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Negative of (almost) everything

  1. Jun 21, 2010 #1
    I like to mess with the physical quantities
    Since i got interested in phiolosophy, I always wondered
    What phenomenon will we get if the following physical quantities are negative?

    Mass
    Electric potential
    Temperature
    Electric charge
    Amount
    Luminosity
    Time
    Electrical resistance
    Refractive index
    Pressure
    Thermal conductivity
    Weight
    Volume/Length, Area etc.
    Specific heat capacity
    particle spin


    In addition, a phiolosophical question
    Why are every entities (concepts, matter etc.) must have two sides (i.e. -+ or good evil)
    Is it possible to have any entity that is mono sided, if so what happens?
     
  2. jcsd
  3. Jun 21, 2010 #2
    Hi
    To me, negative of everything will just mean the shift of the scale. Say, 0kg becomes -1kg. The physical characteristics do not change;just the way how we see it is changed.

    I appreciate your philosophical approach. It can create new ideas.

    I do not understand well what you mean in the last paragraph. I would like to say there is no magnetic monopole.:smile:
     
  4. Jun 21, 2010 #3
    no! mono sided doesn't mean magnetic monopoles,
    it means entities with only evil or good

    The world (at least our own)
    seems to against this idea
    What's the problem if such mono sided entities exists?
     
  5. Jun 21, 2010 #4

    Office_Shredder

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    Is this supposed to be discussing physics or morality?
     
  6. Jun 21, 2010 #5
    Both physics and morality

    As i often like to treat morality as particles with charges
     
  7. Jun 21, 2010 #6
    physics is not about good or evil!
     
  8. Jun 21, 2010 #7
    Good and evil are part of a spectrum; they are not binary. That's why you cannot have one without the other.
     
  9. Jun 21, 2010 #8
    Sorry have to clarify that the 'negatives' of the physical quantities are negative as in direction, numbers, not moral value

    Only the phiolosophical question deals with moral negatives

    Also thanks for the advice

    Edit: after a while of seraching I've the following conclusions

    Negative gravity: Reverse gravity (in various sci fi)
    Negative Mass: ?
    Negative Electric potential: ?
    Negative (Kelvin) temperature: ?
    Negative Electric charge: e.g. electrons
    Negative amount: ?
    Negative Luminosity: ?
    Negative Time: Anti time/ backward flowing time (in star trek)
    Negative Electrical resistance: ?
    Negative Refractive index: Left handed metamaterials
    Negative Pressure: ?
    Negative Thermal conductivity: ?
    Negative Volume/Length, Area etc. : ???
    Negative Specific heat capacity: ?
    Negative particle spin: ?

    What will be the properties of matter with one or few of the above quantities negative (number)?
     
    Last edited: Jun 21, 2010
  10. Jun 21, 2010 #9
    Hmmm, this is rather entertaining.

    Mass - something with negative mass...which I believe would float away from anything with positive mass? Gravitationally speaking, it would have the opposite acceleration applied to it as something normal. So it would shoot away from earth at -9.8m/s^2, I think.
    Electric potential - ?
    Temperature - This is really a measure of energy. Negative energy would be...antimatter? So whatever the temperature of antimatter is might be your answer, haha.
    Electric charge - ?
    Amount - However much there is not...? I'm not sure on this one.
    Luminosity - Something that projects darkness. Imagine you're somewhere bright, and I hold up a lamp. It's perfectly black in the center. There seem to be "rays" of darkness that come out of it. Otherwise, we only have black holes in real life.
    Time - Hertz?
    Electrical resistance - electrical conductance, or 1/R
    Refractive index - ?
    Pressure - Negative pressure, I would assume. Not too sure.
    Thermal conductivity - thermal resistance :D
    Weight - ?
    Volume/Length, Area etc. - ?
    Specific heat capacity - ?
    particle spin - ?

    You could probably kind of cheat on any one of these by taking the units of the quantity in question and just invert the unit. What those inverted quantities mean physically is a whole different matter. An example was electrical resistance vs electrical conductance, but those make intuitive sense. Some others might not...

    Out of all the answers I gave, I'm really only happy with my answer to luminosity.

    As for your two sided thing, I think the answer you're looking for is that systems of measurement MUST be relative. Otherwise, what is there to measure? I might give more thought to this later, but for now I have to go.
     
