Dark stars as a cosmic window on a mirror world


A couple of weeks ago, I introduced the concept of a mirror world as a viable option for dark matter. I would like to push this concept further, and discuss how mirror stars made of dark matter (i.e. dark stars) could send us detectable cosmic ray signals.


[image credits: @pab.ink]

Crossing the mirror…

Hidden worlds refer to setups in which the matter content of the universe is split into two sets. The first set ( i.e. the visible world) consists in all known particles, whilst the second set (i.e. the hidden world) contains new hypothetical particles, the lightest one being dark matter.

In the visible world, the fundamental particles of the Standard Model interact through electromagnetism, the weak and the strong interactions. On the other hand, the hidden particles interact through new interactions (to which the visible particles are insensitive to).


[image credits: new 1lluminati (CC BY 2.0)]

In a mirror world configuration, the hidden world includes copies of each known particle: mirror quarks, mirror electrons, etc.

The mirror particles moreover undergo mirror versions of the Standard Model interactions: mirror electromagnetism, mirror weak and mirror strong interactions.

We hence end up with two independent copies of the Standard Model: a visible one and a mirror one.

As in the visible sector, mirror composite objects (like mirror neutrons and protons, but also mirror stars) can be formed.


The bright and dark side of electromagnetism


[image credits: NASA]

Electromagnetism is a special force: a photon (the mediator of the electromagnetic interactions) does not interact with itself, in contrast with the other interactions.

The same holds for the mirror (or dark) photon.

This has a deep consequence: usual and dark photons mix. On very rare occasions, a visible photon can hence be converted into a dark photon, and vice versa.


A mirror star cosmic ray signal

This photon/dark photon mixing provides a way to the mirror and the visible worlds to communicate. This has many consequences. In particular, visible matter can be captured by a mirror star, which leads to the formation of a nugget of visible matter within the mirror star. Such a nugget could then further collide with mirror objects.

This results in the emission of an X-ray signal that could be detected in space observatories like Gaia or Chandra, as illustrated below.


[image credits: arxiv]

This figure shows the luminosity of the X-ray signature of the mirror star (y-axis) as a function of its temperature (x-axis).

Each colour (orange, red, purple) corresponds to a specific mirror star mass, the orange being a mirror sun. The results for a strong (but not experimentally excluded) photon mixing are represented by dashed lines, and the dotted lines correspond to a 100 times weaker mixing.

The solid lines estimate the distance at which a signal of a given luminosity and temperature could be detected by Gaia (blue) and Chandra (green). In order to understand this figure, let us focus on few examples.

A mirror sun with a large mixing emitting a signal of 10.000.000 degrees could be observed by Chandra if it lies at 50 light years or closer: the top left orange dot stands between the 100 and 10 lightyear green lines.

If the signal temperature is colder (10.000 degrees), then it is up to Gaia to see it, even if it lies much further away: the top right orange dot is much above the 100 lightyear blue line.


Take-home message: mirror star signals

In a mirror world theory, there exists a copy of all Standard Model particles and interactions. Whilst initially secluded from each other, the two copies can communicate by virtue of the properties of the visible and mirror electromagnetism.

As a consequence, mirror stars (the mirror counterpart of our visible stars) can emit X-rays that could be detected by existing space observatories, which could provide a way to detect clear signs of the mirror world (and thus of dark matter that is part of it).

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Comments 61


Very interesting theory with the universe mirrored on the "dark side".
Unfortunately, I don't quite understand the theory about X-rays. Shouldn't the X-rays also be mirrored and thus have a different energy potential? Simplified, in a negative energy level?

02.10.2019 16:56
3

Thanks for asking this! I omitted those details from the post in order to avoid having it too long :)

The X-rays are actually normal (and thus in principle visible) X-rays that can in fact be produced from two sources.

First, due to the mixing, a dark photon can be converted into a normal photon when interacting with the constituents of the visible nugget lying at the core of the mirror star. This interaction is made possible through the mixing (that bridges both worlds).

Secondly, the nugget can be heated by collisions with mirror atoms. Bremsstrahlung cooling then takes place and generate some X-rays.

Does it clarify?

02.10.2019 20:34
3

Thank you very much for your email and your explanation.
This helps a lot :-)
I know Bremsstrahlung as the x-ray source in radiography.

03.10.2019 16:53
0

Well... please be careful as I didn't send you any e-mail!

