NO SUCH THING AS GRAVITY

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tulip

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How can such a thing such as gravity exist when it is beyond our senses to preceive it. I see that a ball falls toward earth, but I cannot observe gravity with any of my senses. How can this be scientific if it doesnt rely on our sensual perception/oberservation/testing of reality. The ball may drop at 9.8 m/s^2 but how can this be attributed to a "force"??<br /><br />If this is a valid why isnt the force of "god" valid when we can observe the RESULTS of such a force but not preceive the CAUSE of it with any human senses.
 
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qso1

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I hope I can shed some light on your question, here goes.<br /><br />Tulip:<br />How can such a thing such as gravity exist when it is beyond our senses to preceive it.<br /><br />Me:<br />Its not beyond our sense of sight which by and large is why we are able to percieve it.<br /><br />Tulip:<br />I see that a ball falls toward earth, but I cannot observe gravity with any of my senses.<br /><br />Me:<br />You contradicted yourself in the above statement. Your sense of sight, one of the five known senses, allows you to observe gravities effects.<br /><br />Tulip:<br />How can this be scientific if it doesnt rely on our sensual perception/oberservation/testing of reality.<br /><br />Me:<br />Again, sight allows for the very thing you describe in the paragraph above and gravity has been well tested. It is the primary reason for our understanding of planetary motions etc. Solar/lunar eclipses are predicted to a very high degree of accuracy precisely because we understand gravity, see its effects. We just don't understand what it actually is. Is it wave nature as light is? Is it some kind of force or magnetic type field? We just dont know. If you go through an electronics course, you will find we still don't know the exact nature of electricity. But we know it well enough to harness it.<br /><br />Tulip:<br />The ball may drop at 9.8 m/s^2 but how can this be attributed to a "force"??<br /><br />Me:<br />What else could it be attributed to scientifically speaking?<br /><br />Tulip:<br />If this is a valid why isnt the force of "god" valid when we can observe the RESULTS of such a force but not preceive the CAUSE of it with any human senses.<br /><br />Me:<br />Force of God may well be what gravity is, we simply call it gravity. Science cannot prove there is a God behind it. That is the domain of those who believe. Those of a religious faith which is a whole different aspect than science.<br /><br />The effects of gravity regardless of where it comes from are well documented, mathematically accurate, o <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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vogon13

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{post deleted}<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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doubletruncation

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We can measure the relative masses of objects, and we can also measure distances, speeds and accelerations. In the Newtonian point of view all the law of gravity is saying is that if you take two objects with measured masses (say m1 and m2) and put them a distance r apart from each other, then the first mass will suffer an instaneneous acceleration of Gm2/r^2 and the second mass will accelerate by Gm1/r^2 towards each other. If you put some other forces (a push or a pull) on either of the masses then the net acceleration that the mass feels will be the vector sum of the individual accelerations that the mass would have undergone if each force were applied in isolation. Note that the law of gravity really is indistinguishable from the observations that it predicts - there is no "cause" for it, it's just a synthesis of our observations of how objects move in the presence of other objects and it turns out that the motions are quite regular and describable by this simple rule (there is no a priori reason why this should be the case - you have to do the observations to determine what the rule is). In the general relativity case the rules that we call gravity are slightly different, but again there is no "cause" (you can say space is curved, but at a fundamental level this is just a succint description of the rule that can be used to determine how objects move in the presence of other objects). I don't think there's anything provably *wrong* about saying that God is the cause of gravity, or God is the one moving the objects around. But I think this is different from the physical law of gravity which is just a rule for determining how we will see the objects move (apparently if God is the one pushing the objects around then he is doing so in a way that you would predict using the law of gravity). I would argue that adding God as the prime mover is from a physical point of view irrelevant. Saying that God moves the masses around doesn't affect the predictions for ho <div class="Discussion_UserSignature"> </div>
 
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tulip

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I did not contradict myself. You simply didnt understand my question. I SEE A BALL DROPPING but not gravity as the cause . The cause is me letting go of the damn ball. Get my point?? We do not see gravity. We only see the so called effects of it. Therefore, how can we say that there is a force called gravity that makes the ball drop toward the ground? Perhaps, the ball drops down because purely of weight and not some INVISIBLE FORCE. I still cannot fathom how you can say we can use our sense of "sight" to observe a "FORCE" that is purely invisible if it does exist. We see a ball dropping and that is what we saw before Newton proposed his theory on gravity. He basically imagined up some force that acts on the ball/apple to make it fall to the earth. I say , its purely the weight of the object and the fact that you LET GO of it that causes it to fall down. Not some mythological force that we supposedly have. It has only become the "reality" of our lives because the idea was created first, not the manifestation of what already existed.
 
