Origins of the Moons

eagledare · Jul 30, 2006

I would like to know any theories as to the origins of all the moons as they all seem to orbit their planets as ours do-same side to its planet. I have a theory if you would like to look at it on http://www.geocities.com/chrismoolman/index.html

derekmcd · Jul 30, 2006

Tidal locking is a natural occurance of satelites orbiting their host planet. Here's a link for ya: http://en.wikipedia.org/wiki/Tidal_locking As for the origins of our moon? That is still debated, but with the fact that composition of both our moon and Earth are quite similar, kinda rules out any capture theory, IMO. This leaves us with it co-accretion or collision. <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

3488 · Jul 31, 2006

The fact that the moon & the Earth are quite similar in chemical composition does not rule out the capture theory. It means that the moon, formed in the smae part of the solar system as the Earth (as did Mercury, Venus & Mars). The co-accretion theory is more plausible however (the giant impact theory for the formation of the moon IMO is highly unlikely). Most larger moons, with the exception of Triton (which appears to be a Pluto like object captured by Neptune), almost certainly formed in orbit around their host planets. The Galilean Moons of Jupiter, decrease in density as one moves further out (Volcanic Io is the densest moon in the solar system). Our own moon appears to be in second place. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

search · Jul 31, 2006

I am also a newbe in any case welcome aboard I hope it helps. The main paragraph concerning your question is pasted below the web site. http://www.nineplanets.org/luna.html "The asymmetric nature of this gravitational interaction is also responsible for the fact that the Moon rotates synchronously, i.e. it is locked in phase with its orbit so that the same side is always facing toward the Earth. Just as the Earth's rotation is now being slowed by the Moon's influence so in the distant past the Moon's rotation was slowed by the action of the Earth, but in that case the effect was much stronger. When the Moon's rotation rate was slowed to match its orbital period (such that the bulge always faced toward the Earth) there was no longer an off-center torque on the Moon and a stable situation was achieved. The same thing has happened to most of the other satellites in the solar system. Eventually, the Earth's rotation will be slowed to match the Moon's period, too, as is the case with Pluto and Charon."

MeteorWayne · Jul 31, 2006

Just curious, on what basis do you consider the impact theory highly unlikely? It explains the composition of the moon, the angular momentum of the earth-moon system, and recent modeling studies have found it to be a robust and plausible solution. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

Saiph · Jul 31, 2006

right, the problem with the co-accretion or co-formation (then capture) idea is the composition. The moon is lacking in heavy metals compared to the earth. It's composition is almost identical to the earths' crust and upper mantle, but it's density and inner structure indicate a very low iron content. If it co-accreted, or co-formed, there should be similar density profiles and heavy metal content. Another problem with co-formation then capture, is the dynamics of the situation, mainly the disruption earth would cause on such a system, prohibit the formation of other large bodies in the same orbital environment. If such a body would form, it would get shifted away in orbit...and likely collide with earth at a later date. A similar phenomena can be seen with the kirkwood gaps of the asteroid belt and the resonance/disturbance jupiter lends to the system, and they aren't even in the same orbit (merely a resonant one). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

search · Jul 31, 2006

http://www.swri.org/3pubs/ttoday/spring99/moon.htm

eagledare · Jul 31, 2006

A astriod of just the right size, speed and angle to strike earth so hard that a piece flies of into space then not just the once on earth but about 30 times on the other planets too, it is very unlikely.

odysseus145 · Jul 31, 2006

<blockquote>In reply to:<hr />A astriod of just the right size, speed and angle to strike earth so hard that a piece flies of into space then not just the once on earth but about 30 times on the other planets too, it is very unlikely.<hr /></blockquote> No one is suggesting that the way in which Earth's moon formed was anything like the way other moons formed. The moons that formed around the outer planets co-accreted at the same time. I specify the outer planets, because, if you notice, Earth is the only inner planet that has a substantial moon. If your idea was correct than why doesn't Venus, which is often described as Earth's sister, have a moon? <div class="Discussion_UserSignature"> </div>

Saiph · Jul 31, 2006

Oh, I'll agree it's unlikely, but we don't fully understand the situation in primordial star systems. Maybe large roving planetismals are common, in which case the unlikely impact has plenty of "attempts". Sorta like getting 3 heads on a coin toss is unlikely, especially if you only throw three coins. But if you throw a hundred...well, not so bad then (and if anybody's curious, I know that's a sorta screwy analogy). And that's a very nice link search, thanks! <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