03.10.2019 19:12
1

Oh, I‘ve made a typo, I meant answer. I was writing some emails right before. Sorry 😊

03.10.2019 20:00
0

Ok then the case is closed (pfeew ;) ).

04.10.2019 07:01
1

Stupid question: Is there a second copy of us in the mirror world based on other physical laws???

02.10.2019 19:13
5

Ahaha! The question is not stupid at all. And I don't know the answer with 100% certainty..

The answer is however probably no, as the mirror world chemical elements are not occurring in the same proportion as in the visible world. For instance, the mirror world has much more helium than what is going on in our visible world. See here (if you have the strength to read it ;) ). Therefore, we may expect things to be entirely different.

Also note that gravity is the same in both worlds.

02.10.2019 20:19
5

As usual, the questions (and answers) are illuminating.

03.10.2019 02:58
3

Lol!

"Illuminating" is definitely the appropriate word when talking about photons and dark photons! I don't know whether this was on purpose, but this made my day (who started very badly with a lot of train issues).

03.10.2019 07:48
4

This reminds me of the simpson chapter where Homer enters a world of mirrors where his 3D version is found :p. It would be interesting to see a version of each of us in another dimension.

hahaha I don't know if this has anything to do with what you just said in your content...:P

03.10.2019 17:33
1

This has actually nothing to do with my content. But this was fun to read (I haven't seen this Simpson episode, but I can definitely visualise it :D )

03.10.2019 19:11
0

I'm not so clever as to make such a witty comment:) But I do have a question about photons. This may reveal (will reveal) my ignorance, but I keep going back to the same place in your piece with the same question:

Why do usual and dark photons mix? I understand how conversion may take place once they have met, but how and why do these elements from mirror worlds mix in the first place?

usual and dark photons mix. On very rare occasions, a visible photon can hence be converted into a dark photon, and vice versa.

Thank you in advance and apologizing for asking what may have an obvious answer...

03.10.2019 20:31
8

The short answer is: symmetries! I am however sure you are looking for something longer. So here it is. I will try to make it reasonably understandable. Let’s hope it works, because it is not trivial at all, at least for non particle physicists (so that you can already conclude that your question is by far not an easy one).

In the context of particle physics, we first start by postulating a few symmetries that will dictate how the fundamental interactions work. In the case of the model under consideration in this post, we thus have 6 symmetries in total: one for electromagnetism, one for the weak and one for the strong interactions, plus the three mirror counterparts.

The symmetries related to the two electromagnetisms are special: there are such that photon self-interactions must be forbidden (to match data). And of course, the same holds for the mirror counterpart by virtue of the definition of the mirror world.

From there, we can build the theory: anything that is allowed by the symmetries has to be there (and is actually predicted). The symmetries related to the dark/visible electromagnetisms allow the two photons to mix when they propagate. This can be seen as a dark photon turning into a visible one when it propagates, or vice versa. Another way to see this is as follows: mirror matter interacts with the dark photon only. However, since the dark photon can turn into a visible photon, mirror matter somehow also interact with the visible photon (though mixing, the interaction being somehow not direct). And again, the same holds for visible matter and the dark photon.

However, electromagnetism is known for more than a century. And very well known. Therefore, if visible photons could turn into dark photons, we should have already noticed something weird in data. And we haven’t. As a result, the mixing between the two photons is constrained to be of at most one part in a billion. It is thus damned small, so that any related phenomenon will be super rare, and thus hard to detect experimentally.

I hope this satisfies your curiosity! In any case, feel free to come back to me for more information or further clarifications.

04.10.2019 06:54
2

That was a wonderful answer! I do believe I understand:

electromagnetisms allow the two photons to mix when they propagate.

In theoretical particle physics, you follow the laws, and the laws allow this...predict this. However,

As a result, the mixing between the two photons is constrained to be of at most one part in a billion. It is thus damned small, so that any related phenomenon will be super rare, and thus hard to detect experimentally.

I had to read it a couple of times...not because the answer was dense but because, I had to :) But I believe I've got it. A very tiny, but satisfying moment of enlightenment :))

Thank you, @lemouth!

04.10.2019 16:57
7

Concerning the mixing, it cannot be zero. A zero means simply there must be a symmetry behind it. But data is the queen after all. So if data tells it's small, it's small.

One further question (without any real answer) which this could lead to is the following: How come it is so small? This is indeed very unnatural: we like parameters of order of 0.1-1.

