Laws clearly state matter couldn`t be destroyed

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So there is a reaction where nothing but energy is produced? Normal low energy electron-positron annihilation, right?
 
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fedorfan said:
So there is a reaction where nothing but energy is produced? Normal low energy electron-positron annihilation, right?

If the energy of the electron positron annihilation is too low to support massive particles, it produces photons. No lower limit on the amount of energy that photons can carry, just make the wave lengths longer.

There is no such thing as pure energy.
 
Thats what I've been asking, ok, so you can't turn matter into pure energy. It always shows up on the subatomic scale or somewhere else. Thanks
 
fedorfan said:
Thats what I've been asking, ok, so you can't turn matter into pure energy. It always shows up on the subatomic scale or somewhere else. Thanks
Well photons have no rest mass (but they do have momentum (p = E/c), so in one sense, they are pure energy. Sorry if that makes some physicists cringe.
 
Astronuc said:
Well photons have no rest mass (but they do have momentum (p = E/c), so in one sense, they are pure energy. Sorry if that makes some physicists cringe.

Nah, the photon has chirality, it has this complicated relationship with the Z and W particles, and pretty generally its lack of mass doesn't keep it from having properties; gee, look at the way the photons behave in the delayed choice quantum eraser! For starters you have to be able to entangle them. Pure energy? Are you kidding?
 
Clearly I have some catching up to do. So by virtue of having properties, such as chirality, a photon cannot be considered pure energy?

Energy is left then to potential and kinetic energy?
 
Astronuc said:
Clearly I have some catching up to do. So by virtue of having properties, such as chirality, a photon cannot be considered pure energy?

Energy is left then to potential and kinetic energy?


I believe the mass-equivalence is considered a form of potential energy so I would say yes, physicsts find that to be enough; energy is either in some "stored" form manifested in the position or state of matter, or in some moving form manifested in the motion of matter. This would go well with their habit of developing their theories from a Lagrangian or Hamiltonian principle.

Or consider the relativistic energy equation
[tex]E^2 = p^2c^2 + m^2c^4[/tex]

The first term on the right would be the kinetic energy of a particle (including a massless one) traveling with momentum p, and the second term would be the rest frame energy of a massive particle.