<p>Firstly, black holes and <em>wormholes</em> are different. Wormholes contain &quot;exotic&quot; matter, due to which the curvature effects become repulsive. These violate the average null energy condition, or in general they do not satisfy <span class="math-container">$T_{\mu \nu }X^{\mu }X^{\nu }\geq 0$</span>. Due to this, the field equations imply that <span class="math-container">$G_{\mu \nu }&lt;0$</span>. Black holes on the other hand satisfy the usual energy conditions like the null energy condition, due to which they do not contain negative energy. This should be clear from any introductory GR text like Hawking and Ellis. Second, this is not &quot;space&quot; or astronomy for that matter. This is a part of theoretical physics, called general relativity. See for instance, Hawking and Ellis (1973) or Misner, Thorne and Wheeler (1973) for a good introduction to what these things are.</p>

CC BY-SA 4.0
2023-09-29T11:31:13.527Z
Not sure OP is going to be able to get much from this answer...
AtmosphericPrisonEscape
CC BY-SA 4.0
2023-09-29T12:39:28.060Z
@AtmosphericPrisonEscape How so? I answered the question because it has a formal implication. I (1) detailed on what the meaning of the question was, since OP did not clarify what was meant by "negative energy", (2) detailed some technical aspects because that is what general relativity is, and (3) suggested a book to consider for an introduction to these things. Keep in mind that this is a question that belongs to phys.SE and not astronomy.SE. Not sure how OP is "not going to get much", but ok.
VaibhavK
CC BY-SA 4.0
2023-09-29T17:54:13.080Z
Hawking and Ellis definitely is not an introductory GR text.
TimRias
CC BY-SA 4.0
2023-09-29T17:57:40.560Z
No, it is definitely not. However, in case OP didn't want a mathematical introduction, a more elegant exposition is offered in MTW, which I also cited. The point is that there is a certain amount of gravity (no pun intended) that the proper mathematical description has. Seeing as the question seemed as if it was of the type to be posted on phys.SE, I gave a suitable explanation.
VaibhavK
CC BY-SA 4.0
2023-09-30T00:41:40.503Z
From OP: "as space is not my bailiwick." I can't imagine how you think that OP is even remotely familiar with math. So going in there throwing around the GR-bomb is grossly failing the science communication exam. 
Also not sure where your wormholes are supposed to relate to this?
AtmosphericPrisonEscape
CC BY-SA 4.0
2023-09-30T04:17:42.440Z
@AtmosphericPrisonEscape I know that OP was probably not familiar. However, the point of SE is to answer questions because there are others consulting the question too. For the OP if it weren't helpful, I would understand it and gladly explain more layman-ly. However, the point of the answer is to do better than that for _generally_ anyone reading it. This post seemed like a phys.SE-type post, so I explained how I would; not just for OP or to give a half-straightened explanation, but to answer the question at least to a certain point. So this is not a "GR-bomb".
VaibhavK
CC BY-SA 4.0
2023-09-30T04:20:38.747Z
@AtmosphericPrisonEscape I had to presume OP meant by "negative energy" exotic contributions to the EFEs, so I had to explain that on the contrary to wormholes (which in pure GR are made of exotic contributions), black holes do not have any of those exotic things. I am not sure what the issue is here -- if OP did not find it helpful they could always ask for a better description. However, I do not understand other people having problems with the answer; it isn't wrong, it isn't a half-brained mess -- what is the issue here? Other than OP there are other people viewing this question as well.
VaibhavK
CC BY-SA 4.0
2023-09-30T05:36:25.583Z
Why are you talking about wormholes? The OP makes no mention of them.
PM 2Ring
CC BY-SA 4.0
2023-09-30T06:27:09.790Z
@PM2Ring I presumed by negative energy OP meant exotic matter contributions. These are characteristic in wormhole solutions, _not_ black holes like OP mentioned, so I said that black holes typically do not contain such kind of things, and instead preserve things like the null energy condition and so on.
VaibhavK
CC BY-SA 4.0
2023-10-13T20:01:24.553Z
Wow... This exchange is passively toxic.
Bill Joe
CC BY-SA 4.0
2024-03-05T12:22:02.597Z
@BillJoe Not sure -- but I basically answered what I felt would be nice, and somehow this offended some people.
VaibhavK
CC BY-SA 4.0
2023-09-29T06:13:01.213Z
2023-09-29T06:13:01.213Z
VaibhavK
<p>Nice question! It is indeed taking part in ending the black hole in but it is not &quot;stored&quot; in the classical sense. To be specific, when an sudden matter-antimatter pair pops up in the vacuum of space and somehow don't get annihilated, and one of them falls into the event horizon whereas the other escapes into infinity of space. In this case one of them inside the ergosphere, due to the gravitational forces becomes &quot;negative energy&quot; and falls into the black hole whereas the other one escaping has real energy. The tiny amount of negative energy enters the event horizon and since all the matter entering has the singularity in the future of their light cone unless it is some sort of ring singularity it has to encounter, possible in the case of Kerr black holes. Somehow even the information paradox, the event horizon does not strip off it's energy condition. Then the singularity gets slowly evaporated because the negative energy nullifies the positive energy contained inside the event horizon, playing a role in the hawking radiation (which violates the energy condition of black holes) and causing the end of the black hole era.</p>
<p>Thank you!</p>

CC BY-SA 4.0
2023-09-29T08:56:53.023Z
2023-09-29T12:45:26.260Z
2023-09-29T12:45:26.260Z
Arjun
<p>new to the community here. The question I have is whether black holes can possibly contain negative energy of any sort?</p>
<p>It’s not a carefully thought-out question as space is not my bailiwick.</p>

<black-hole>
Possibility for black holes having negative energy
Bill Joe
# Possibility for black holes having negative energy

(Asked by: username_0 on 2023-09-29)

new to the community here. The question I have is whether black holes can possibly contain negative energy of any sort?

