The Moon is fixed

[minorwork]

its not a bad idea that we have some general knowledge about some queries and some certain things. But based on my experience the more we tend to learn the more we realize how few our knowledge is.

And speaking about going to school or university well know a days it's more like of the same thing learning online. But the advantages about learning online and especially learning alone is that no one can guide you to the learning process. No teacher or professor to correct you from your wrong beliefs.

A living master does have advantages over a dead one. The printed word is better than nothing for the dead master. The online experience with a living teacher is better, but face to face, well, no substitute for that.

Biblical perspective comes from Biblical times. Foolish to think the two are the same as relates to cosmos descriptives.

[kathreeds]

Because it rotates at the same rate as Earth orbits

[morphius]

That's nice and all, but I don't think that this board is a place where that desire has a chance to go much deeper than the answers already given. You are asking about a very specialized field known as planetary physics. I used to know a JPL planetary physicist (physics and astronomy) who posted to several boards, especially creationism v. evolution boards, but I haven't seen him around for several years and he never posted to this board.

Then whom ever gives any answer does not know the whole deal. Only the person who can explain the roots (beginning) of the situation knows the “whole deal.” who is better to answer the question of “what is the best solution for a stomach ache?” an artist? A mechanic? A poet? An inventor? A person who knows how to use the best KEY words in google? Or, perhaps, a doctor? Obviously, he gives the best answer based on his knowledge that are based on the “beginning” (and he may still be wrong). So if someone gives and answer and does not know the beginning, they may know something, but they are not knowledgeable enough. I am glad you admit this though. So taking that in to account, I can see why you may have replied to my post, but that is another story for some other day, maybe.

I must say that I am completely at a loss on this topic. Some people on this board think that I weigh in every topic. But that's not true. I actually only address those fields in which I have acquired some specific knowledge. Planetary physics is not one of those fields.

I guess you never bothered to ask further, IMO. I am just curious by nature (not gay curious, to clarify) and most of the time I am enlighten and surpass (who doesn't), I see things easy... but that is just me.

oh yeah, you have alpha tendencies, so you are the man! (regardless of what the non-alpha believes, get it?) IOW, they look up to you so just be alpha, at least that is based one my understandings about "the beginnings."

I think that you have already received the best answer you are going to get from Angry Citizen. That answer seem logical to me.

The best answer for you, but not me- with all due respect. I was just born with a curious mind. To be honest, I believe that I know more things than you do based on this statement alone. I just want to be in control, don't you? Do you want someone else to tell you what to believe even if you are not satisfied with what you where told? If someone knowledgeable about the stars told you, “there are a billion stars in the universe” I guess you would believe him/her. But I like to go further and ask, “how did you count them?”

For more information, I think that you will have to enroll in some astronomy/physics program in a university. Good idea.

That's just a waste of time. Specially when I am not pursuing anything related to astronomy/physics. If you can enlighten me you can. If you can't (or don't want to bother to), you can't. Simple as that.

[morphius]

I don't know how it was discovered. I can tell you, however, that classical mechanics is what applies to tidal bulging and other effects which cause the phenomenon, not quantum mechanics (I'm assuming that's what you mean by the distinction between the macro and micro world).

The bold statement helps a lot in the understanding proses, so thanks.

Imagine if a football were orbiting the Earth. The football's elongation is analogous to the tidal bulging caused by the Earth's gravitational field. (Side note: This would be much easier if I could just draw the pictures, but alas.) Imagine if the ends of the football WERENT constantly pointed at the Earth. What would happen? Well, the ends would have a torque exerted on them by the uneven gravitational conditions (see my previous post on the inverse square nature of gravitational force). This induces a rotation that is either counter to the innate rotation of the body (if it's spinning too fast for tidal locking to take place) or consonant with it (if it's spinning too slowly). Given sufficient time, tidal locking is an inevitability in all gravitational systems.

I can imagine a football orbiting the earth, but I cannot imagine why would a football be orbiting the earth?... or something football-shaped. IOW, the earth is responsible for the football shaped football?.... if that makes sense.

So what I am really getting at is that, did the earth make something round in to a football shape object? And, why did one side of the “object” get attracted to the earth? (and not the other side?) unless the earth is a magnet and one side of the football has a big chunk of metal.

So what I can understand is that the football first stars it's life by being “round” then when it gets close to the earth, something happens that the football grows ends (like a football duh!) due to the earth's gravitational pull. ok. Then one side gets “locked” for some reason. But I just can't seem to understand from point A to point B. but that is just me.

Wait a minute, so tidal locking depends on how fast the object that becomes “locked” spins? I guess it does... but what made those “objects” spin in the first place? let alone, made them turn fast or slow?

