 2 years ago | (#41687871)

"Common sense is the collection of prejudices acquired by age eighteen."
Albert Einstein

Re:Doesn't anyone think... (0)

Anonymous Coward | about 2 years ago | (#41686411)

Um, that caused by gravity.

Re:Doesn't anyone think... (0)

Anonymous Coward | about 2 years ago | (#41688831)

Flag on the moon? How did it get there?

Waste of time and money (-1)

Anonymous Coward | about 2 years ago | (#41686135)

The NASA mission to return to the moon was cancelled and somehow the powers-that-be think it's wise to fund _this_ research? Typical government, always wasting money.

Re:Waste of time and money (0)

Anonymous Coward | about 2 years ago | (#41686167)

Also the sumerians knew that already...

Re:Waste of time and money (1)

Changa_MC (827317) | about 2 years ago | (#41686567)

Going to the moon again will cost billions. Running a few isotopic scans on rocks, involves a grant of several thousand dollars.
Do you grasp the difference between a thousand dollars and a billion dollars?

Now, the war in Iraq probably cost more than ten trips to the moon, and was a far less productive use of our resources - but that's a very different argument.

Re:Waste of time and money (1)

Anonymous Coward | about 2 years ago | (#41686671)

Do you grasp the difference between a thousand dollars and a billion dollars?

Take it easy with the detail work, man. He's probably a politician.

Re:Waste of time and money (-1)

Anonymous Coward | about 2 years ago | (#41686759)

Look after your pennies and the dollars will take care of themselves - that's what I think.

Sure, the grant for this one study wouldn't cover the costs, but add up all the trivial grants and you start getting somewhere.

Which is what this study gives us: trivia. Fine, now we know a bit more about something that happened billions of years ago. Explain to me how that's more important than future exploration.

Re:Waste of time and money (0)

Anonymous Coward | about 2 years ago | (#41687279)



It was a joke.

You know. Politician. Can't tell the difference between billions and thousands.




Re:Waste of time and money (1)

Githaron (2462596) | about 2 years ago | (#41687493)

Sometimes I wonder if they understand what a trillion dollars is when you consider how much debt the country is in.

Re:Waste of time and money (1)

Rockoon (1252108) | about 2 years ago | (#41686737)

Going to the moon again will cost billions.

The Russians were offering to send you around the moon for a measly $100 million in 2005, and now all these new commercial space ventures are offering the same thing for the same price.

The Moon is a Spaceship.. (0)

Anonymous Coward | about 2 years ago | (#41686147)

I Thought the moon was a spaceship....

Couldn't possbly be true... (-1)

Anonymous Coward | about 2 years ago | (#41686181)

Couldn't possibly be... The universe is only 5000 years old!

Re:Couldn't possbly be true... (2, Funny)

niado (1650369) | about 2 years ago | (#41686319)

I think you mean something more like 6012 years old. []

moon is you (0)

Anonymous Coward | about 2 years ago | (#41686219)

If the moon used to be part of the Earth, then there is no reason to go there again. Earth would have all the same material and it is much easier to work with and none of the expensive and dangerous travel is required.

Re:moon is you (1)

Antipater (2053064) | about 2 years ago | (#41686283)

Yeah. You shouldn't hang out with people from Africa either.

Re:moon is you (1)

crakbone (860662) | about 2 years ago | (#41686295)

Evidently you have never visited some of the mining towns I have. I would rather go to the moon.

logic seems a bit suspect (0)

Anonymous Coward | about 2 years ago | (#41686231)

Is there more to this than "earth rocks and moon rocks are very much alike, and we can explain the differences with this marvelous model, so they must be two parts of the same thing broken apart"?

Because I can use that logic to prove that my baseball bat was once part of George Washington's head.

Re:logic seems a bit suspect (1)

Antipater (2053064) | about 2 years ago | (#41686347)

It's more like "this marvelous model seems pretty cool, but if it were true we'd see this weird thing happening with the moon rocks." "Hey, we see that weird thing!"

It's like finding George Washington's dried blood on your baseball bat. It's possible there are other ways the blood got there, but you probably just whacked the guy.

