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Earth May Once Have Had Two Moons
AaronW writes "According to a story at space.com, Earth may once have had two moons. The smaller moon, estimated to be 750 miles (1200km) wide and only 4% of the mass of the larger moon, crashed into the far side of the larger moon which caused the features we see today on the moon. The surface of the far side of the moon is quite different than the side facing the earth, having a different composition and a much rougher terrain."
I plead ignorance on the topic, but this explanation strikes me as a little far-fetched considering that it seems more reasonable to me to conclude that the far side of the moon being so different might more reasonably have something to do with the fact that it's permanently facing away from earth. Wouldn't the far side get somewhat more meteor impacts and somewhat more exposure to cosmic radiation, for example? It would seem to me that the earth-facing side would be at least somewhat shielded by earth, compared to the far side--and that over a very long period of time this could make for a difference in geology. For that matter, wouldn't the gravitational field of the earth also have some effect on lunar geology over extremely long periods of time (effecting the two sides somewhat differently), much as the lunar field effects earth's oceans in the very short term?
Perhaps someone more familiar with lunar geology than your humble narrator could explain why these differences are thought to be unrelated to its orientation to earth, and need to be explained instead by a hypothesis as radical as a moon impact.
SJW: Someone who has run out of real oppression, and has to fake it.
Serious guys. You learn read book now. Thanksbye.
That's no moon...
"Earth Two Moons Once May Have Had" ....
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?"
Next time, take better care of your natural satellites.
org.slashdot.post.SignatureNotFoundException: ewg
Details are still sketchy at this point. Reports that the second moon was inhabited by a super-intelligent race using crystals to seal away an ancient evil, and was accessible from Earth via a "Big Whale," could not be substantiated.
These folks include my Christian, Jewish and Muslim friends, whose religions revolve around the dis-ambiguity that mother earth has always had one moon and not two...otherwise which moon would my friends' holy books be referring to?
but what have now?
can earth has more?
Good people go to bed earlier.
The earth once had thousands of moons, if the theory of how it coalesced from space dust is correct, right?
At one point, the earth would have been nothing but moons, if you think about it.
At what point does it stop being "rotating cloud of rocky debris", and become "planet, with moooooooons"
Ungh, ones NUFF man!! Nuh UNGH!!
"Stratigraphically the origin of agriculture and thermonuclear destruction will appear essentially simultaneous" -- Lee
I once had 2 moons in my pants...
"It is entirely plausible for a Trojan moon to have formed in the giant impact, and for it to go unstable after 10 million to 100 million years and leave its imprint on the moon," study coauthor Erik Asphaug, a planetary scientist at the University of California, Santa Cruz, told SPACE.com. Imagine "a ball of Gruyere colliding into a ball of cheddar."
shudder
Did it have a shadow of a jumping mouse on?
There is no Dark Side of the Moon really, matter of fact its all dark.
Beast wars taught me the other moon was a superweapon that got exploded up.
http://www.youtube.com/watch?v=TQ3flFpD19M&feature=player_detailpage#t=285s
...it was a space station.
I don't think you can use the observable earth as an indication of the protection offered. I would expect that the earth's "gravity well" (sorry, a more proper term escapes me at the moment) would be more relevant. That said I am quite suspicious of your overall approach. It seems to be commonly accepted that Jupiter provides the earth with significant protection, now consider the percentage of the sky hemisphere that jupiter occupies.
It's a known fact that the real far side of the moon is just a Hollywood-caliber set that was created on some government base. Why? Because the real far side of the moon contains a Jetsons-like society of humans who have no concept of a debt ceiling.
You don't need to look to something so esoteric to find missing facts in sacred texts. For example, I don't recall much about micro-organisms in the various bits I've read; however there is a fair amount about various hygienic practices.
Is there really any need to nit-pick at peoples beliefs? Nobody's beliefs are literally right anyways.
No. The second Moon was the home to the Lunarians. The Lunarians are a race of beings from a world destroyed which became the asteroid belt, and are identified by a moon-shape crest on their foreheads. They created this artificial moon, resting until a time they believe their kind can co-exist with humans. But the whole second moon thing got screwed up for everyone, because after Cecil whooped Zeromus' ass, the Lunarians decided to throw that moon into gear and get the hell away from us.
Thanks for nothing, Lunarians.
"I hope you know how very lucky you are to know me, because I am so incredibly incredible."
Seems that we regularly 'discover' that Uranus has another moon or two every now and then. http://en.wikipedia.org/wiki/Moons_of_Uranus I think we know who the culprit is. I would advise you to be a bit more responsible for what Uranus does. Don't think we haven't noticed. Bathing might help.
Sadly, it was destroyed during an accidental "mooning" maneuver the Earth was trying to direct at Venus over some perceived sleight from the previous drunken weekend at the Solar System Club*.
*Membership required.
Who did what now?
I've seen it. It's rubbish.
I read the article, but could not find any mention of observations or physical evidence which supports this hypothesis better than, or even as well as, any generally accepted theory. The article only seems to describe a simulation that the authors cooked up. It would seem that such a collision would have some significant residual effects on the orbit of the moon. I could not find any mention of the time period in which this hypothetical collision occurred. Would there be any geological evidence for it on the earth? Perhaps the space.com article is poorly written but, on the face of it, this theory doesn't seem to have anything going for it.
We sold it to the people of Kababa
http://danbern.redacorn.net/lyrics/twomoons.html
I would put myself in the camp of Christians who would be called evangelical. No problem with this whatsoever.
Except for the Young Earth Creationists, no one would have a problem with this. And they wouldn't have a problem with their once being two moons, but with the timeframes involved.
I still cling to the "Moon is made of cheese" theory, though the thought of two moons colliding does seem intriguing, especially if one was made of Colby and the other Monterey-Jack.