  11. Jun 21, 2010 #10

    Ygggdrasil

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    Some people would claim a system in population inversion (such as is found in a laser) has a negative temperature. This comes from defining temperature in a statistical mechanical way (from the Boltzmann distribution). Of course, this definition is valid only for systems at equilibrium (systems in population inversion cannot be at equilibrium) and does not jive with other definitions of temperature (e.g. the average kinetic energy of the system).
     
  12. Jun 22, 2010 #11
    Negative temperature applies to quasiparticles that have negative relative energy. That means, the more particles of this kind, the less energy. Note that "zero" energy is not vacuum, it is some positive amount of joules. It is not negative absolute energy.
    An example of such particles are holes in semiconductors. It's simply lack of an electron. The more holes, the less energy. These holes have negative absolute temperature, since adding energy leads to decrease of entropy.

    Negative resistance is also a common thing. There are electronic devices that give current of reversed sign relative to applied voltage. Of course, these things require external power source.

    Bodies of negative charge emit negative electric potential.

    Negative pressure is an effect of cosmological constant. It's antigravity of a kind, since it makes our universe expand. Superrelativistic gas (i.e. space filled with light) can have negative pressure.

    Negative time means nothing. It's the matter of drawing an arrow. No physical consequences.

    Negative particle spin - just as with electrical charge, i.e. antimatter.

    Negative length, area and volume - it's just Minkowski spacetime. Time dimension is positive length, space is negative (matter of convention, actually). Positive area is an area of dimensions of one kind (space-space), negative area is composed of different dimensions (time-space).

    And there is such thing as quantum phase. It may refer to negative amount (or rather complex amount). In double-slit experiment we get places, where no photon hits. In fact, there is positive quantity of a photon flowing from one slit and equal negative amount from second slit. They cancel out to zero.
    So, there may exist such thing as negative physical amount. Fractional amount appears to us as probability.
     
  13. Jun 22, 2010 #12
    Negative particle spin: So does that means some sort of "anti spin matter"? , Will it behaves like antimatter (charged reversed) when collided with normal matter (from equations) ?

    Negative temperature: So what would that thing be if it has 0 absolute energy?

    Negative resistance: I never heard of that before, mind give some examples, explanations and insights?

    Negative pressure: Woa I thought it will behave differently from antigravity (reverse gravity). So it'll just push things outwards, right?

    Negative time: will make another thread to discuss this in detail, such as the concept of future and past and casuality

    Negative amount: Now that's suprising, I can't believe such thing can exist!
     
  14. Jun 22, 2010 #13
    Yes, it's THE antimatter. When you have two electrically neutral particles with opposite spin, then they are mutually antiparticles.

    It's impossible for vacuum case. You cannot dig holes in the vacuum, since you can't take from it any more energy (by definition). You can only have holes in something that exists.

    Here you are: http://en.wikipedia.org/wiki/Negative_resistance
    It can be used as a stabilizer.

    Actually, it's a bit more complicated :). It's just like a vacuum cleaner (sucks everything), but it's a self-amplifying phenomenon, kinda perpetuum mobile. In effect, it leads to exponential expansion of the spacetime - namely cosmic inflation.
    You'll need hard maths to understand it well.

    No one does :).
     
  15. Jul 2, 2010 #14
    That would be a Mobius strip psychosis.
     
  16. Jul 2, 2010 #15
    [strike]Secret[/strike] has been negated.
     
  17. Aug 3, 2010 #16
    Oh wee. He must have been too negative

    :yuck:
     
  18. Aug 3, 2010 #17

    cronxeh

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    Oh Snap :rofl:

    Before this is locked, I wonder on a more 'whatever, its a Tuesday' theme..

    Would negative temperature be negative entropy, I.e at zero kelvin you have zero entropy, so would you need to borrow energy from some other universe? Suppose you no longer emit energy, would you start absorbing it from the vacuum of space?
     
  19. Aug 3, 2010 #18
    I have seen a post (I think on this forum) that actually explains that negative temperatures actually do exist or are physically meaningfull, yet they don't signify temperatures lower then 0 K, but actually temperatures that are higher then the highest positive temperature. That is to say the termperature scale would then be:

    0K ...... (positive infinite temperature) (negative infinite temperature) .... -0K

    So, -0K would be the highest temperature.

    For explenation, I need to refind that thread....
     
  20. Aug 3, 2010 #19
    hmmm.... and adding one more negative thing....

    How about the hypothetical existence of matter with negative mass?

    Is it impossible? And if yes, based on what?
     
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