Old news? (1)

Gothmolly (148874) | about 2 years ago | (#41686291)

Who DOESNT think the moon was caused by a collision, outside of a few Creationists?

Re:Old news? (1)

Laxori666 (748529) | about 2 years ago | (#41686399)

The moon was put there by the invisible pink unicorn, her pinkness be praised! Of course, there is no evidence of her having put the moon there because she is invisible.

Re:Old news? (4, Informative)

Laxori666 (748529) | about 2 years ago | (#41686425)

You insensitive clod! The invisible pink unicorn is a demon implanted into the minds of credulous cretins by the Flying Spaghetti Monster to test our faith! Obviously the FSM, his spaghetiness be praised, was the one who created the moon by spontaneously generating a meatball and applying his large-body creation sauce to it. o one listen to parent - he is a deluded fool.

Re:Old news? (2)

SleazyRidr (1563649) | about 2 years ago | (#41686465)

I figured a meatball must have fallen off while His Great Noodleiness was creating the earth.

Re:Old news? (1)

mrbester (200927) | about 2 years ago | (#41687147)

Ramen to that, brother.

Re:Old news? (0)

Anonymous Coward | about 2 years ago | (#41687557)

And here I thought that the moon and earth where the cut-off, asymmetrical balls of a space giant. Somewhere out there is a giant floating penis.

Re:Old news? (0)

Anonymous Coward | about 2 years ago | (#41686429)

Heretic! We all know that Martin Landau piloted the moon to where it is back in the 70s

Re:Old news? (0)

Anonymous Coward | about 2 years ago | (#41686859)

why do so many of the posts on /. make fun of other people's beliefs? so mature.

Re:Old news? (1)

Sez Zero (586611) | about 2 years ago | (#41686553)

Who DOESNT think the moon was caused by a collision, outside of a few Creationists?

Exactly. We all know it was created by the Divine Light of the Fifth Element as it neutralized the Great Evil.

Re:Old news? (0)

Anonymous Coward | about 2 years ago | (#41686565)

I think it was created from aggregation.

Re:Old news? (5, Interesting)

Kittenman (971447) | about 2 years ago | (#41686969)

Who DOESNT think the moon was caused by a collision, outside of a few Creationists?

Tut. Look back at the past. I used to be a lot more into astronomy than I am now, and back in the 70s/80s, the thought that the moon was caused by a collision was not laughable, but looked at askance. One thought was that if there was a helluva collision, why wasn't the rest of the planet shattered into fragments (much like the poor chaps in the gap between Mars and Jupiter...). I took the "both formed together, dual planet" thesis as the latest there was 'til I read Bill Bryson (god help me...) in his book "A short history of nearly everything", or some such title.

Every theory is blindingly obvious and unquestionable, 'til someone proves it isn't. T. H. Huxley read Darwin's "Origin of Species" and thought it stupid of him (Huxley) not to have thought of it. Same here ..

Velikovsky ... (3, Funny)

Mister Liberty (769145) | about 2 years ago | (#41686313)

With some careful interpretation and text analysis of Velikovsky's
works, we may yet find he predicted this.

Re:Velikovsky ... (2)

jfengel (409917) | about 2 years ago | (#41687727)

Meaning... if we ignore the predictions that were outright wrong, and infer predictions that weren't actually made from text that could just as easily be used to infer opposite conclusions... then we might alter the consensus that he was a complete loon?

Whatever works for ya, I guess.

Obviously (-1)

Anonymous Coward | about 2 years ago | (#41686315)

God sneezed.

When Worlds Collide (2)

PincushionMan (1312913) | about 2 years ago | (#41686329)

I'm guessing this happened before Flash Gordon's time. Who knew that 40's pulp sci-fi was based on facts?

Just out of curiosity (3, Funny)

Anonymous Coward | about 2 years ago | (#41686391)

What did the people who only worked 60 hour weeks in grad school believe?

Re:Just out of curiosity (0)

Anonymous Coward | about 2 years ago | (#41686961)

That they didn't love their subject of study enough.