I am just wondering, that is all. Thanks for the input nonetheless. It has helped greatly.

However, you're incorrect that the Milky Way is tidally locked with another system. This betrays a misunderstanding of what I said earlier. The Milky Way is not rotating around another galaxy which is close by. This is a prerequisite for any observed instance of tidal locking. Body A (which we take to be the larger of two masses) much always be in close proximity to body B (which we take to be the smaller of the two). Examples include the Earth/Moon system, the dwarf planet Pluto and its companion Charon, and assuming the existence of Gliese 581g is ever confirmed, it too is likely to be tidally locked. What do these systems have in common? Very, very short orbital radii. In the case of Pluto, it's interesting to note that it is also tidally locked to Charon, just as Charon is tidally locked to Pluto. This is a result of the relative lack of mass inequality in the system.

why would the milky way not be “locked” to something? Is it going around in circles? Is it going straight outwards to infinity?

If it is going around in circles, why would it not be locked to something? If it is going straight outward, i'm guessing it is not locked to something. But that also says a whole lot of things too.

Also, is “close proximity” based on micro or macro? I am just curious. What is “close proximity”? That is all.

One doesn't need an astronomy or physics program to understand this. A mechanics (read: not the guy who fixes your car) class will teach you everything you need to know about torques and gravity wells to understand why the moon and other bodies are tidally locked. (Side note: The term 'gravitational locking' has been bugging me ever since I came into this thread, and I only recently remembered why. The appropriate term is tidal locking.) However, if you give me a couple years, I'll be happy to apply an aerospace engineer's orbital mechanics class to this thread -- although at present I don't see much of a need to.

lol @ “not the guy who fixes you car.” funny to me because I fix my own car, there is nothing hard to replace replaceable parts.

Besides that, I get your main poin. I don't understand the beginning though. that is the "hardest" to understand in my view. the "mechanics class" is a step gained though, again, thanks.

[Angry Citizen]

I can imagine a football orbiting the earth, but I cannot imagine why would a football be orbiting the earth?... or something football-shaped. IOW, the earth is responsible for the football shaped football?.... if that makes sense.

If you have a sphere operating in a field of strong gravity, then the side of the sphere closest to the gravity source is going to experience a greater force of gravity than the back. This stretches the spherical body along the radial axis. It doesn't literally become a football. I was simply using it as an exaggeration to illustrate the effect of tidal bulging.

And, why did one side of the “object” get attracted to the earth? (and not the other side?) unless the earth is a magnet and one side of the football has a big chunk of metal.

Well, that's why proximity is so important. It has to be such that the force of gravity on one side is significantly larger than the force of gravity on the other side (by significantly I mean a few tenths of a percentage point or so). It's all about the ratio.

So what I can understand is that the football first stars it's life by being “round” then when it gets close to the earth, something happens that the football grows ends (like a football duh!) due to the earth's gravitational pull. ok. Then one side gets “locked” for some reason. But I just can't seem to understand from point A to point B. but that is just me.

Okay. Imagine a sphere. We'll call this Body A. Now imagine the force of gravity. Gravity "radiates" from Body A in what could be imagined as an infinite amount of concentric spheres centered at the center of mass of Body A. We'll think of these as lines of force. Orbits are allowed to endure because the motion of the orbit lies directly on one of these lines of force. Body B lies on one of those lines of force, and so its orbit around Body A continues without any energy lost or gained in keeping it in orbit. If it 'cuts' through any line of force, however, work must be done, and this causes a decrease in the energy of the angular momentum (at least in the rotational axis of Body B -- angular momentum is conserved along a different axis).

Now, the interesting thing about gravity (and electromagnetism, for that matter) is that it is a conservative field. When I say conservative, I mean that, so long as Body B's path lies directly on those lines of force, no work must be done to keep it there.

But then we look at what Body B is. It's a sphere. That means that some part of it is affected by gravity more than other parts of it. The mere act of rotation in Body B requires work to be done, simply because it's intersecting those concentric spheres of force that we can think of as radiation from Body A.

But the really awesome thing that makes tidal locking work is that it can either speed up the rotation or slow down the rotation depending on the need. This works because, when Body B becomes tidally locked, it no longer intersects those magical concentric spherical lines of force, and thus no work needs to be done on Body B! Reality constantly strives to prevent work from being done on objects, simply due to the conservation of energy.

To finalize this, tidal locking is what nature does to prevent an object from rotating from the perspective of a central body, because that act of rotation requires energy. The object may still be rotating relative to, say, the sun, but it's not rotating relative to the Earth. Get my drift?

