Wormwood Posted July 31, 2008 Share Posted July 31, 2008 I was having a discussion with someone about religion; I'm not particularly religious, that is to say I do not subscribe to any specific mythos, but I don't completely discount those ideas either. I like to defend the religious side because it is usually the tougher position to defend. Anyway, the age old paradox about an omnipotent god creating an object so big that he himself can not lift it came up and I think I answered it, but I want to make sure my reasoning is sound. I said that yes an omnipotent being could create an object so big that he could not lift it, and still be omnipotent. My reasoning was that once an object reaches a certain mass, it can no longer be lifted because it is generating the gravity that you are attempting to lift against. An object can not be lifted against it's own gravity, thus it is a semantic impossibility. All religious implications aside, is my reasoning correct about mass and gravity? Say God was standing on an object with a mass of M, and created an object with a mass of M^10, the gravity of the second object would over take the gravity of the first item making the action of "lifting" the second item impossible in purely semantic terms right? Link to comment Share on other sites More sharing options...
Sisyphus Posted July 31, 2008 Share Posted July 31, 2008 That's an amusingly literal solution, but I have to disagree with you. "Lifting" is always just separating two massive bodies (insert wonderbra jokes). No matter what two objects you're talking about, each exerts exactly the same gravity on the other. When you stand on the Earth and lift a rock, you're not just moving the rock, you're moving the Earth, too. You are, in fact, exerting the same force on both, but since the Earth is so much bigger than the rock, it moves a much smaller amount, inversely proportional to its size. When you drop it, the rock accelerates towards the Earth, and the Earth accelerates towards the rock. Link to comment Share on other sites More sharing options...
insane_alien Posted July 31, 2008 Share Posted July 31, 2008 well, being omnipotent, god could create an object M^100 then easily lift the M^10 mass while standing on the M^100 object(if god stands of course). Link to comment Share on other sites More sharing options...
iNow Posted July 31, 2008 Share Posted July 31, 2008 Isn't this a bit like asking how strong is the scent from unicorn farts, or how hard to you have hit a leprechaun for him to tell you how to get to his pot of gold at the end of the rainbow? Link to comment Share on other sites More sharing options...
insane_alien Posted July 31, 2008 Share Posted July 31, 2008 yes but it does pose an interesting problem. i think of it as what happens when an irresistable force meets an unmovable object. Link to comment Share on other sites More sharing options...
iNow Posted July 31, 2008 Share Posted July 31, 2008 i think of it as what happens when an irresistable force meets an unmovable object. I think that's about the time when you're no longer doing actual physics. Link to comment Share on other sites More sharing options...
Sayonara Posted July 31, 2008 Share Posted July 31, 2008 i think of it as what happens when an irresistable force meets an unmovable object. There is a very loud noise. Which is appropriate, seeing as it's a conflict of words and not physical bodies. Link to comment Share on other sites More sharing options...
Royston Posted July 31, 2008 Share Posted July 31, 2008 i think of it as what happens when an irresistable force meets an unmovable object. Like me advancing on a clinically obese woman. In any case, this thread doesn't belong in physics. Link to comment Share on other sites More sharing options...
Wormwood Posted July 31, 2008 Author Share Posted July 31, 2008 (edited) Sisyphus: But when you "lift" a rock, you aren't lifting the earth. Also, "Lift" denotes upward and away from the source of gravity...how do you determine up when the object being lifted is exerting more gravitational force? I think the important word here is "lift". well, being omnipotent, god could create an object M^100 then easily lift the M^10 mass while standing on the M^100 object(if god stands of course). Well, the question wasn't can God lift anything, but rather can he create something that he himself can not lift. In a semantic sense I would say yes due to the limitations of words and concepts like "lift" and gravity. At some point you aren't really lifting anymore. To the others: I realize that the mere mention of god or religion is worthy of derision and sarcasm, but my question is actually about the nature of gravity, so please try to resist your knee jerk reaction to make a mockery of the whole thread and still not answer my questions. Edited July 31, 2008 by Wormwood multiple post merged Link to comment Share on other sites More sharing options...
ecoli Posted July 31, 2008 Share Posted July 31, 2008 Sisyphus: But when you "lift" a rock, you aren't lifting the earth. Also, "Lift" denotes upward and away from the source of gravity...how do you determine up when the object being lifted is exerting more gravitational force? I think the important word here is "lift". But you are exerting an equal and opposite force downwards. By lifting a rock up against gravity, you're pushing the earth down as well. Link to comment Share on other sites More sharing options...
Wormwood Posted July 31, 2008 Author Share Posted July 31, 2008 But you are exerting an equal and opposite force downwards. By lifting a rock up against gravity, you're pushing the earth down as well. Ah but the question wasn't "can god create an object so big that he can not push it down, or move it" Besides, if you exert an equal force down, and the object you are lifting is heavier and more massive than the earth, then the earth would move before the object. Anyway, what I am talking about is more like standing on the rock and trying to lift the earth. As mass increases, at some point the gravity of the starting point becomes negligable and the task becomes impossible just because of the nature of gravity and lifting. Anyway, I know this is just some stupid thought exercise, but I was just curious if there was a cheap semantic win hidden in there Link to comment Share on other sites More sharing options...
iNow Posted July 31, 2008 Share Posted July 31, 2008 Well, the question wasn't can God lift anything, but rather can he create something that he himself can not lift. <...> ...my question is actually about the nature of gravity... Sorry. That's not an internally consistent position. You first state that your question is philosophical in nature, and then try to convince in sweet non-sequitur style that it's a physics question. Which is it? Link to comment Share on other sites More sharing options...