Size of Earth? (1)

emho24 (2531820) | about 2 years ago | (#41686437)

I wonder what the size of Earth would be if there was no impact event that created the moon. Anyone?

Re:Size of Earth? (0)

SleazyRidr (1563649) | about 2 years ago | (#41686479)

About the size of present earth + present moon, I'd imagine.

Re:Size of Earth? (1)

emho24 (2531820) | about 2 years ago | (#41686511)

I guess that is assuming that 100% of the material was absorbed and none escaped. Anyway, just curious.

Re:Size of Earth? (4, Informative)

SecurityTheatre (2427858) | about 2 years ago | (#41686563)

Considering it took a Mars-sized object to cause the collision event, and that a pretty substantial amount of mass would have been blasted away at escape velocity, I'm not sure the veracity of your math.

Of course, you might be roughly right, but probably not for the reasons I think you're implying...

Re:Size of Earth? (1)

geekoid (135745) | about 2 years ago | (#41686781)

wouldn't it be earth + moon + object striking the earth at the time?

Re:Size of Earth? (1)

Shatrat (855151) | about 2 years ago | (#41686997)

earth + moon + object striking the earth - material ejected at escape velocities from massive explosion

Re:Size of Earth? (1)

harperska (1376103) | about 2 years ago | (#41687053)

As mentioned by SecurityTheatre, it would be (earth + moon + impactor) - (sum of material accelerated to escape velocity by impact)

Re:Size of Earth? (1)

wonkey_monkey (2592601) | about 2 years ago | (#41687025)

- the size of whatever hit us.

Re:Size of Earth? (0)

Anonymous Coward | about 2 years ago | (#41687181)

No. The impact that created the moon required an extra mass between the size of Mars and Earth, depending on the models.


Earth Mass: 5.9x10^24 kg
Moon Mass: 7.4x10^22 kg
E+M System: 5.97x10^24 kg.

Mars Mass: 6.4x10^23 kg

So, the proto-Earth had a mass between 7.4x10^22 kg (if the impactor was Earth-sized) and 5.3x10^24 kg (if the impactor was Mars-sized).

Re:Size of Earth? (1)

Antipater (2053064) | about 2 years ago | (#41686607)

Just look at the volume of the Moon compared to the volume of the Earth. 22 billion cubic kilometers vs. 1083 billion cubic kilometers (about 2%). If you added that volume back and assumed it distributed evenly, the Earth's mean radius would increase by just under 50km.

Note: That's assuming there was no extra debris thrown out or outgassed that didn't end up back on the Moon or Earth in the end. Probably not too valid of an assumption.

Further, I'd suggest... (2, Interesting)

bennomatic (691188) | about 2 years ago | (#41686447)

...that Pangea (the conglomeration of land which drifted apart to become our current continents) might have been the Earth's "exit wound", where the Moon's material separated. For me, this is a hunch, with no basis in scientific fact, so I'm not going to declare its truth or defend it, but I would not be surprised if, in 10 or 20 years, some evidence were to surface supporting this idea.

I remember being a kid and thinking that South America and Africa would fit together like a puzzle, and this was long before I'd ever heard of Pangea. Since that time, it's my understanding that irrefutable evidence--basically, the matching of fault lines and mineral components--has been found to support this. Later, I remember having the idea that the Moon may have been spit out of the Earth as the result of a large collision. My hunch was specious as it was based only on the idea that its orbit is perfectly matched with its rotation speed (aka tidally locked), and I understand that it's possible for that to happen in other ways, but this seemed to me the best bet.

That last idea led to the Pangea idea. Maybe I'll read the freakin' article to see if other people feel the same way.

Re:Further, I'd suggest... (-1)

Anonymous Coward | about 2 years ago | (#41686455)

Are you a friend of Al Gore's by any chance because he mentioned the same anecdote in his "Inconvenient Truth" movie. It's amazing how smart you must have been...

