Gravity

Discussion in 'Physics & Math' started by BrianHarwarespecialist, Jul 29, 2015.

  1. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    This thread is meant to list and compare the different strengths of all the forces, as well as make inferences about why there is incongruencies in relation to gravity.

    Content below taken from this link below.

    http://sciencepark.etacude.com/particle/forces.php





    1. The Strong Force
    This force is responsible for binding of nuclei. It is the dominant one in reactions and decays of most of the fundamental particles. This force is so strong that it binds and stabilize the protons of similar charges within a nucleus. However, it is very short range. No such force will be felt beyond the order of 1 fm (femtometer or 10-15 m).

    2. The Electromagnetic Force
    This is the force which exists between all particles which have an electric charge. For example, electrons (negative charge) bind with nucleus of an atom, due to the presence of protons (positive charge). The force is long range, in principle extending over infinite distance. However, the strength can quickly diminishes due to shielding effect. Many everyday experiences such as friction and air resistance are due to this force. This is also the resistant force that we feel, for example, when pressing our palm against a wall. This is originated from the fact that no two atoms can occupy the same space. However, its strength is about 100 times weaker within the range of 1 fm, where the strong force dominates. But because there is no shielding within the nucleus, the force can be cumulative and can compete with the strong force. Thiscompetitiondetermines the stability structure of nuclei.

    3. The Weak Force This force is responsible for nuclear beta decay and other similar decay processes involving fundamental particles. The range of this force is smaller than 1 fm and is 10-7weaker than the strong force. Nevertheless, it is important in understanding the behavior of fundamental particles.

    4. The Gravitational Force
    This is the force that holds us onto the Earth. It could be important in our daily life, but on the scale of atomic world it is of negligible or no importance at all. Gravitational force is cumulative and extended to infinity. It exists whenever there is matter. Your body is experiencing a gravitaional pull with, say, your computer (or anything close to you or as far away as stars and galaxies) but the effect is so small you will never sense it. However, you can sense the gravitaional pull with the Earth (that is, your weight) due to the cumulative effect of billions of billions of the atoms made up your body with those atoms of the Earth. This means that the larger the body (contain more matter), the stronger the force. But on the scale of individual particles, the force is extremely small, only in the order of 10-38 times that of the strong force.

    You will notice that of all the 4 basic forces two of them can be experienced in our daily life. They are also called the familiar forces which are the electromagnetic and gravitaional forces. Similarly, the strong force and the weak force are called the unfamiliar forces.
     
    Last edited: Jul 29, 2015
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  3. Daecon Kiwi fruit Valued Senior Member

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    Okay.

    And?
     
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  5. paddoboy Valued Senior Member

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    That's what I'm waiting for.

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  7. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    The op stated...

    "This thread is meant to list and compare the different strengths of all the forces, as well as make inferences about why there is incongruencies in relations to gravity."
     
  8. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    Instructions are given on post number four Paddo.

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  9. someguy1 Registered Senior Member

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    I'm definitely no expert. I read somewhere that the reason they think gravity is so weak is that it's leakage from another universe or brane or some such. Of course that's speculative physics, not actual physics. But the extreme weakness of gravity is notable. It's irrelevant till enough matter clumps together to become important.

    It's all very mysterious as to how all this happened. Why is there gravity at all? Or any other forces, for that matter? Even if there was no matter or energy in the universe, where did the laws of physics come from? This is a point even the speculative physicists can't answer.

    It would be interesting if there were no gravity. We'd wear velcro shoes and nobody would worry about their weight. Only their mass.

    Here's the definitive comment I think.

    http://www.gocomics.com/calvinandhobbes/2008/07/14
     
    Last edited: Jul 30, 2015
  10. paddoboy Valued Senior Member

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    The forces are the way they are simply because if they were any different, the Universe and all that is in it, would not be as we know it.
    If the multi universe speculation is true, there are probably billions of universes that rose out of billions of fluctuations in the quantum foam pre BB, all with different aspects of the four forces and all with different aspects of what we see as the universal constants and laws of physics.....Some expanded faster with gravity being even less and matter was not able to condense, others may have recollapsed just at or after the first Planck instant.
    If our Universe was not the way it is, we would not be here to contemplate it.
     
  11. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    Thanks for the reply Paddo am really happy with this information it's confirming my thoughts and visualizations, so far so good. The visualizations in my head predicted the same scenario you just described. Minus the multiverse there is a good reason for this.
     
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  12. Daecon Kiwi fruit Valued Senior Member

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    Even a broken clock is correct twice a day.
     