Incidentally, I'd like to apologize for my previous explanation. It wasn't inaccurate, it just wasn't rigorous like the one I've just made for this post. This explanation is what a physicist would tell you. It's based on the concept of conservation of energy, which is what makes the universe tick for all intents and purposes. Physicists like it when they can trace something back to conservation of energy. And I do too.

why would the milky way not be “locked” to something?

There's nothing really big and really close by for it to be locked in.

what made those “objects” spin in the first place?

Just unequal force distributions and such.

Also, is “close proximity” based on micro or macro? I am just curious. What is “close proximity”? That is all.

It's macro. It's just the ratio of the force of gravity on one side to the force of gravity on the other. If that ratio is essentially 1, then tidal locking won't occur for an essentially infinite amount of time.

[gallo]

To be honest, I believe that I know more things than you do based on this statement alone.

That's highly doubtful, especially since I have read some of your other posts. You don't actually seem very knowledgeable about much.

[Jack]

Folks, debates should be impersonal, just debate the topic. No one needs to post character assessments of other members. If you need to, re-read the forum rules on civility.

[do not respond]

[morphius]

If you have a sphere operating in a field of strong gravity, then the side of the sphere closest to the gravity source is going to experience a greater force of gravity than the back. This stretches the spherical body along the radial axis. It doesn't literally become a football. I was simply using it as an exaggeration to illustrate the effect of tidal bulging.

Yes that makes sense (sort of) and I don't expect for you to answer all the answers to my questions. But, they are the missing “links” for me to my complete understanding. Her are some of the questions, A) what is making the “spheres” spin in the first place? (e.g. the moon... my guess would be a pulling force... but if that is true, then our galaxy spins due to a pulling force as well, and if that is true it has a tidal lock too. IOW, if something is not spinning, it has no force, pulling it or not). B) is there really literally a “stretch” that occurs or is that just a figure of speech? I mean, if I spin a ball bearing in the air (defying the laws of gravity) and get a magnet close to that spinning metal ball, it will spin less (experience a magnetic drag force) but also start spinning around the magnet too. Clockwise or counter-clockwise depends on the metal ball bearing direction of spin. At least that adds up in my small brain. I don't have a magnet or ball bearing and an anti-gravity box to test that out.

But does really mean that the metal ball bearing stretches when the magnet places a pulling force upon it? I'm guessing that a soap bubble made mostly of micro metal particles may stretch easily... but a solid ball metal? Now, I understand that even glass can experience “waves” like when a bullet strikes it. Even metal can have a ripple effect if a bullet strikes it too. But the ripples in both cases are not noticeable by the naked eye. So I’m guessing the moon “stretching” is barely noticeable too. The locked side of the moon is just assumed it is stretching. And if it is, how far is the stretch? Also, what if that side has a lump and people base that lump as it being stretching. Since there is no such thing as a perfect circle... just joking.

But I get your point.

Well, that's why proximity is so important. It has to be such that the force of gravity on one side is significantly larger than the force of gravity on the other side (by significantly I mean a few tenths of a percentage point or so). It's all about the ratio.

yes I can picture this. If a spinning metal ball bearing is spinning around a magnet (within the zone of the magnets' magnetic force), the rate of the ball bearing spinning rate will be affected. From my understanding, it will cause a “drag”, IOW, make it spin slower. Because if the spinning ball bearing was to be put to the magnet, it would stop spinning. The magnet would have to have a greater mass and force energy than the ball bearing itself though.

But I get your point.

Okay. Imagine a sphere. We'll call this Body A. Now imagine the force of gravity. Gravity "radiates" from Body A in what could be imagined as an infinite amount of concentric spheres centered at the center of mass of Body A. We'll think of these as lines of force. Orbits are allowed to endure because the motion of the orbit lies directly on one of these lines of force. Body B lies on one of those lines of force, and so its orbit around Body A continues without any energy lost or gained in keeping it in orbit. If it 'cuts' through any line of force, however, work must be done, and this causes a decrease in the energy of the angular momentum (at least in the rotational axis of Body B -- angular momentum is conserved along a different axis).

Now, the interesting thing about gravity (and electromagnetism, for that matter) is that it is a conservative field. When I say conservative, I mean that, so long as Body B's path lies directly on those lines of force, no work must be done to keep it there.

But then we look at what Body B is. It's a sphere. That means that some part of it is affected by gravity more than other parts of it. The mere act of rotation in Body B requires work to be done, simply because it's intersecting those concentric spheres of force that we can think of as radiation from Body A.

