Could there be macro objects out there that convert energy to mass?

[Feynstein100]

Stars are basically large objects that convert mass to energy as allowed by the mass-energy equivalence in special relativity. So I was thinking, following the same equivalence, shouldn't the reverse be possible too? I.e. a kind of reverse star that sucks in energy and converts it into mass?

I know about pair production but it only happens in the quantum scale. I was wondering if it could be possible in the macro scale too. Imagine if we could convert dark energy into matter.

 

[berkeman]

So I was thinking, following the same equivalence, shouldn't the reverse be possible too? I.e. a kind of reverse star that sucks in energy and converts it into mass?

A black hole absorbing photons of all energies?

 

[Orodruin]

The premise of the question is flawed as the mass-energy equivalence is not about converting mass to energy (although this way of talking is often used in popularised contexts). It is really about inertia in the rest frame being equivalent to rest energy. Energy is a property, not a thing in itself. However, energy of one form may be converted to other forms.

 

[Feynstein100]

A black hole absorbing photons of all energies?

Technically, yeah but idk if the photons get converted to mass inside the horizon so I didn't count it. I mean, do they?

 

[fresh_42]

This sounds to me like asking for a macroscopic object that violates the second law of thermodynamics.

 

[Feynstein100]

This sounds to me like asking for a macroscopic object that violates the second law of thermodynamics.

Lmao why is that? Really, it's not that implausible. I mean, I mentioned pair production, didn't I?

 

[fresh_42]

Lmao why is that? Really, it's not that implausible. I mean, I mentioned pair production, didn't I?

If you phrase your question in a way that allows a qualitative answer you will sooner or later be forced to implicitly define the entropy before and after that hypothetical process. My suspicion is, that your matter object is of less entropy than your energy world.

 

[berkeman]

Lmao why is that? Really, it's not that implausible. I mean, I mentioned pair production, didn't I?

Thread discussion level changed from "I"-->"B"

 

[Feynstein100]

If you phrase your question in a way that allows a qualitative answer you will sooner or later be forced to implicitly define the entropy before and after that hypothetical process. My suspicion is, that your matter object is of less entropy than your energy world.

Interesting idea. I'm actually not clear as to whether entropy is a property of matter or energy. Hmm although, isn't energy already a property of matter? So can a property have a property?

 

[PeroK]

Lmao why is that? Really, it's not that implausible. I mean, I mentioned pair production, didn't I?

What you are really looking for is a scenario on a large scale where high energy particles collide (or otherwise interact) to produce particles of greater total rest mass. I think the main problem is the energies of the particles must be higher than would be found naturally in large scale collisions. It could happen in isolated cases, but it's difficult to see how nature could create a high energy particle collider on a large scale.

 

[Feynstein100]

What you are really looking for is a scenario on a large scale where high energy particles collide (or otherwise interact) to produce particles of greater total rest mass. I think the main problem is the energies of the particles must be higher than would be found naturally in large scale collisions. It could happen in isolated cases, but it's difficult to see how nature could create a high energy particle collider on a large scale.

That's an interesting thought and kind of sounds like reverse fusion to me lol. Wait, isn't that just fission? No, this is something different. Fission still releases energy by destroying mass.
Although, this reverse fusion looks identical to fission. It'd just be a kind of forced fission where elements lighter than iron are split into smaller, but more massive elements by adding energy. This would be analogous to fusing radioactive elements into more massive ones by expending energy. Huh.
That's one way of doing it, I suppose. But yeah. It's definitely not going to happen in nature because you're pushing matter into higher energy states instead of lower. There could be another way though

 

[PeroK]

There could be another way though

I'll let you ponder that one.

 

[Feynstein100]

I'll let you ponder that one.

I'm kind of wondering about pair production around neutron stars, since they are supposed to be macroscopic nuclei (not literally, I know but in principle). Would that be possible?

 

[berkeman]

since they are supposed to be macroscopic nuclei (not literally, I know but in principle).

What does that mean?

 

[Feynstein100]

What does that mean?

There's this pop sci notion (originally attributed to the YouTube channel Kurzgesagt, I think) that a neutron star is basically just a giant atomic nucleus, since it's made up of only nucleons and has similar densities. It's not meant to be scientific, of course but I find it helpful to indulge in the analogy sometimes. Hence my question. If neutron stars are equivalent to nuclei and pair production happens around nuclei, could it also happen around neutron stars?

Here's the video in case you're interested.

 

[berkeman]

There's this pop sci notion (originally attributed to the YouTube channel Kurzgesagt, I think) that a neutron star is basically just a giant atomic nucleus, since it's made up of only nucleons and has similar densities. It's not meant to be scientific, of course but I find it helpful to indulge in the analogy sometimes.

We don't discuss pop-sci ideas or references in the technical forums at PF. You should know that by now. Thread is locked for a bit...