- #1
FrankPlanck
- 31
- 0
Hi everyone,
I'm new here, I have just discovered this forum and I think it will be very useful!
First of all I would like to apologize for my english because I'm not a native english speaker (you are allowed to point out my errors ).
Anyway... this is the problem:
when we speak about interstellar clouds or, in general, about thermodynamics in astrophysics, we meet whit 3 types of energy:
- internal
- thermal
- kinetic
I think that I have understood the difference between internal and thermal energy:
the internal energy is the sum of "kinetics" contributions of the gas molecules (traslational, vibrational and rotational) + "zero point" energy. The thermal energy, that can be transmitted thru heat, is the sum of translational, vibrational and rotational energy.
Hence thermal energy = internal energy - "zero point" energy
Often, when we speak about gas clouds or about astrophysics phenomena, we clearly distinguish thermal and kinetic energy.
Hence the question: the thermal energy is the average kinetic energy of the gas particles... and so what is kinetic energy?
Let's take the simplest case: an hot intestellar cloud (T about 10^9 K) and so fully ionized gas (there is only translational contribution).
I think that the thermal energy quantifies the level of kinetic "agitation" of the particles (in random and untidy motion), in fact we can associate thermal energy with temperature.
Instead the kinetic energy quantifies an ordered flux of particles in a given direction.
Hence, even if they represent the kinetic motion of the particles, we can say that: if kinetic energy prevails the cloud will modify its shape, elongating in a given direction.
If thermal energy prevails there will not be the extension and my cloud will follow the usual thermodynamics laws.
Hence we can also say that in a gas cloud the energy is mainly thermal or kinetic because if one of these prevails the other decreases.
Is my interpretation correct?
Where do I make mistake?
Thank you!
Bye
I'm new here, I have just discovered this forum and I think it will be very useful!
First of all I would like to apologize for my english because I'm not a native english speaker (you are allowed to point out my errors ).
Anyway... this is the problem:
when we speak about interstellar clouds or, in general, about thermodynamics in astrophysics, we meet whit 3 types of energy:
- internal
- thermal
- kinetic
I think that I have understood the difference between internal and thermal energy:
the internal energy is the sum of "kinetics" contributions of the gas molecules (traslational, vibrational and rotational) + "zero point" energy. The thermal energy, that can be transmitted thru heat, is the sum of translational, vibrational and rotational energy.
Hence thermal energy = internal energy - "zero point" energy
Often, when we speak about gas clouds or about astrophysics phenomena, we clearly distinguish thermal and kinetic energy.
Hence the question: the thermal energy is the average kinetic energy of the gas particles... and so what is kinetic energy?
Let's take the simplest case: an hot intestellar cloud (T about 10^9 K) and so fully ionized gas (there is only translational contribution).
I think that the thermal energy quantifies the level of kinetic "agitation" of the particles (in random and untidy motion), in fact we can associate thermal energy with temperature.
Instead the kinetic energy quantifies an ordered flux of particles in a given direction.
Hence, even if they represent the kinetic motion of the particles, we can say that: if kinetic energy prevails the cloud will modify its shape, elongating in a given direction.
If thermal energy prevails there will not be the extension and my cloud will follow the usual thermodynamics laws.
Hence we can also say that in a gas cloud the energy is mainly thermal or kinetic because if one of these prevails the other decreases.
Is my interpretation correct?
Where do I make mistake?
Thank you!
Bye