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What is the essence of universe: energy or matter?

  1. May 30, 2005 #1
    what is the essence of the universe: energy or matter?

    Who can tell me the relationship of matter (mass) and energy? it seems that they are not independent. as I think about this question, others comes up as to whether matter can be separated endless, and what the elementary particles are. so far, we know that quark is the smallest particle. but, can we assert quark will be able to stand with stronger high-energy bombardment, which is inaccessible today? i have a feeling that eventually elementary particle might be smallest energy unit? according to this, it seems that matter is energy in nature. is this true? Thanks.
    Last edited: May 30, 2005
  2. jcsd
  3. May 30, 2005 #2


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    In the rest frame of any particle, its energy is given by [tex]E = mc^2[/tex], where E is its energy, m is its mass, and c is the speed of light. If you're not familiar with the notation, the two things on the right of the equals sign are multiplied together, mass times the square of the speed of light.

    For any other unaccelerated observer moving with velocity v relative to the particle (or seeing the particle move with velocity v), its energy is [tex]E_v = \gamma mc^2[/tex], where
    [tex]\gamma = \frac{1}{\sqrt{1 - \frac{v^2}{c^2}}}[/tex].

    The factor [tex]\gamma[/tex] allows both for the fact that the particle has a momentum in the observer's frame of reference, and also for the relativistic change to the energy because of the speed difference.
    Last edited: May 30, 2005
  4. May 30, 2005 #3
    Thank you, selfAdjoint.. Einstein's mass-energy equation just tells us how the REST energy is related to mass. we also know that there are other forms of energy like phonon, electromagnetic waves which are mass independent. Although these kinds of energy can be absorbed by matter so as to change the state of matter, it is not substantiated after all. so, can I say that matter is the carrier of SOME of energy, or, to some extent, matter is partial manifestation of the total energy in the universe?
    Last edited: May 31, 2005
  5. May 31, 2005 #4
    the Quark is far larger than the Electron, i think, i have only known such particles to be described through their mass not their 'size'
  6. May 31, 2005 #5
    Hi Wangasu

    Einstein's famous formula tells us that mass and energy are the same thing, related by the speed of light, which is a constant. The gamma term in the second equation selfAdjoint gave you tells us how the observed mass of a body changes with velocity, as measured by the observer.

    It may be a mistake to think of mass as the carrior of energy. It is not known what mass really is, but I for one am almost certain it does not consist of tiny little balls of hard heavy stuff. Many students of this question have found it best to study the math and not get too involved in thinking about what it "really" is. How does it behave? That is something we can measure and talk about meaningfully.

    Hi, Hexhunter.

    Your idea that quarks are bigger than electrons may have no meaning at such tiny scales. Heisenburg uncertainty principle makes such comparisons useless.

    Thanks for being here,

  7. May 31, 2005 #6


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    Physical quarks are still sometimes called by the name they got (from Feynmann, I believe) when they were first detected at SLAC back in the 1960s: partons. And they are essentially dimensionless particles wandering around inside the proton and neutron. Was it those particles you had in mind when you said they were bigger than the electron?
  8. May 31, 2005 #7
    This is the essential part of the quantum to matter relationship, and is best defined over time by beginning with the statement, a natural flow-on of Newton's third law -
    and I only got it last week - "When a force is applied to a material object, it remains with that object and adds to its mass". When the thought came, it was like someone saying ' hey go back to first principles as this is a required part of the journey ' - I thought about the action of energy, and that it can travel from molecule to molecule as required by gravity, inertia and other friction-creating phenomena. This works, and leads to the next part of the revelation, which is to do with the four manifestations of energy (some say 10 or 11, and that could be proven right as time goes by).
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