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

  • #1
Feynstein100
89
9
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.
 

Answers and Replies

  • #2
berkeman
Mentor
64,182
15,409
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?
 
  • Like
Likes topsquark
  • #3
Orodruin
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Gold Member
20,004
10,650
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.
 
  • Like
Likes Klystron and topsquark
  • #4
Feynstein100
89
9
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?
 
  • #5
fresh_42
Mentor
Insights Author
2022 Award
17,645
18,345
This sounds to me like asking for a macroscopic object that violates the second law of thermodynamics.
 
  • Like
Likes topsquark
  • #6
Feynstein100
89
9
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? 😋
 
  • #7
fresh_42
Mentor
Insights Author
2022 Award
17,645
18,345
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.
 
  • Like
Likes topsquark
  • #8
berkeman
Mentor
64,182
15,409
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"
 
  • Like
Likes topsquark
  • #9
Feynstein100
89
9
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? 😵
 
  • #10
PeroK
Science Advisor
Homework Helper
Insights Author
Gold Member
2022 Award
23,784
15,399
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.
 
  • Like
Likes topsquark
  • #11
Feynstein100
89
9
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
 
  • #12
PeroK
Science Advisor
Homework Helper
Insights Author
Gold Member
2022 Award
23,784
15,399
  • #13
Feynstein100
89
9
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? 🤔
 
  • #14
berkeman
Mentor
64,182
15,409
since they are supposed to be macroscopic nuclei (not literally, I know but in principle).
What does that mean?
 
  • #15
Feynstein100
89
9
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.
 
  • #16
berkeman
Mentor
64,182
15,409
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...
 

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

Replies
16
Views
296
Replies
4
Views
490
  • Last Post
Replies
6
Views
881
Replies
2
Views
450
Replies
39
Views
2K
Replies
5
Views
796
  • Last Post
Replies
29
Views
2K
Top