3488 · Aug 1, 2006

I can understand the concerns raised by the doubters of the impact theory of the formation of our moon. I understand that the computer simulations had to be modified & altered to fit the scenrario on a number of occassions to make it work (the moon is far too big & massive & the simulations showed very much smaller moons in unstable orbits being the result). Nature is not like that. Nature does not fit computer simulations. Computer simulations need to fit what is observed in Nature. The impact scenario repeatedly failed to acheive this. The giant impact may have happened, not saying it didn't, but it did not create the moon. I still reckon that the moon formed as a fifth terrestrial planet & was captured. The compostion of the moon also does not concern me in this respect. Yes the compostion of the moon, does resemble the Earth's mantle, but probably resemble, Venus's mantle as well, probably Mercury's & Mars's too. Asteroid 4 Vesta also appears to have a similar composition. Where these also created in a giant collision with Earth?? No. A lone survivor, the others (some maybe as large as the Earth) ended up either in the sun, or where thrown out of the solar system to begin their lonely cryogenically cold, dark, vigils orbiting the centre of the Milky Way. I do not see a particularly big problem with Venus not having any moons. The mass of Venus is about 89% that of Earth & is some 30% closer to the Sun. The Hill sphere of Venus is smaller than Earth's because of these two reasons (slightly less mass than Earth & a stronger pull from the Sun). Venus would find it more difficult to keep a moon. It may well have had at least one moon in its youth, but has since lost it. I am sure there are others who may agree. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

search · Aug 1, 2006

According to your theory: "At the time of the Dinosaurs roaming the much smaller earth, the seas were what we now think to have been inland lakes. Then came the birth of the Moon. The earth cracked open in a round ring and the water gushed into the crack and exploded in the very hot mantle and the force of the explosion sent the piece of earth into orbit forming the moon." Sorry but your theory has already a basic flaw: The best age for the Earth (4.54 Ga) is based on old, presumed single-stage leads coupled with the Pb ratios in troilite from iron meteorites, specifically the Canyon Diablo meteorite. In addition, mineral grains (zircon) with U-Pb ages of 4.4 Ga have recently been reported from sedimentary rocks in west-central Australia. The Moon is a more primitive planet than Earth because it has not been disturbed by plate tectonics; thus, some of its more ancient rocks are more plentiful. Only a small number of rocks were returned to Earth by the six Apollo and three Luna missions. These rocks vary greatly in age, a reflection of their different ages of formation and their subsequent histories. The oldest dated moon rocks, however, have ages between 4.4 and 4.5 billion years and provide a minimum age for the formation of our nearest planetary neighbor. Here is a example of the geological time of Earth (being the bottom the moon formation and then the geological times including the Jurassic when Dinos were rulling) and you can see that Dinos come much later in time. Phanerozoic Eon(543 mya to present) -Cenozoic Era (65 mya to today) Quaternary (1.8 mya to today) Holocene (10,000 years to today) Pleistocene (1.8 mya to 10,000 yrs) Tertiary (65 to 1.8 mya) Pliocene (5.3 to 1.8 mya) Miocene (23.8 to 5.3 mya) Oligocene (33.7 to 23.8 mya) Eocene (54.8 to 33.7 mya) Paleocene (65 to 54.8 mya)<</safety_wrapper>

Saiph · Aug 1, 2006

First, attributing actual rarity/probability with how often a model must be worked on is a poor arguement. The system is a bit complicated, and it will take work (and many tries) to get all the details ironed out. One reason it's difficult is we are dealing with one specific situation, possibly one specific collision, and one specific result. The outcomes from the "wrong" models are all possibilities. Earth could have ended up with those moons, if the collision happened that way. A similar situation is ballistics testing, when you want to determine the circumstances for one specific case. You contemplate and model, and try lots of different variations, until you find the one set of circumstances that reproduce the specific case. Now, you could dismiss the impact theory if it's too complicated in general. Say if a straight forward impact couldn't do it, but you needed a high speed retrograde impactor (i.e. head on collision) to do it. The circumstances giving rise to that are hard to come by. But, all we have is an off center, grazing hit from a large planetismal, at a reasonable speed and angle. Now, as far as composition goes: The terrestrial planets do have similar compositions, however they are different enough that you can tell them apart. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

MeteorWayne · Aug 2, 2006

3488: <blockquote>In reply to:<hr />I can understand the concerns raised by the doubters of the impact theory of the formation of our moon. I understand that the computer simulations had to be modified & altered to fit the scenrario on a number of occassions to make it work (the moon is far too big & massive & the simulations showed very much smaller moons in unstable orbits being the result). <hr /></blockquote> 3488, actually the models developed within the last year are quite robust in explaining the size of the moon and creating a stable orbit. What you say was true perhaps 5 years ago, but science moves onward (at a rapid pace! <img src="/images/icons/smile.gif" /> ) Also, those models refer to the earth-moon system, not the giant planets with their many small moons. They appear to be a mix of co-accretion and capture. The only other comparable system in size ratio is Pluto-Charon, another case where an impact scenario is likely. (Nix and Hydra add credence to that, since they orbit in the same plane and with Pluto's limited gravity capture at that distance is unlikely.) MW <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

odysseus145 · Aug 2, 2006

Coincidentally, badastronomy.com is hosting a video on the homepage depicting a 100-mile impacting the Earth. It's startling realistic. <div class="Discussion_UserSignature"> </div>

eagledare · Aug 2, 2006

A 100 mile meteor?