Re:Further, I'd suggest... (3, Informative)

Anonymous Coward | about 2 years ago | (#41686517)

Pangaea, Pangæa, or Pangea (play /pænËdÊ'iËÉ(TM)/ pan-JEE-É(TM);[1]) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, forming about 300 million years ago[2] and beginning to rift around 200 million years ago

The Moon is thought to have formed nearly 4.5 billion years ago, not long after the Earth.

Re:Further, I'd suggest... (1)

PolygamousRanchKid (1290638) | about 2 years ago | (#41686611)

. Later, I remember having the idea that the Moon may have been spit out of the Earth as the result of a large collision.

Yes, you had the idea after you saw the movie about that idea back in the '60s: []

Re:Further, I'd suggest... (0)

Anonymous Coward | about 2 years ago | (#41687433)

Judging by his UID he wasn't alive in the 60's. Judging by yours, you probably think everyone older than 30 was alive in the 60's. ;)

Re:Further, I'd suggest... (0)

Anonymous Coward | about 2 years ago | (#41686785)

Wow! you're so smart!

Re:Further, I'd suggest... (2)

MickLinux (579158) | about 2 years ago | (#41687071)

I don't think that that theory would be justifiable, given the proposed hypothesis of a 4.5-billion year old collision. Pangea is nominally 230 million years old, and there was a ton of plate tectonic movement before then.

That said, I've read the articles referenced, and I don't understand where the introduction gets the idea that this proves the asteroid theory. It looks to me like the same evaporation could occur in the event of a georeactor (which I believe *did* happen, though I also believe that it was triggered by a much smaller-than-Mars sized asteroid hitting at an oblique angle.)

Rather, the research just appears to say that "if there was an impact, it would have shown this fractionalization, and we did find that if what we are seing is fractionalization, it was large-scale, and not (for example) local fountaining fractionalization. Further, it appears that it really is fractionalization."

Which doesn't prove a Mars-sized asteroid. It just says that they can account for the heat of whatever threw the moon out: it's no longer a problem.

It appears to be the journalists who got it wrong, but just in case, I sent one of the WUSTL people an email question, asking whether the conclusion of the journalists is justified. I'd really like to know, because I am greatly interested in lunar formation theories.

Now, for all that, I still actually do believe in a young Moon theory: the hage scatter in the isotopic dating, both on the Moon and on Earth cratons says to me that it had to have been a de Meijer / Van Westrenen georeactor. But unlike them, I do not believe a georeactor collection could go sufficiently supercritical on its own, to force out the moon. Supercritical, yes. But it would relieve its own pressure at far lower energies. The only way I can see for the moon to be ejected, is through a *small* asteroid punching through into the mantle, and suddenly forcing one of a collection of Ca/U bergs in the mantle into the center. That could do it. Once that happened, the shock waves from the blast could force another collection supercritical, as well.

Thing is, if that happens, though, then the neutron flooding is going to throw off all your dating, in a scattered pattern, and everything will appear to be much older. Aiieee! The moon, then, has to be much younger than it appears. But there's another thing: the shattering of the crust will result in the release of Kimiberlite style explosions around the shatter cone (similar to a pullout cone in concrete, or the ring of broken glass around a bullet hole that is in a window). We have all that, in two very distinct rings: one surround the Hudson Bay at 850 miles, in a perfect ring, and the other surrounding Vredefort at 850 miles, in a 2/3 ring (including Australia, India, Brazil). But they only align at the Permian extinction. So, ironically, I think you are right about the Permian.

Moreover, at that same time, the Hudson and Vredefort are right over the New England Plume and the Scotia Plume... and the atlantic cracks from one to the other. Moreover, the later-deposited lava sills around the African Karoo are missing in the area of the Karoo, implying that while the lava could intrude between layers all around, there were no layers in that area... the Kimberlites the go all the way up, and all the way down. The shape of the Karoo, and its location, and its orientation at the Permian extinction, all match the shape, location, and orientation of the Scotia Plate.

So, as far as I can tell, everything points to a pair of georeactors that exploded at 230 ma ago.

Asteroid? Yes. Mars sized? No.