Sometimes the light at the end of the tunnel is the headlight of an oncoming train.
I always knew there was something special about the Dark Side of the Moon. "There is no dark side of the moon really. Matter of fact it's all dark." Queue the "get off my lawn dirty hippie" remarks.
"We are just a war away from Amerikastan. When god vs god the undoing of man." Dave Mustaine
Nope...
And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also.
But Stephen Fry had told us that there are two moons right now! The Moon and Cruithne... of course in a later episode he claimed there's 4 or 5...
________
Entranced by anime since late summer 2001 and loving it ^_^
And one of them had the face...of Jackie Gleason!
I've seen pictures.
You are welcome on my lawn.
EVIDENCE suggests that the remaining celestial body presently orbitting around Planet Earth is actually the 2nd Moon that failed it's half of a mitotic division. The other living half to the Moon became known as the Sun, both were conceived from middle-Earth after the Rock expanded to migrate the Continents to Speciate man into diversity upon the Canopy of Yggdrasil. The Moon in it's present form was itself hallowed into a Space Station by an alien race of supreme beings to cause the increase menstrual cycles of all Earth life to evolve them at expense of lifespan and cultural values. All the so-called Moon rocks exhibitted by NASA are actually foreign impacts and general debris from other orbits and NASA couldn't mine anything from the Moon itself without actual penetrations tools, but they had enough time to play an important game ofminiature golf.
I'm not making this up, not trolling, and my sources are referencable anywhere from Mary Sutherland (http://BurlingtonNews.net) and L A Marzulli (http://lamarzulli.net).
A number of explanations have been proposed for the far side's highlands, including one suggesting that gravitational forces were the culprits rather than an impact from Francis Nimmo at the University of California, Santa Cruz, and his colleagues.
Maybe I'm reading this wrong, but are they suggesting that Francis Nimmo and his colleagues hit the moon?
Damn. That Francis Nimmo is so fat...
They could've just asked me. I was there when the second moon left, after all!
Isn't Cruithne our 2nd moon?
Such a collision lends itself to catastrophism, a theory of large changes that happen relatively frequently.
This would have serious consequences for the evolution of life on the surface.
Nothing would be more disasterous for prelife than a 750 mile wide object impacting the surface of the moon, which at that point in time would be less than 30KM from the earth. The impact would have created impactors almost certainly miles in size that would be ejected into the local gravitational well around the earth.
For perhaps 100,000 years the surface of the earth would be periodically bombarded by objects miles in size from the local orbital well of the moon and the earth.
That would make life constrained to even even _shorter_ time period to evolve life.
-Hack
Got Geometrodynamics? Awe, too hard to figure out? Too bad.
That's no moon...
Because the bloody IAU reclassified it as a dwarf moon or "Lunaoid".
Calling someone a "hater" only means you can not rationally rebut their argument.
Well, obviously the far side of the moon didn't have to be finished off. No one was going to see it.
I am anarch of all I survey.
... you saw the hole in the moon.
Free, as in your money being freed from the confines of your account.
I have the idea that the moon causes tides by NOT PULLING the water upward as hypothesized rather that the moon pulls the air or atmosphere upward and the water rises to fill the lesser area of atmospheric pressure. What about that???
I am not a lunar scientist, but if we're talking about a slow-moving collision with another orbiting body coming from either L4 or L5, wouldn't that have been a collision with the leading or trailing sides of the moon?
It seems...particular...that one of these impacts would have occurred and would have *just* put enough spin on the moon that the moon turned this side away from earth, and then stopped?
Or are they asserting that this body was so low-density that whatever layer it accreted onto the moon then introduced a dishomogenous bias in the moon's density, and earth's gravity then turned the moon 'heavy-side' toward the earth? I'm not sure that's how it would work, mechanically....do satellites turn their 'heavy end' toward earth?
-Styopa
And at one point atlantis rose from the earth, taking with it all the humans, to another planet.....leaving behind that big crater in the bottom of the atlantic....
but I guess this too, we will never really know or be able to prove
One of the problems with moon-related theories is that there really is hardly any evidence left for us to go on. There's a prevailing theory that a mars-sized planet struck earth, and the rebound caused a the moon to glob off. How do we know this is, well, plausible? First, some reasonable assumptions are made about the pre-moon earth, then a computer simulation is run that applies the theory, and then the final results of the simulation are compared to the present time. The prevailing moon theory is therefore the best explanation we have come up with so far. However, scientists rightfully call this a "default" theory, because although it makes a reasonable model, no one believes it's necessarily TRUE. No one is attached to it. Its basically just the only thing we have, so we use it. As soon as someone comes along with some more evidence and/or a better explanation, the old theory will be dropped like a bag of rocks.
As precarious as moon theory is, it's a fantastic example of how science should be. No one should be attached to any theories, and every theory should be treated as if it could be overturned at any instant. Many theories are much more solidly grounded, making them very much more likely to be true. And most theories are really made up lots and lots of small theories (like evolution, which is not any single theory but a whole collection of connected theories).
Am I making a criticism of science? No. Of scientists. Many scientists get too attached to their "life's work" and therefore turn from scientists into evangelists. Fortunately, in many fields there are lots of competing scientists who are very attached to incompatible theories, so it tends to balance out. (This sort of balancing out of competing corruption happens in politics sometimes too.)
The side of the moon closest to us went under continual changes and gravitational forces, it looks different from the back because of these forces. http://www.straightdope.com/columns/read/429/why-does-the-same-side-of-the-moon-always-face-the-earth
Being a smaller planetary body the heaviest elements were pulled toward the earth during the formation of the moon. That imbalance of elements eventually acted as a brake, causing the moon to stop rotating (fully) on it's axis.