eagledare · Aug 2, 2006

Thank you for that link derekmcd I had a look at it but it does not make sense. Sure they have all the matematical solutions but the amount of force (kinectic energy) to lift the sand is replaced when the sand goes down again so it cancels out and the gravity force to slow an turning moon down is cancelled out. if it was so the earth would be facing the sun with one side aswell. If you take Mercury closer to the Sun, at a point were it was formed, it will face the Sun with the same side. Its rotational speed does not alter it just moves futher from the Sun as it grows. So do the Earth and all the planets. Think Earths orbit is getting longer by 50 meters every year.

eagledare · Aug 2, 2006

I thought my theory was original until minutes ago when ifound this site. http://www.wincom.net/earthexp/n/moon.htm Have a look at it. a pic from that site with earth fully deflated so that all the continents are together this piece is missing.

search · Aug 2, 2006

Eagledare I took a look at it. If there is an object in the sky which must be rich in theories its the moon. After all its the closest and most observed since the cradle of mankind so let the theories roll and it does not matter how absurde they may be because in the molding pot of inventiveness lies the thruth we all search. You dare to explain what no one is sure about. Be proud. But like all theories they only last until they can be proven wrong and even then the proof can be refuted. Below are some of the mainstreem theories imported from a website lost somewhere in cyberspace: "Prior to the Apollo missions there were three main theories on the origin of the Moon. CAPTURE THEORY A passing body, such as an asteroid or small planet strayed too close and was caught in the Earth's gravitational field. However, if this were the case the Moon's orbit would be an elongated ellipse and not nearly circular as it is. FISSION HYPOTHESIS Sir George Darwin, (1845 - 1912), second son of Charles, proposed that when the Earth was young and molten it span so rapidly that material was ejected. This material coagulated and formed the Moon. The "scar" left on the Earth was thought to be the Pacific basin. However, it is now known that Moon rock and Earth rock samples differ; that plate tectonics are the cause of the Pacific basin and that this explanation is mathematically impossible. BINARY ACCRETION The Earth and the Moon formed alongside each other in the Solar Nebula, the original gas cloud that evolved to be our Solar System. However, although samples of the two bodies share the same elements, the proportions of are different. The ages of the rocks also differ. Since the Apollo missions it is generally agreed that the Moon was formed during an impact. IMPACT THEORY This theory, which was put forward by W.Hartmann & D.R. Davis in 1974, sta

search · Aug 2, 2006

Needless to say that this is a very superficial view of the moon theories and the refuting points is some of them even more superficial but just to point out what theories are up to once they come out.

eagledare · Aug 3, 2006

Search look at the age of the ocean beds and you will see here was hardly any of the present day oceans then (Jurassic). Here is the link to ocean floor dating. http://lupus.gsfc.nasa.gov/plots/maps/jpg/ and have a look at the moon Marinda GROWING http://www.solarviews.com/cap/index/miranda1.html

eagledare · Aug 14, 2006

Thank you Search as we said theories are only theories and how do we prove anything. Up to now maths is used in most theories, if you could come out with an equation that explains the theory it is accepted. Like the one that explains why the moons are facing the same side to their planets is due to slowing down of their rotation by gravitational forces. I am continuing my search and even found an very old map of the smaller earth with a missing piece on it called moon land.

MeteorWayne · Aug 14, 2006

That seems unlikely. An impact large enough to create the moon (as theorized) would have melted the earth in the process, leaving no solid materials to create a missing "moon land". <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

eagledare · Aug 14, 2006

Wayne i do not support the impact theory at all I believe the moons are born from their planets ( a natural birth) that is why we have an ocean at the moment which will be used in the process of the birth of our 2nd moon and i believe it is going to happen within the next 20 years. have a look at my website or an attempted website. http://www.geocities.com/chrismoolman/index.html I tried to just briefly give an overall idea of the procces but is busy at the moment with a more detailed site to bring in all the relevant proof.

MeteorWayne · Aug 14, 2006

OK, I've looked at your website, and, well, you appear not to let facts get in your way so have fun. Expanding planet is a thread around here somewhere, feel free to jump in there. Note the Earth's moon was formed by a much different process than all the moons of the solar system except for Pluto's binary planet (with two extra tiny moons as part of the same process.) If you include the earth's moon creation in the same category as all the others, you are deluding yourself. IMHO <img src="/images/icons/crazy.gif" /> MW <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

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