Re:Further, I'd suggest... (1)

jackbird (721605) | about 2 years ago | (#41688731)

Do you have a link to any maps that show what you're describing? All the permian-era pangaea maps I'm finding online don't have nearly enough detail to see any of that. Or is it one of those things where you need a graduate degree or a LOT of free time to grok?

Also, I find myself wishing for the first time that Google Earth had a geologic time slider.

Pangea is cyclic, one of many supercontinents (2)

PeterM from Berkeley (15510) | about 2 years ago | (#41687083)


    My understanding of current geological theory is that Pangea is just the most recent of a cyclic occurrence of supercontinents.

    There have been multiple time periods in Earth's history when most of the land was in one supercontinent, which then split into continents, only to rejoin again. Wikipedia has the cycle at 300M to 500M years.

    Here's the wikipedia article. []

    So, I think your exit would theory contradicts current geological theory.


Re:Further, I'd suggest... (2)

Stormy Dragon (800799) | about 2 years ago | (#41687185)

My hunch was specious as it was based only on the idea that its orbit is perfectly matched with its rotation speed (aka tidally locked)

All satellites will eventually become tidally locked to the body they're orbiting. The larger bodies gravity distorts the satellite so that is elongated toway whatever it is orbitting. If the satellite is rotating faster than it's revolving, this bulge has to move along the surface of the satellite, and this flexing gradually drains momentum, slowing it's rotation rate until the bulge becomes stationary.

For example, the length of a solar day on earth increases roughly .002 seconds each century.

Re:Further, I'd suggest... (2)

mapsjanhere (1130359) | about 2 years ago | (#41687505)

Other than Pangaea not forming until 300 million years ago and the moon impact happening 4.5 billion years ago I don't see any problem with your theory.

Re:Further, I'd suggest... (0)

Anonymous Coward | about 2 years ago | (#41687695)

I'd always assumed pangea was where the earth spit the moon out too.
Which was why the place as such a mess. It was pretty busted up for a single landmass. With faultlines and all that turned into what we have now.

But im not an expert. and i don't really care that much either way.

Re:Further, I'd suggest... (0)

Anonymous Coward | about 2 years ago | (#41687801)

You guys have heard of Velikovsky "worlds in collision", right?

Re:Further, I'd suggest... (1)

MightyMartian (840721) | about 2 years ago | (#41687919)

Sorry to blow your theory away, but Pangea formed 300 million years ago, the moon was formed somewhere around 4 *billion* years before that.

That's mo noon! (0)

Anonymous Coward | about 2 years ago | (#41686555)

It is a pace station

As a skeptic of the 'giant impact hypothesis' (1)

BergZ (1680594) | about 2 years ago | (#41686695)

"If the Moon was indeed once part of Earth — which has been shown by extensive modeling (PDF) — the difference in the balance of zinc profiles would most likely be explained by lighter zinc isotopes evaporating away following a collision."

As a skeptic of the 'giant impact hypothesis' of the Moon's origin:
Collisions between planetary bodies are too complex to model.
I won't believe anything based on computer models unless they simulate the interaction of every single particle in the solar system.
"Garbage in - garbage out."
They obviously just kept tweaking the model until it gave them the result that they wanted.
I have an article from a non-scientific magazine in the 1960's that says the Moon drifted gently into orbit around the Earth.
I need to see a Mars size planet actually collide with an exact duplicate of the Earth and form an identical moon before I'll believe it.
The evidence that the Moon gently drifted into orbit around the Earth is being suppressed from the scientific journals! Fraud! Malpractice! It is all hoax to get lucrative government grant money!

... but seriously, all of the above is sarcasm.
I've posted this as a way to express my frustration with how modeling/simulations and proxy data are treated as "compelling" evidence when we are talking about astronomical science, but modeling/simulations and proxy data are all of a sudden treated as "dubious" when we're talking about climate science.
If you go to any Slashdot article about latest developments in climate science you'll find a bunch of (usually AC) comments that are almost identical to the ones above from climate change "skeptics".

Re:As a skeptic of the 'giant impact hypothesis' (1)

larry bagina (561269) | about 2 years ago | (#41687513)

There's a difference between moon-creation models and climate change models: The moon creation models are used to explain how something exists today whereas the climate change models are used to predict how something will be in the future. And future predictions tend to have a pretty poor track record.