But the really awesome thing that makes tidal locking work is that it can either speed up the rotation or slow down the rotation depending on the need. This works because, when Body B becomes tidally locked, it no longer intersects those magical concentric spherical lines of force, and thus no work needs to be done on Body B! Reality constantly strives to prevent work from being done on objects, simply due to the conservation of energy.

To finalize this, tidal locking is what nature does to prevent an object from rotating from the perspective of a central body, because that act of rotation requires energy. The object may still be rotating relative to, say, the sun, but it's not rotating relative to the Earth. Get my drift?

Incidentally, I'd like to apologize for my previous explanation. It wasn't inaccurate, it just wasn't rigorous like the one I've just made for this post. This explanation is what a physicist would tell you. It's based on the concept of conservation of energy, which is what makes the universe tick for all intents and purposes. Physicists like it when they can trace something back to conservation of energy. And I do too.

This is an enlightening explanation for sure. I didn't get all (will re-read) but I did some... one thing that caught my eye the most (may be moot) was ”But the really awesome thing that makes tidal locking work is that it can either speed up the rotation or slow down the rotation depending on the need.” This statement made me picture in my head how something small and going fast (like a bullet) would look like if it was tidal locked to something? I'm guessing the tidal locking is meaning less based on that thought. Since if the stretching due to tidal locking was infinite, a spinning bullet tidal locked to something in this earth would at some point become a straight line and then shoot off the “gravitational pull.” Unless the stretching has a “limit” or something. I apologize, my brain just goes off sometimes.

Ok, so if I drill a hole in the center of a golf ball, and tide a rope through it, then spin the ball fast enough, the side closest to the object spinning the ball is going to “stretch.” That also means that if I spin it fast enough, the golf ball will shatter and break apart. e.g. replacing the golf ball with cookie though. Also, that means that the golf ball is not actually spinning by it's own force. So when it breaks of the tidal locking, something else is giving it a jump start to keep on spinning.

Thanks for the input though. Makes me understand a little better.

There's nothing really big and really close by for it to be locked in.

why does it spin though?

Just unequal force distributions and such.

hmm.... just curious, are all planets rotating in the same direction? If you don't know that's cool. :)

It's macro. It's just the ratio of the force of gravity on one side to the force of gravity on the other. If that ratio is essentially 1, then tidal locking won't occur for an essentially infinite amount of time.

interesting, thanks.

[Angry Citizen]

A) what is making the “spheres” spin in the first place? (e.g. the moon... my guess would be a pulling force... but if that is true, then our galaxy spins due to a pulling force as well, and if that is true it has a tidal lock too. IOW, if something is not spinning, it has no force, pulling it or not).

Well, nothing makes them spin. Newton's First Law states that, in the absence of force, the velocity (and also rotation) of an object remains constant and unchanging. We perceive the moon to spin only because of initial conditions set billions of years ago by the forces that shaped it.

B) is there really literally a “stretch” that occurs or is that just a figure of speech?

Absolutely. It's not particularly large, but it's large enough. Even in the absence of a two-body system, a body rotating about an axis will develop an equatorial bulge. The tidal effect merely amplifies this, since it occurs along the same axis.

I'm guessing that a soap bubble made mostly of micro metal particles may stretch easily... but a solid ball metal?

Yup, it too will stretch. Every single thing that experiences a force will stretch along the axis of force. In a spinning ball's case, that axis of force (due to the centripetal force) is along the radial axis from the central point of rotation, creating a bulge along its equator.

And if it is, how far is the stretch?

Well, to put it in perspective for you, the Earth also has a tidal bulge -- both from the moon and from its own rotation. From what I remember, the Earth's circumference around the equator is about 24,100 miles, whereas the one around the poles is about 24,000 miles. I imagine the Moon's is pretty similar in scope.

This statement made me picture in my head how something small and going fast (like a bullet) would look like if it was tidal locked to something? I'm guessing the tidal locking is meaning less based on that thought. Since if the stretching due to tidal locking was infinite, a spinning bullet tidal locked to something in this earth would at some point become a straight line and then shoot off the “gravitational pull.” Unless the stretching has a “limit” or something. I apologize, my brain just goes off sometimes.

All things would become stretched along the axis of force. To what extent, I simply don't know.

Ok, so if I drill a hole in the center of a golf ball, and tide a rope through it, then spin the ball fast enough, the side closest to the object spinning the ball is going to “stretch.” That also means that if I spin it fast enough, the golf ball will shatter and break apart. e.g. replacing the golf ball with cookie though.

Pretty much, yep.

hmm.... just curious, are all planets rotating in the same direction? If you don't know that's cool.

Venus spins clockwise, while all the other planets spin counterclockwise. Sorta. Uranus is weird -- it spins along the axis of centripetal force from the sun's gravity. In other words, on its side.

