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Simplified theories for gravity?

  1. Mar 16, 2013 #1
    I was wondering, are there any major theories about gravity that actually try to simplify it all? Like, I recently heard that potentially the universe is expanding exponentially. It got me thinking. Couldn't this be translated to what gravity is? I mean, we know that gravity depends on the mass of an object , that it is a force (therefore it accelerates) and that it "bends" everything, including time.

    All of that seems to me like gravity is nothing more than exponential growth. If each particle that makes up a ball for example doubles in size for example, then the entire object becomes larger. Since a larger ball has proportionally less surface than volume, the effects would be stronger.

    With that in mind, if we then imagine 2 spheres in an empty space, and then imagine we would stand on top of one of them and look towards the other, then the change in scales would be unnoticable because we're in the system (and we'd grow too). Rather to us it would like the other sphere is coming towards us instead.
    This again would change the "force" gravity into a movement (in regard to surface points for example), which then according to Einstein creates a new system in which time moves more slowly.

    Of course that's just me thinking, and I don't doubt that this has already come up and been found lacking. Which leads me to my original question. Are there any major theories about gravity that try to explain what it actually is? Not knowing what fields are has been buggering me for years now, and I thought gravity might be a nice start :D


    (PS: comments on my own "example" theory are also welcome of course :) )
  2. jcsd
  3. Mar 16, 2013 #2


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    Look up General Relativity.

    Your scale-change concept has been discussed here before. Doesn't work.

    Before you ask for something to be simplified it would be good if you first got some understanding of it.
  4. Mar 16, 2013 #3
    weird, we covered general relativity (tangentially only though) and our prof made sure to tell use that there were a couple of working theories regarding gravity. And I've read similar things in other threads here. But most of them seem overly complex so I was hoping that perhaps there were a couple "simple" ones that would still work. But I guess you're right, I shouldn't meddle with such things until I know more of the basics.

    Do you perchance remember the name of the thread in which you discussed the scale-concept (I tried searching) or perhaps you remember why it doesn't work?
  5. Mar 16, 2013 #4


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    Reasonable question and I can't recall, nor can I think of what best to use as a search. I do remember for sure that it has been discussed several times, although not specifically regarding gravity as you suggest because that is a rather obviously unworkable theory. If everything were expanding as you suggest, there would be no measurement of ANY expansion.

    The main reason it doesn't work, I think, is that some things scale as the square of distance and some as the cube of distance so scaling bollixes things up (changes the math) in ways that are not observed.
  6. Mar 16, 2013 #5
    I didn't think of the measurement issue, it's a good proof against. I don't quite get the context in which objects would scale differently, but I guess I can google that.
    Anyways, thank you for taking the time to help me!
  7. Mar 17, 2013 #6
    I would try reading 'Secrets of The Universe - Discovering the Universal Laws of Science' by Paul Fleisher, it gives many simplified laws that define our lives and the universe we live in; it also provides experiments that you can perform in the safety of your home without any expenses. Gravity is actually the first chapter, its very interesting I assure you. In case you are interested, here is a picture of the book cover.

    Attached Files:

  8. Mar 17, 2013 #7


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    Where is the surprise in that?
    We have to take what we are given in the Universe and 'simple' models don't always exist. Some things are just hard.
    At one level, Newton states things in a fairly simple way - good enough for most space travel.
  9. Mar 17, 2013 #8


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    The concept behind GR is so amazingly simple and elegant, it will blow you away.
  10. Mar 17, 2013 #9


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    No theory tries to explain what something "actually is". They only explain our ideas of how something works and how to make accurate predictions of real life. It isn't possible to explain what something actually is and be 100% sure that you are correct. How would you know it's not something else that simply looks a certain way, and we just have no means of knowing? However, it is believed that more accurate theories are closer to the "truth" than less accurate ones.
  11. Mar 18, 2013 #10
    If gravity was a scale factor, how do you explain planetary orbits?

    That should convince you that this theory is dead.
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