Re:As a skeptic of the 'giant impact hypothesis' (2)

Pembers (250842) | about 2 years ago | (#41687759)

Also, if we're wrong about how the moon was formed, the worst that'll happen is that someone has to rewrite a few astronomy textbooks. If we're wrong about humans making the planet hotter (which I don't believe we are), that means rich people don't need to spend a lot of money reducing the amount of greenhouse gases they dump into the atmosphere. Maybe that's why "giant impact deniers" are rather rarer than climate change deniers...

Re:As a skeptic of the 'giant impact hypothesis' (1)

celle (906675) | about 2 years ago | (#41688657)

" that means rich people don't need to spend a lot of money reducing the amount of greenhouse gases they dump into the atmosphere"

      So it all comes down to a bunch of rich people trying to save some money.

Partially on the subject... (1)

xded (1046894) | about 2 years ago | (#41686767)

A sci-fi author (can't recall who) once wrote in a novel that Earth's crust contains a relatively high percentage of heavier elements because of the Moon. Without Moon's (relatively big, as far as satellites are concerned) gravitational pull, heavier elements would've fallen toward Earth's center leaving only lighter ones to cool down and turn solid on the crust.

Can somebody more knowledgeable on the field comment on the theory? Is there any truth in this? Is this an important factor on making a planet habitable for us? Is this an important factor for forming life (as we know it) on a planet?

Re:Partially on the subject... (1)

Impy the Impiuos Imp (442658) | about 2 years ago | (#41687327)

Probably wouldn't have more than a negligible effect -- after all, you don't lighten noticibly when the moon passes overhead.

The moon can barely manage a tiny slosh when tugging on an entire ocean.

Re:Partially on the subject... (1)

Renevith (1556657) | about 2 years ago | (#41687635)

That doesn't seem too plausible.

The moon is only about 1% of the mass of the earth, so let's start with a baseline estimate that it could change surface gravity by 1%. However, it's pretty far from earth's surface (around 100 times earth's radius), and gravity scales with the square of the distance, so now we're talking a 0.0001% change.

It gets worse, though: because we are in mutual orbit with the moon, we are actually in microgravity (freefall) relative to it. In other words, the moon pulls on you with roughly the same strength as it pulls on the earth, so the total 0.0001% change in gravity mostly cancels out! The only part of it that's left is from you being slightly closer to the moon than the earth is (when the moon is above you) or slightly farther (when it's on the other side of the earth). This difference is what causes the tides, but it's incredibly small relative to the gravitational pull of the earth.

Not to mention that the moon was probably not around when the earth was fully molten, or that the earth *does* have heavier elements (iron) predominantly in the center, or any number of other reasons why this idea doesn't seem likely...

Re:Partially on the subject... (1)

mopomi (696055) | about 2 years ago | (#41687737)

This is incorrect.

First, if the moon and Earth were both tidally locked, this might have some ever-so-tiny effect, but probably not enough to notice. There was a time when the fact that the Moon's center of mass is offset from its center of figure was thought to be due to being tidally locked with to the Earthâ"that has been shown not to be the case and the difference is thought to be due to volcanism and large impacts.

Note that the Earth-Moon's barycenter (center of mass) is located within the interior of the Earth, so whatever long-term, direct gravitational effect the Moon has on Earth's materials, it cannot cause those materials to move into the crust of the Earth.

The Moon orbits the Earth rather than being fully locked to it, so its differential gravitational effects on high- vs. low-mass materials would essentially average out over time (sometimes it would be pulling those high mass materials away from the center of the Earth and sometimes it would be pulling them toward the center of the Earth).