  13. brucep Valued Senior Member

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    I like to think 'because that's the way it is for this universe'. What's being done associated with physics is to describe the phenomena that is in this universe. It's a fact we wouldn't be here if this universe wasn't exactly as it is. These two answers are pretty good. Similar question to the OP. Without asking why. Answer 17. And 22.
    http://physics.stackexchange.com/qu...n-to-say-gravity-is-the-weakest-of-the-forces
    Make sure you read the comment by Feynman. Dude was the greatest physics orator along with being one of those Giants you like to talk about.
     
    Last edited: Jul 31, 2015
  14. brucep Valued Senior Member

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    I think that would be a prediction derived from string theory. The idea being that the gravitational interaction comes from a brane off the main brane. Subsequently the much weaker interaction. Something like that. LOL. That's the only attempt at why I've seen. I'm pretty satisfied with trying to understand the phenomena that does exist in this universe. Another interesting thing about string theory is the cosmological constant has a lot to do with the way a universe is. For instance all universe without cosmological constant are identical while the value of the cosmological constant becomes very important in determining the vacuua [universe]. Talk about esoteric. The real physics is way more interesting than the best science fiction.
     
    Last edited: Jul 31, 2015
  15. Schmelzer Valued Senior Member

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    Yes, that's stringy nonsense.

    Instead, the weakness of gravity is mathematically quite well understood from the point of view of effective field theory.

    Assume you have some quite complicate theory at some characteristic critical but extremely small distance. But we can, of course, only observe things for very large distances. Which of the terms of this complex small distance theory remain important for large distances? If the difference between small and large distances is big enough, almost nothing remains important, Essentially, only a few very special terms in the equations survive - and these few terms are known as "renormalizable theories". All the other things are non-rernomalizable, and that means that, even if they may be big and important for small distances, their importance decreases with distance, in a much faster way than for renormalizable theories.

    Of course, how much faster depends on the terms too, some decrease much much much faster, some only much faster. But, whatever, in comparison with the renormalizable fields one can forget them.

    But with some exceptions. The interesting exception are fields where simply no renormalizable theory exists. In this case, forces caused by such fields will decrease, but once there is no renormalizable term of the same type, the most important non-renormalizable term may remain observable, even if very weak.

    And this is the example of gravity. For spin 2, there exists no renormalizable theory of gravity. And GR is, among all the non-renormalizable theories of gravity, the one which remains the strongest at large distances - in comparison with other non-renormalizable theories. But much weaker than renormalizable theories.
     
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  16. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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  17. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    The real question that's been ommited is... "why do quantum fluctuations even happen at all?"
     
  18. Dr_Toad It's green! Valued Senior Member

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    Why are you shouting?
     
  19. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    There is a reacurring theme here thats indicating something significant. In my opinion it should be investigated further.

    "Poping in and out of existence"
    Why does this even happen at all? It's seems to me like a perfectly logical consequence...
     
  20. Schmelzer Valued Senior Member

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    Most of what popular science articles write about virtual particles is nonsense.

    The problem is that the formalism for all these computations scattering theory - some particles arriving from infinity meet, interact and fly away again. In this formalism, "particles" are only things which can fly alone far away.

    But this is, of course, not all. For the EM fields, only pure EM radiation can be described as particles - photon - which can fly for themself. The usual stable EM fields around charged particles is not some strange combination of light, but another type of solution of the Maxwell equations. But, of course, these forces have to appear in the scattering theory too - if charged particles scatter, these fields are what gives the scattering effects. And they appear there. And they are, in an IMHO unfortunate choice of description, described as "virtual photons".

    The EM field of such "virtual photons" is as real as that of "real photons".
     
  21. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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    Virtual particles are more important than you may think. And they may actually be the key to explaining it all, giving hints - + of some underlying program (code) existing before time and space itself. A creator writing a program that appears random to temporal observers because of they are viewing from the other side.
     
  22. Schmelzer Valued Senior Member

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    I don't think at all they are unimportant. How one may interpret that the 'EM field of such "virtual photons" is as real as that of "real photons"' as virtual photons being unimportant is beyond me.

    No. The most fundamental theory we have is quantum field theory. The basis of this are the fields. Particles are simply quantum states of these fields, like energy levels in atoms, or phonons in acoustics. If one tries quantum fields on curved spacetime, it becomes obvious that even the definition of what is a particle (and what is a vacuum) depends on the actual state of the gravitational field. So, it seems quite obvious that the fields (which remain to be described by the same field operators, independent of the gravitational field) are more fundmental. And what "exists before space and time itself" will be certainly nothing whose very definition depends on the strength of the gravitational field.
     
  23. BrianHarwarespecialist We shall Ionize!i Registered Senior Member

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