Prospective author needs some commentary...

[allydeckhard]

So, I studied biology...not physics. I did my homework on relativistic and quantum physics, but I don't consider myself an expert on high energy physics and cosmology.

 

I'm writing a novel, and one of my characters is a physics student. I'd like to confirm that what he says is accurate under the consensus of modern understanding.

 

One of the statements that my character makes is: "Matter and energy are the same thing, they are merely in different states of motion."

 

I feel confident that my character is making an accurate statement given current understanding.

 

I understand that--without drowning someone in a lagoon of mathematics--in the context of relativistic physics, that mass, a measure of matter, can be expressed in electron volts, etc. I also understand that, because of the equivalence principle, that matter and energy are the same 'thing'. (Whatever the heck that 'thing' is...but that's another story.)

 

A Hicks quote states that matter is "energy condensed to a slow vibration." Although, this is a quote that makes a comment about psychedelic drugs, so one must clearly take this with a grain of salt.

 

This clearly ties into the roots of Big Bang and relativity, which I am inexpert in.

 

I believe in Big Bang...recognize the universe as a thermodynamic system guided by the second law...etc.

 

Assuming that the universe is an isolated system, I want my character to say: "The universe is cooling and slowing as time progresses." Is that an accurate statement given current understanding?

 

Any feedback about the accuracy of these statements would be appreciated.

 

Thanks!

 

 

 

 

[Klaynos]

I would disagree partly with your first statement. It is fairer to say something like mass is a form of energy or mass and energy are two forms of the same thing. The thing is mass-energy. I'd not mention motion.

 

Your second comment whilst was once thought to be true and is certainly the most intuitive is not true. The universal expansion is getting faster, not slowing down. The reason for this is currently unclear but the name of the energy associated with this is dark energy.

[ajb]

One of the statements that my character makes is: "Matter and energy are the same thing, they are merely in different states of motion."

That is not really how people understand it. I think you are trying to make a statement about E=mc^2?

 

Really this tells us that the mass of an object needs to be included in the total energy. In this sense, one loosely can think mass as a kind of energy, but I would be careful taking that too far. One can also say the same about momentum as it also appears in the full equation E^2-p^{2}c^2 = mc^2.

 

A Hicks quote states that matter is "energy condensed to a slow vibration." Although, this is a quote that makes a comment about psychedelic drugs, so one must clearly take this with a grain of salt.

Energy is a property of some physical configuration of fields, particles or whatever. It does not exists as a thing in its own right. So I am not sure what the quote has to do with physics.

 

 

Assuming that the universe is an isolated system, I want my character to say: "The universe is cooling and slowing as time progresses." Is that an accurate statement given current understanding?

That seems okay, usually one is talking about the CMBR when temperature and cooling are mentioned.

 

I am far from an expert in this, but there is evidence that the Universe has cooled just as the standard model of cosmology predicts it would.

[swansont]

I'll be the third physics type to agree that the character would/should say that mass is a form of energy. Further, this is not the equivalence principle, which tells us that gravity is indistinguishable from acceleration.

[allydeckhard]

That seems okay, usually one is talking about the CMBR when temperature and cooling are mentioned.

 

I am far from an expert in this, but there is evidence that the Universe has cooled just as the standard model of cosmology predicts it would.

 

It actually occurred to me after I left the library that I stated that it is cooling and slowing. After thinking about the definition of temperature, I said to myself...well...what's the difference between cooling and slowing? That's redundant, isn't it?

 

Hmm...I went over the Big Bang and CMB entries on Wikipedia and it does indicate that it is cooling. It seems to me that radiation is being converted to matter as time goes progresses, which is a bit of a restatement of what I wrote earlier. If it is cooling, then by the conservation laws the energy isn't being destroyed. Thanks to the relativistic definition of matter, this leads me to conclude that photons are being converted to matter--which travels at a slower rate than photons. Therefore: slowing (not the expansion...the energy) and cooling?

[Delta1212]

 

It actually occurred to me after I left the library that I stated that it is cooling and slowing. After thinking about the definition of temperature, I said to myself...well...what's the difference between cooling and slowing? That's redundant, isn't it?

 

Hmm...I went over the Big Bang and CMB entries on Wikipedia and it does indicate that it is cooling. It seems to me that radiation is being converted to matter as time goes progresses, which is a bit of a restatement of what I wrote earlier. If it is cooling, then by the conservation laws the energy isn't being destroyed. Thanks to the relativistic definition of matter, this leads me to conclude that photons are being converted to matter--which travels at a slower rate than photons. Therefore: slowing (not the expansion...the energy) and cooling?

That's really, really not how it works.

 

The universe is cooling in the sense that the energy density is decreasing as the universe expands. There's a set amount of energy in the universe, but as the universe expands, the amount of energy per some set volume of space decreases.

 

Individual particles aren't slowing down and photons are certainly not cooling into massive particles.

[ajb]

It seems to me that radiation is being converted to matter as time goes progresses, which is a bit of a restatement of what I wrote earlier.

That is not what is happening.

 

If it is cooling, then by the conservation laws the energy isn't being destroyed.

Conservation of energy is a much more subtle issue here. I am not sure how much to say right now, but as we have an expanding Universe, in particular it is not static one does not have global conservation of energy in the same way one would on a flat static space-time.

 

Thanks to the relativistic definition of matter, this leads me to conclude that photons are being converted to matter--which travels at a slower rate than photons.

You also need to think about the conservation of momentum here, as well as the other quantum numbers. Anyway, that is not what we see happening.