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Do chemical properties have an effect on gravitational forces?

  1. Aug 5, 2011 #1
    Do gravitational forces discriminate against chemical energy potential? Could the gravitational forces of three substances, equal in density, but differing in chemical properties affect each other differently based on their differences in chemical energy potential?

    Take two separate bodies of the same substance at equal mass but with different entropy states (or different temperatures) gravitationally interact with a third body any different than the other identical substance?
     
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  3. Aug 5, 2011 #2

    Drakkith

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    Staff: Mentor

    All energy and mass has gravity. I believe an object at a higher temperature than another object is more massive and has more gravity.
     
  4. Aug 6, 2011 #3
    Gravitational field strength is just dependent on the mass of the object. The chemical energy does not matter.

    Energy does not have a gravitational field.

    For objects that are heated, while the interparticle distance is increased, does not affect the mass of the object but just the volume (and hence the density). So there is also no change in the gravitational field strength produced by the heated mass.
     
  5. Aug 6, 2011 #4

    Drakkith

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    Staff: Mentor

    I don't believe that is correct. A hot object will cool over time and lose mass as a result. Less mass = less gravity.
     
  6. Aug 6, 2011 #5
    Perhap you would like to say where the increase and decrease in mass arises from?
     
  7. Aug 6, 2011 #6
    Then why does one O16 atom have a smaller mass then 8 deuterium atoms?
    15.999 vs 16.12
    It's the same number of protons and neutrons. The only difference is the binding energy.
    With chemical binding energy the same effect happens, it's just much smaller.
    The same goes for thermal or any other form of energy. In fact matter only has mass because it is a form of energy.
    So yes, energy has mass. Only energy has mass.
    Someone might claim that light is a form of energy and it has no mass.
    Light has no rest mass, because it can never be at rest. But it does possess gravity.
    Take a box that consists out of perfect mirrors and put some light inside. The mass of the box will increase due to the presence of the light inside.
     
    Last edited: Aug 6, 2011
  8. Aug 6, 2011 #7
    Greetings:
    In regard to gravity and chemistry one should search:
    Chirality and Gravity
    Chiral Eotvos Experiment
    Gravity Chiral Koyzrev.....cheap interesting gravity modifying experiments
    Electrostatic Gravity Gupta

    RJK , Chiralex
     
  9. Aug 6, 2011 #8
    Agreed, but that's just because when you break apart an oxygen atom, the particles fly apart. Measure the moving products in your rest frame and you'll find that the total rest mass before and after is the same.

    As you said, light has no rest mass. However, the common misconception is with the past definition of mass which led to the photon being described with relativistic mass (or mass equivalent), which is just another way of saying energy. This in no way means that if you manage to grab a photon and weigh it on a scale, it has mass.

    Photons also do not have their own gravitational field. If you say they do due to being able to be bent around stars and planets, that is due to the curvature of space-time due to the massive object. The path of light is straight in the photon's frame, it just appears deflected to us. (General Relativity) You don't have any situations where photons are attracted to each other. (Which should happen if there were any form of attraction between the photons.)

    Regarding your box, I believe that is due to the pressure of electromagnetic radiation on the box. Yes, the mass of the box will increase, but it is not saying that light has mass, just that light with a box in total has a greater mass than just a box. This is rather wonky, I know.

    Anyway, if photons did have mass, people wouldn't be spending so much money on the LHC just to find the Higgs Boson, the particle supposedly explaining the mass between photons and matter.

    Also... Not all energy is in the form of photons. I can raise a book above a table, which results in the increase in potential energy. You would agree with me that the mass doesn't increase in any frame of the scenario. (Doesn't relate to the topic, but relates to your energy has mass statement.)
     
  10. Aug 6, 2011 #9
    Breaking apart an oxygen atom requires energy. Any atom lighter then iron requires energy to break them apart and energy is released when two atoms are fused into one e.g. Hydrogen fusion. For atoms heavier then iron it's the other way around. They release energy when breaking apart. e.g. uranium fission.
    When hydrogen fuses into helium the combined rest mass of all involved particles will decrease. That's called "mass defect". The lost mass is turned into light or heat. That shows that binding energy has mass.

    If photons don't create a gravitational field that would mean if you take some matter and antimatter and let them annihilate, the gravitational field would suddenly vanish.
    You can also look here
    http://en.wikipedia.org/wiki/Mass

    And about your book example. If I lift a book of the table I am converting chemical energy into potential energy. The total amount of energy stays the same and so the mass stays the same.
     
  11. Aug 6, 2011 #10
    The stress-energy tensor of general relativity includes momenta, among other things. I believe the folks who model stellar evolution have to take into account mass loss because of radiation.
     
  12. Aug 6, 2011 #11
    Last edited: Aug 6, 2011
  13. Aug 7, 2011 #12
    I just want to say that charged particles are affected differently in Gravitational fields.
     
  14. Oct 4, 2011 #13
    When I hear "chemical properties" I think more of nuclear properties, such as numbers of protons, neutrons, electrons. Because these all have a mass, then of course they would affect the gravitational force of that material. However, if it's a got a different mass, or charge, or whatever, it's a different material or particle, if you choose to define it as such. And by that fact, there WILL be a difference in how those particles interact. As someone else mentioned, there are a lot more 'terms' in general relativity that are taken into account when the calculations are done, that relate to what would be classified as 'chemical' properties. I suppose if you overlooked some of those then it would appear to violating some law, but it's not the case.
     
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