Wormwood Posted July 31, 2008 Author Share Posted July 31, 2008 Well obviously it is a hypothetical physics question; sort of a semantic question as well I guess. Well, the question wasn't can God lift anything, but rather can he create something that he himself can not lift. This was the question that sparked the idea and was a supposed paradox...you don't have to give it any consideration beyond that. ...my question is actually about the nature of gravity... My question isn't about the nature of God, but the nature of lifting and gravity. Does that make more sense now? Link to comment Share on other sites More sharing options...
ecoli Posted August 1, 2008 Share Posted August 1, 2008 My question isn't about the nature of God, but the nature of lifting and gravity. Does that make more sense now? no, because the 'paradox' you propose is basically asking can the laws of physics be broken to accommodate a myth created by humans. There really is no answer, sort of like the evolutionary biologists largely ignore creation scientists. Physics doesn't have the capacity to answer the question because the question doesn't make any sense. now if you're asking about a hypothetical situation about a person lifting a mass larger than earth mass off the earth, then we can talk. Link to comment Share on other sites More sharing options...
Wormwood Posted August 1, 2008 Author Share Posted August 1, 2008 What's the difference? Link to comment Share on other sites More sharing options...
Klaynos Posted August 1, 2008 Share Posted August 1, 2008 What's the difference? One has the ability to arbitrarily alter the universe the other does not. Link to comment Share on other sites More sharing options...
doG Posted August 1, 2008 Share Posted August 1, 2008 I said that yes an omnipotent being could create an object so big that he could not lift it, and still be omnipotent. How could an omnipotent God be subject to the laws of nature and still be omnipotent? Link to comment Share on other sites More sharing options...
Wormwood Posted August 1, 2008 Author Share Posted August 1, 2008 One has the ability to arbitrarily alter the universe the other does not. Har harI meant for discussions sake...it's a hypothetical...does it really matter who the person is? ------------------------------------------------ How could an omnipotent God be subject to the laws of nature and still be omnipotent? It isn't god that is limited in this instance, but the laws of physics and our terminology. Forget the being...think about the object...once it reaches a certain mass, "lift" no longer applies. Link to comment Share on other sites More sharing options...
iNow Posted August 1, 2008 Share Posted August 1, 2008 Once it no longer follows the laws of physics, nothing any longer applies. Link to comment Share on other sites More sharing options...
SkepticLance Posted August 1, 2008 Share Posted August 1, 2008 I am agnostic, so for me the question is akin to fantasy. Anyway, the best answer I read was : "Yes, he could, but he would choose not to." Think about it. Link to comment Share on other sites More sharing options...
doG Posted August 1, 2008 Share Posted August 1, 2008 It isn't god that is limited in this instance, but the laws of physics... Didn't the laws of physics supposedly come from the omnipotent God? If he/she/it is truly omnipotent then he/she/it should be able to change those laws. Link to comment Share on other sites More sharing options...
Kyrisch Posted August 1, 2008 Share Posted August 1, 2008 Forget the being...think about the object...once it reaches a certain mass, "lift" no longer applies. Why are you guys so hung up about the God? He's actually asking a physics question that is completely answerable. Yes, once the mass that is being "lifted" is greater than the mass upon which one is standing, the "ground" would move more than the object that is being lifted. The object, however, will move, just not nearly as much as the planet. Because of this, I think as long as the lifted object moves it is considered lifting, and both objects will move (at least infinitessimal amounts) even if one is nearly massless or extremely massive. Link to comment Share on other sites More sharing options...
doG Posted August 1, 2008 Share Posted August 1, 2008 Lifting is a relative term, there really is no lifting, just the act of separating two masses. Link to comment Share on other sites More sharing options...
ParanoiA Posted August 1, 2008 Share Posted August 1, 2008 I don't believe in lifting, so the question is sensless. I'm agnostic about mass, so this entire exercise is tripe. Link to comment Share on other sites More sharing options...
Wormwood Posted August 1, 2008 Author Share Posted August 1, 2008 (edited) Why are you guys so hung up about the God? He's actually asking a physics question that is completely answerable. Yes' date=' once the mass that is being "lifted" is greater than the mass upon which one is standing, the "ground" would move more than the object that is being lifted. The object, however, will move, just not nearly as much as the planet. Because of this, I think as long as the lifted object moves it is considered lifting, and both objects will move (at least infinitessimal amounts) even if one is nearly massless or extremely massive.[/quote'] Yes thank you!!! So is this movement localized or the whole? Say the object being lifted is larger than the earth, if you are pushing on it to lift would the minute movement be localized as in a small area of molecules being pushed on by the surface area of the hands lifting, or would it be the whole object that moves? --------------------------------------------------------- Lifting is a relative term, there really is no lifting, just the act of separating two masses. That's how I was thinking. It isn't really "lifting" beyond a certain point. I really just wanted to show that the "paradox" was stunted because of the terms being used. I think some of you have come to the same conclusion but for different surface reasons. Trying to explain the unlimited using limited terms seems futile. Anyway, thanks to everyone for your responses. --------------------------------------------------------- I don't believe in lifting, so the question is sensless. I'm agnostic about mass, so this entire exercise is tripe. Edited August 1, 2008 by Wormwood Link to comment Share on other sites More sharing options...
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