Finally, the fact that the Earth has a moon in a non-circular orbit means that it has the opposite effect from what you describe. Tides on the ocean are the most obvious effect from this non-circular orbit; the oceans are gravitationally pulled toward the moon (slightly lagging its passing). The solid earth experiences the same differential stresses due to the passing of the moon, though the strength of the solid earth greatly decreases the magnitude of its change in shape compared with the change in shape of the ocean. So, the Earth is constantly being flexed as the moon passes by (closer and then further away in its eccentric orbit of the Earth). Imagine (or do the experiment) flexing a paperclip very quickly. It heats up because of internal friction. The same is happening to the Earth. The gravitational energy expressed as tides is being dissipated as heat in the Earth's interior. This means that the Moon is (very, very, very slightly now, but a bit more so in the past) contributing to the melting of the interior of the Earth. Because massive materials (iron, etc.) will eventually sink toward the center of a fluid object, the Moon actually contributed to moving the heavier elements (iron, sulfur that binds to iron, and etc.) to the core, not to the crust as described in your post.

Heavy Metal (1)

FUD fighter (2754911) | about 2 years ago | (#41688861)

Asteroid bombardment, vulcanism, and tectonics are the primary methods by which heavy metals accumulated on the surface. If this theory is correct some core materials could have de-orbited back to the surface as well. Either that or Aliens did it. []

Dumb question here... (0)

Anonymous Coward | about 2 years ago | (#41686839)

But why are all the planets and moons so round? Why do we not see some that are odd shapes (Square, Triangular, etc..)? If the moon is because something collided with the earth, did the Earth look like it had a giant wart on it that broke off?

Re:Dumb question here... (1)

50000BTU_barbecue (588132) | about 2 years ago | (#41687241)

Cubical planets typically have "HPLD" written on them.

Re:Dumb question here... (1)

Stormy Dragon (800799) | about 2 years ago | (#41687317)

Because the started as rotating balls of dust that gradually compacted into solid objects. This causes them to form into roughly spherical objects.

Re:Dumb question here... (2)

JazzHarper (745403) | about 2 years ago | (#41687603)

But why are all the planets and moons so round? Why do we not see some that are odd shapes?

Self-gravity. With sufficient mass and radius, gravitational forces overcome the yield strength of the materials and cause even solid bodies to assume a spherical shape. This occurs at about 300km radius. The surface may still be irregular, but overburden pressure causes rocks at depth to undergo plastic or ductile deformation. For a mathematical derivation, Google "potato radius".

The Moon has a radius of over 1,700 km. Bear in mind, also, that much of it and the Earth would have be molten material after being separated by a collision, so both would have returned to a spherical shape rather quickly.

better headline (1)

v1 (525388) | about 2 years ago | (#41686967)

New Evidence That the Moon Was Created In a Massive Collision

Better I think would be "New information discovered adds support to theory of moon created by massive collision"

The headline made it sound like it was already established fact. And even though it's correct use of the word, I think that calling this new discovery "evidence" contributes to this confusion. (though it is the strongest current theory, and will probably eventually be accepted as fact although not likely ever proven)

Marduke (0)

Anonymous Coward | about 2 years ago | (#41687017)

All these people wondering where the moon came from, and the Sumerians figured it out 6k years ago.

More than one model (2)

hemo_jr (1122113) | about 2 years ago | (#41687259)

There has been a flurry of new models (or significant variations on the old model) suggested recently. They include a smaller than Mars impactor that hit at a higher velocity and a slower impactor that was approximately the same size as the newly formed Earth. Both were inspired by studies that showed that the evection resonance of the Earth-Moon-Sun system would allow for a greater slow down in the rotation of the Earth getting to the contemporary 24 hr day. (see [] et al)

Re:More than one model (1)

Impy the Impiuos Imp (442658) | about 2 years ago | (#41687373)

I still haven't given up on the scientific theory that "and YHWH set the lesser light in the sky to govern the night".

That was just before He gave men nipples and women a shriveled weenie and unsealed ball sac.

Massive collision?? (0)

Anonymous Coward | about 2 years ago | (#41688675)

I thought it was a massive explosion. Make your fucking minds up or I'm switching to creationism.

Moon Rocks are Earth Rocks (0)

Anonymous Coward | about 2 years ago | (#41688809)

The reason that moon rocks chemically test like earth rocks is that they are earth rocks from Antarctica.

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