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vogon13

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We had a poster here last fall that denied the existence of electricity.<br /><br />{I have no idea how he made his post}<br /><br />This is all starting to ring a little familiar, if you catch my drift . . . . . .<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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doubletruncation

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<blockquote><font class="small">In reply to:</font><hr /><p>I SEE A BALL DROPPING but not gravity as the cause<p><hr /></p></p></blockquote><br /><br />I think you may be getting caught up on symantics. As a physical law, gravity is indistinguishable from the observations that it predicts. The reason people talk about a "law of gravity" or "gravity causes things to fall" rather than just listing the observations is that there does seem to be a simplifying rule that you can use to predict motions in different situations.<br /><br />If you were just to list the observations you might have to say when I release an apple to the ground it accelerates at 9.8 m/s^2, if I did this at twice the Earth's radius it would accelerate toward the ground at 2.45 m/s^2. If I threw the apple at 17500 miles per hour it would orbit the Earth. A planet orbits the sun with a period that is proportional to its distance from the sun raised to the 3/2 power etc. etc. etc. However you can simplify all of these many observations to a few easy to remember rules that you can then use to predict what will happen in different situations. <div class="Discussion_UserSignature"> </div>
 
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qso1

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Tulip:<br />I did not contradict myself. You simply didnt understand my question. I SEE A BALL DROPPING but not gravity as the cause . The cause is me letting go of the damn ball. Get my point?? We do not see gravity. We only see the so called effects of it. Therefore, how can we say that there is a force called gravity that makes the ball drop toward the ground? Perhaps, the ball drops down because purely of weight and not some INVISIBLE FORCE.<br /><br />Me:<br />Easy now, think about what you said above...purely weight...what do you think weight is?<br /><br />Tulip:<br />The cause is me letting go of the damn ball. Get my point...<br /><br />Me:<br />Whats holding you to the Earth since the Earth has no hands to hold you or better yet what happens when a spacecraft goes into earth orbit...it falls back to earth due to a force being exerted upon it. The reason it won't hit the ground is that it has enough forward momentum to follow a circular path around earth.<br /><br />Tulip:<br />its purely the weight of the object and the fact that you LET GO of it that causes it to fall down.<br /><br />Me:<br />And again, describe in your words what exactly is weight? And in addition, tell me how astronomers use this weight in their eclipse calculations which have come to pass many times and in fact, I've never known an eclipse to fail to come to pass in modern times.<br /><br />Air is invisible, do you think its really oxygen, nitrogen, etc?<br /><br />Newton, astronomers, etc have done a reasonably good job of convincing me that there is a force, not a mysterious star wars force but one that can at least be partly understood by mathematical calculation, observation, and use of that force. We call it gravity and it does exist. Gravity is what causes objects to weigh something. Your using the term weight from an earthbound observers perspective. Think of it from a solar system perspective. What causes planets to go around the sun? Why do we see, and are able to calculate that the planets do g <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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qso1

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He has since been electrocuted...LOL, couldn't resist that one. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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derekmcd

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<i>I say , its purely the weight of the object and the fact that you LET GO of it that causes it to fall down.</i><br /><br />You holding an object is a physical force acting as resistance against the ball falling. When you let go, "something else" causes that object to fall. If I'm not mistaken, the word "gravity" is derived from a Latin word meaning heavy.<br /><br />Call it whatever term you desire, but something other than you simply letting the ball go is the reason it falls to earth. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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dragon04

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<font color="yellow">I say , its purely the weight of the object and the fact that you LET GO of it that causes it to fall down. </font><br /><br />Let's say your "object" is a bowling ball and that it weighs 600 pounds.<br /><br />Even though you're holding it, it vigorously tries to either pull your arm off, or make you go to the ground with it, or fall to the ground if you let go of it.<br /><br />Now. Take your "mother of all bowling balls" into space, step out of your shuttle, and hold the ball. Curiously, no matter what direction you move the ball, it's no longer trying to pull your arm off. It just hangs out with you. Takes no effort to hold it, but DOES take effort to move it around.<br /><br />So the big question is why in the world it wants to rip your arm off standing in the park, but out in space, it doesn't.<br /><br />I'll tell you why. You're moving, and so is the bowling ball. And not coincidentally, at the same velocity.<br /><br />Standing in the park, you're not moving. But the ball still wants to leave you all freaked out trying to decide whether to stare at your arm on the ground or do something about the arterial blood squirting out of your shoulder joint.<br /><br />That's the proof of some force acting on the ball when you are stationary. It still wants to drop, and you don't. Oddly enough, we call that gravity.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>
 
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brandbll

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If you have to see it in order to believe it, than certainly you can stop "breathing oxygen" whenever you please. <div class="Discussion_UserSignature"> <p><font size="3">You wanna talk some jive? I'll talk some jive. I'll talk some jive like you've never heard!</font></p> </div>
 
