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malawi_glenn
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What is over simplified? The General Theory of gravity? Have you studied it at university?
That gravity is caused by the curved space time. Do you actually understand what that means or how that works?malawi_glenn said:What is over simplified? The General Theory of gravity? Have you studied it at university?
malawi_glenn said:I tohugh you could use your logic, since I have two times stated that all mass generates gravity and since the neutrons have mass, they generate gravity. Many people thinks that the role of the neutron in atoms are to generate gravity, that is a very big missconception! (does not the hydrogen atom generate gravity??).
Another missconception is that people tends to separate gravity from space-time curvaturing. Gravity IS curvature in space, generated by mass.
I'm not sure that this is the place for teaching you General Relativity. In short, and as malawi_glenn has mentioned, gravity is the curvature of spacetime-- it is not cause by the curvature of spacetime.W3pcq said:That gravity is caused by the curved space time. Do you actually understand what that means or how that works?
I guess Nerfmonkey is talking about exotic scenarios in which the pressure of the "matter" is negative, like in the case of "dark energy" (whatever that may be). This will give rise to a repulsive gravity term.Nabeshin said:Elaborate. I am mystified.Nerfmonkey said:In some cases gravity can be repulsive instead of attractive. But in every day circumstances you're right.
W3pcq said:One theory about the accelerating universe is that gravity becomes repulsive in some conditions.
cristo said:You mean like the condition I just mentioned?
malawi_glenn said:i. Yes a know a bit how Einsteins field equations work, but I will not be able to study its derivations and so on until I get into grad-school, I am still undergraduate and we have still only got the forumulas and learn how to use them, not to derive them.
ii. The general theory of gravity is called many things, like Einsteins general theory of relativity and so forth.
If you don't have any idea what this is, then I am stunned how you still want to argue with me about what gravity is and how it works. The language of physics is math, therefore one can not understand physics correct by using every day life thinking and non-mathematical reasoning.
iii. I ve seen many people who have the missconception that the neutron is the only source of gravity in atoms.
iv. I have quite good knowledge about the English language, if I say "All mass generates gravity" then I of course mean that neutrons, which has mass, is generating gravity. Then one can use his/hers logic to draw the conclusion that massive objects which are not neutrons also generates gravity.
v. I think its boring that people who aren't students of physics, or working physicists, can judge wheater a person have understand something or not. As cristo said, this is not the appropiate place where to study general theory of gravity (I can give you a study plan and book references if you want to learn it, or recommend a college/university), but we (who are physicists) can answer questions about gravity in a short and quite understandable way (that is of course something subjective).
The main question was "what is the difference between gravity and electro magnetic force"? Then some missconceptions where brougth up (the ones I mentioned earlier), and those I gave short comments on.
W3pcq said:I would like to know more about the link between time and gravity. When an object approaches a gravitational field, it's clock slows right. Why is this? Does this have anything to do with sub atomic spin?
W3pcq said:I didn't ever mean to get into an argument with you. You kept wording a sentence wrong making it mean something that you didn't intend.
malawi_glenn said:Remember that the general theory of gravity is not a quantum theory.
You may want to start a new thread or search for old or just google, there is plenty much written about this topic.
malawi_glenn said:So what is wrong with "All mass generates gravity" ?
W3pcq said:This is an Astrophysics forum not a GR forum. If we can only talk about GR, then maybe it should be moved there?
W3pcq said:You kept saying : "All mass generates gravity, just not the neutron." This statement implies that a neutron doesn't generate any gravity. You should have put the NOT before the JUST, and then it would have been correct.
lzkelley said:Although many if not most hold onto the hope that some time (most likely long from now) all of the fundamental forces will somehow be unified... according to our understanding, gravity and E&M are very different.
For instance, E&M forces don't act on things without charge (i.e. neutral sums of charged particles or neutrinos(?) ).
Similarly, gravity doesn't effect massless particles (i.e. photons).
The details of the differences aren't too important, but another one of the main things, is that gravity is about a billion times weaker than the E&M forces.
Did you reverse those two words? Did you mean 'All mass generates gravity, including the neutron and all other massive particles'?malawi_glenn said:All mass generates gravuty, just not the neutron. [emphasis added]
W3pcq said:Sorry, you should have said it different, you must not know the english language very well. You should have said it like this: All mass generates gravity, NOT just the neutron.
Nabeshin said:Also, gravity is strictly an attractive force, whereas electromagnetism can work to attract or repel.