[Jack]

Here's a page and image that helped me understand gravity a bit better.

24 Gravity Visualized

[morphius]

Well, nothing makes them spin.

I see many flaws in this statement that I really don't know where to begin. (note: I am debating (sort of cause I am also open minded. Also, I don't now much about anything) so don't take it personal... I am not insulting your “intelligence”)

With that gotten out of the way, how can “nothing makes them spin”? If nothing makes (made?) them spin, I guess nothing makes/made them move either. Also, nothing made them the shape they are shaped today. So they spin on their own due to their own energy? Now, if that would be true, if I was to put a ball bearing inside a vacuumed anti-gravity box, the ball bearing would begin to spin on it's own by it's own “energy”.

Lets say that the moon was born sitting in a swing in the playground. Now, the moon would not swing or move if no force was put upon it. Though this analogy also implies that the moon was born tied to the swing set (obeying the swing sets energy). So any force that will make the moon move or spin it is tied to the laws of the swing set. It can only spin on it axis too but not “freely” (restricted) because the swings base is holding it down. I don't know if I am explaining myself correctly. To try to put it in another way, when you spin freely, you spin on your own will with “your own” energy. Though your free will is restricted. restricted by some other force.

force energy is always passed along.

Newton's First Law states that, in the absence of force, the velocity (and also rotation) of an object remains constant and unchanging. We perceive the moon to spin only because of initial conditions set billions of years ago by the forces that shaped it.

I believe you are not getting the “first law” at all. Because if there is an absence of force, what remains constant is no motion, let alone any spinning.

Imagine trying to put a ball bearing in a center of a anti-gravity box minimizing your energy of placing it there. That would only be possible if you place it using a robotic arm (subtracting your nerve energy of movement passed tot he ball... you cannot hold your hand in the air with out releasing force energy). The micro energy passed to the ball bearing would be minuscule (depending on the design of the robots arm precession too though) but lets assume no energy is passed along to the ball. So the ball bearing would just be floating around not spinning for infinity. Now, if you come along and tap the ball bearing with your finger (passing along some energy force) the ball bearing will move and continue to move (with the absence of another force) for infinity... until some other force made it stop and be still. But for some reason i'm guessing that when something stays stills, they are dead. So nothing is still in the real world. There is always motion a force being passed along or what not.

So even if we perceive our moons motions we can see that we perceive it's motion based on some other force besides the earths. IOW, some other force made the moon spin in the beginning besides the earth's “gravitational pull.”

I can see it crystal clear in my head, I just cannot transfer my thoughts into words that well, if it did not go through, blame it on my inability to direct the right energy from my brain to words.

Absolutely. It's not particularly large, but it's large enough. Even in the absence of a two-body system, a body rotating about an axis will develop an equatorial bulge. The tidal effect merely amplifies this, since it occurs along the same axis.

can you prove this with a physical example? How do we know the moon is “stretching” and so is the “earth” due to the “gravity pull”? Because it seems to me that they “may” stretch due to how fast they spin and not by any pull at all. Tidal locking is beginning to not make sense the more I look into this.

There are many variables to just settle on the theory of “tidal lock” in my view. Yet, if I understand tidal locking, I see it as nothing special at all. Meaning, it does not really explain anything big.

I just had a “enlightening” moment just now. So the stretching is nothing hard to understand, because everything stretches. What is hard to understand is their limit of stretching before they break. Like a rubber band stretches ans so do copper pipes. Everyone knows that a rubber band stretches. A copper pipe stretches too depending on heat and it's tolerance for heat. Etc. IOW, everything stretches.

Now the stretching is based on a force pulling it or rejecting it. It's more complicated than that though, I am just over simplifying cus I can step on a cockroach and skill it, my foot force would stretch it's body flat though. even if the cockroach was not sniping or experiencing a pulling force.

I get the stretching part now. (i think)

Venus spins clockwise, while all the other planets spin counterclockwise. Sorta. Uranus is weird -- it spins along the axis of centripetal force from the sun's gravity. In other words, on its side.

this says a lot of other things but they may be off topic (not that I have not gone off topic in my rambling, but I am acknowledging it so...)

E.g. some other force makes the planets spin, since Uranus seems like it is barely getting “locked” to the sun or maybe “getting” free from the “lock.” that means there at least two laws of force there. IMO.

Thanks for your time.

[morphius]

Here's a page and image that helped me understand gravity a bit better.

actually that does not explain anything at all.... for me that is. For one, gravity seems to come from the center of the earth and not from the bottom. Itwould make more sense if there is a mirror picture of that picture to me. But that also would imply that space is not flat... I mean the north pole has gravity too!!