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Saiph

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Tulip:<br /><br />The reason a balls acceleration is attributed to a force, is because of the very definition of a force (derived from empirical laws of motion).<br /><br />An object will only change it's state of motion if acted upon by a <i>net</i> outside force. A non-moving object will stay that way, unless a net outside force arises. An object moving at a constant speed and direction will stay that way, unless acted upon by an outside force.<br /><br />A change in motion is acceleration, as it measures a change in speed (and direction).<br /><br />So if we see the ball accelerate, it's motion is changed, and a force must be applied. We do not see a physical cause of the force (no ropes, hands, wind, etc), and so we designate a force that follows the observed behaviors: gravity.<br /><br />more later, gotta run. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"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" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
 
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yevaud

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You cannot "see" air.<br /><br />Yet you breathe.<br /><br />If you cannot see it, I suppose it does not exist. Therefore, you will now suffocate to death. <br /><br />That is, by the way, utilizing your own analogy. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>
 
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vogon13

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I had proposed pressing under stones (and deleted it as too 'tough', but since you broke the ice . . . .) as a potential demonstration. Presumably an IQ increase would accompany the breaking of some bones.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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qso1

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Thats even better than my electrocution line LOL.<br /><br />I noticed Tulip hasn't replied lately. I was hoping he would demonstrate the data which suggests or proves gravity does not exists so I don't have to keep jumping off my chair to see if I can fly. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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Saiph

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okay, I'm back...<br /><br />Anyway, gravity is one of the indirect forces, one's we cannot detect directly. We can only observe it's effects. The <i>law</i> of gravitational forces, f=G*m*M/r^2 is an empirical description of gravity's behavior. Other invisible forces follow other "rules" that we've arrived at through observation (electricity, magnetism, weak and strong forces).<br /><br /><br />To get a better grasp on the reality of these forces, despite our inability to directly percieve them, play with two magnets, you can't argue about the existence of a force between them. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"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" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
 
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qso1

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Hopefully, Tulip will see these posts and maybe reconsider the idea that there is no such thing as gravity or be able to show evidence/prove their idea. I think we've all done our best to explain it. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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7lives

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You all have done a good job of explaining the effects of gravity, but what actually is it? How is this force generated by inert matter/mass. What is its power source? How come it never weakens or runs out of "energy"? It is constant.<br /><br />I know that is an attractive force between matter/mass, but that really is too simplistic and just further only explains its effects, not its source. See above questions. <br /><br />We know how electicity is generated, but yet I don't think we know how gravity is generated.
 
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Saiph

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we don't know the source of gravity, nor any of the other fundamental forces (strong, weak, and electromagnetic).<br /><br />We know how to generate electricity, sure, but we don't know the source of the electric force.<br /><br />The only force we do know a "source" for is magnetism, it's created by moving electric charges and is intimately related to electrical forces....but then we end up at square one again...where's the electrical force come from.<br /><br /><br />One way to answer your energy question is this: These forces don't need energy to operate, as they could be viewed as energy differences in and of themselves. Two objects that are moved apart, against their gravitational attraction, store that energy. When gravity later "acts" upon the released objects, it's this previously stored energy that does the work. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"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" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
 
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siarad

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I can kinda see something in this.<br />If you were way out in space or falling under gravity then I can't think of any sense to measure gravity, indeed why would you even think of it.<br />Similarly there may be other things we don't even think about but which may exist.
 
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doubletruncation

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<font color="yellow">or falling under gravity then I can't think of any sense to measure gravity</font><br /><br />This is the first argument towards Einstein's equivalence principle (that being stationary in a gravitational field is equivalent to being in a uniformly accelerating frame, and that freely falling with gravity is equivalent to being in a non-accelerating reference frame). Which ultimately led to Einstein's view that gravity is a fictitious force, the apparent acceleration due to gravity is not the result of a force but the result of spacetime being curved by matter/energy. <div class="Discussion_UserSignature"> </div>
 
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agnau

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Tulip, do you remember the following story/joke?<br /><br />A professor stands up and tells his class, "Have any of you seen, touched, tasted, smelled, or felt God?"<br /><br />No one raised there hands.<br /><br />The professor concluded, "The I submit there is no God."<br /><br />One student in the back stood and asked, "Have any of you seen, touched, tasted, smelled, or felt the professor's brain?"<br /><br />No one answered so the student said, "I submit the professor has no brain."<br /><br />Just because you can not see the force itself does not mean it is not there. I have read several of the posts and agree, the laws do not depend on God (who set them up in my opinion), but on the equations. Once God programmed gravity and all other forces to work, the program was started and continues to runs. When the program terminates or finds a glitch, I'll let you know.
 
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qso1

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Gravity is one of the few, if not the only thing that I have seen work perfectly in my entire lifetime. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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