It’s not a carefully thought-out question as space is not my bailiwick.

**Tags:** black-hole


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## 2 answers

### Answer by username_1 on 2023-09-29. Score: -1

Firstly, black holes and *wormholes* are different. Wormholes contain "exotic" matter, due to which the curvature effects become repulsive. These violate the average null energy condition, or in general they do not satisfy $T\_{\mu \nu }X^{\mu }X^{\nu }\geq 0$. Due to this, the field equations imply that $G\_{\mu \nu }<0$. Black holes on the other hand satisfy the usual energy conditions like the null energy condition, due to which they do not contain negative energy. This should be clear from any introductory GR text like Hawking and Ellis. Second, this is not "space" or astronomy for that matter. This is a part of theoretical physics, called general relativity. See for instance, Hawking and Ellis (1973) or Misner, Thorne and Wheeler (1973) for a good introduction to what these things are.

> **Comments:**
> **username_2**: Not sure OP is going to be able to get much from this answer...  
> **username_1**: @username_2 How so? I answered the question because it has a formal implication. I (1) detailed on what the meaning of the question was, since OP did not clarify what was meant by "negative energy", (2) detailed some technical aspects because that is what general relativity is, and (3) suggested a book to consider for an introduction to these things. Keep in mind that this is a question that belongs to phys.SE and not astronomy.SE. Not sure how OP is "not going to get much", but ok.  
> **username_3**: Hawking and Ellis definitely is not an introductory GR text.  
> **username_1**: No, it is definitely not. However, in case OP didn't want a mathematical introduction, a more elegant exposition is offered in MTW, which I also cited. The point is that there is a certain amount of gravity (no pun intended) that the proper mathematical description has. Seeing as the question seemed as if it was of the type to be posted on phys.SE, I gave a suitable explanation.  
> **username_2**: From OP: "as space is not my bailiwick." I can't imagine how you think that OP is even remotely familiar with math. So going in there throwing around the GR-bomb is grossly failing the science communication exam.  Also not sure where your wormholes are supposed to relate to this?  
> **username_1**: @username_2 I know that OP was probably not familiar. However, the point of SE is to answer questions because there are others consulting the question too. For the OP if it weren't helpful, I would understand it and gladly explain more layman-ly. However, the point of the answer is to do better than that for _generally_ anyone reading it. This post seemed like a phys.SE-type post, so I explained how I would; not just for OP or to give a half-straightened explanation, but to answer the question at least to a certain point. So this is not a "GR-bomb".  
> **username_1**: @username_2 I had to presume OP meant by "negative energy" exotic contributions to the EFEs, so I had to explain that on the contrary to wormholes (which in pure GR are made of exotic contributions), black holes do not have any of those exotic things. I am not sure what the issue is here -- if OP did not find it helpful they could always ask for a better description. However, I do not understand other people having problems with the answer; it isn't wrong, it isn't a half-brained mess -- what is the issue here? Other than OP there are other people viewing this question as well.  
> **username_4**: Why are you talking about wormholes? The OP makes no mention of them.  
> **username_1**: @PM2Ring I presumed by negative energy OP meant exotic matter contributions. These are characteristic in wormhole solutions, _not_ black holes like OP mentioned, so I said that black holes typically do not contain such kind of things, and instead preserve things like the null energy condition and so on.  
> **username_0**: Wow... This exchange is passively toxic.  
> **username_1**: @BillJoe Not sure -- but I basically answered what I felt would be nice, and somehow this offended some people.  

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### Answer by username_5 on 2023-09-29. Score: -2

Nice question! It is indeed taking part in ending the black hole in but it is not "stored" in the classical sense. To be specific, when an sudden matter-antimatter pair pops up in the vacuum of space and somehow don't get annihilated, and one of them falls into the event horizon whereas the other escapes into infinity of space. In this case one of them inside the ergosphere, due to the gravitational forces becomes "negative energy" and falls into the black hole whereas the other one escaping has real energy. The tiny amount of negative energy enters the event horizon and since all the matter entering has the singularity in the future of their light cone unless it is some sort of ring singularity it has to encounter, possible in the case of Kerr black holes. Somehow even the information paradox, the event horizon does not strip off it's energy condition. Then the singularity gets slowly evaporated because the negative energy nullifies the positive energy contained inside the event horizon, playing a role in the hawking radiation (which violates the energy condition of black holes) and causing the end of the black hole era.

Thank you!


---