The quick answer is that there must be some mechanism behind the entire setup that makes the mixing tiny. And this is where it starts to be tricky (and funny too)... Designing such a mechanism.

04.10.2019 22:07
0

Once again these topics are really strange and interesting at the same time.

For instance, the fact that we know about the other world and also measure some "signals" from there, but how can we get there to see what's really going on?
Or is this impossible?
You say that the chemical situation is different from our "level". How could life be organized there?
Or is life impossible in other dimensions thus we were never able to travel there?
Are these dimensions, therefore, more abstract rooms, we can't get into with our state of mind?
I know it's a pretty sci-fi-like comment by me.

Thanks for stimulating my mind in this way.

Best Chapper

04.10.2019 12:20
0

For instance, the fact that we know about the other world and also measure some "signals" from there, but how can we get there to see what's really going on?

Actually, we must say "we could know" instead of "we know". We have a way to probe the mirror world, but so far there is no sign of it in data. Consequently, this will constraint the theory. Inversely, if we have a signal of something, you can be sure there will be in no time hundreds of theoretical interpretation of it. Then we need time, more data and more global analyses (investigating many channels and signatures) to see which one of these theories could hold and which one is just wrong.

The un-famous 750 GeV excess of the LHC is a good example of this: 400 theory papers explaining an excess who disappeared after a year [fun fact, I only wrote one and I was claiming that either our knowledge of the strong interaction is wrong, or the excess is fake; I was right!] :)

Thanks for stimulating my mind in this way.

I am glad to read this! Have a nice week-end!

04.10.2019 22:12
1

One personal question: Do you think that the scenarios drawn in various sci-fi movies and literature (beaming, living in various worlds, intelligence of the universe...) could be reality???

05.10.2019 15:45
0

I do not think so personally, as these movies are generally flawed completely from the physics standpoint.

However, note that this has nothing to do with we is called "mirror world" here (except the name).

06.10.2019 08:15
1

Interesting, there are really many ways being studied about dark matter!

Yesterday, I saw someone talking about the fact that the hypothetical Planet 9 of our solar system would be a primordial black hole, beyond Neptune with the size of a tennis/baseball ball that remains from the early days of the universe, and that this could also explain the dark matter because it would be something common in the universe, even if for the moment none could be found yet.

This could also plausibly explain the odd orbits of “trans-Neptunian objects” as a hypothetical planet 9, since the planet 9, if it existed and given its distance from the sun, could only be a errant planet captured by our solar system.

It really seems that our time has nothing to be ashamed of compared to some others, as we seem to be starting to touch major discoveries with our fingertips!

03.10.2019 06:18
2

Yesterday, I saw someone talking about the fact that the hypothetical Planet 9 of our solar system would be a primordial black hole, beyond Neptune with the size of a tennis/baseball ball that remains from the early days of the universe, and that this could also explain the dark matter because it would be something common in the universe, even if for the moment none could be found yet.

Yes there was indeed a recent article studying this hypothesis.

The nice thing with our era is that we have a lot of issues here and there (both in data and at the theoretical level). The motivations to work on new phenomena is thus quite important, and the absence of guiding hints for nature forces us to explore all possibilities (we need to be pragmatic). This is exactly why I work in this field! :)

03.10.2019 09:10
2

Ah! Been waiting for this article. My imagination went wilder this time. I Imagined everything from mirror stars to mirror black holes. Though this also popped some curiosities in my head. They may sound a bit far fetched but I will list them anyway.

1st being if mirror starts have temperature like our starts, we can't detect them because mirror photons may not heat normal matter. But if a mirror star and a normal star collided would we notice any hear transfer at all (Though I know for hear transfer you need exchange of kinetic energy, which may not happen because mirror and conventional particles don't interact. But is there any possibility of it.

However, they do interact via gravity I assume. So when a star and mirror star are nearby pre collision they should create tides on surface of stars. Can we measure the tidal forces on far away visible stars? If say would it create something like random erratic dips in intensity of starlight. I mean can something like a tabby star which shows erractic 20℅ dip in light intensity be because of a mirror star around it.

Also, is there a possibility of binary star system with mirror and conventional star. In this case we should see a chaotic star movement without a binary partner to explain it, no?

Finally, say there are mirror white dawrfs. Do you think having more sensitive gravitational wave detector would be able to notice something of they see a mirror and non mirror white drawf interacting?

03.10.2019 07:42
7

I always deliver, but I usually don't put any deadline (because I know how busy I am :D ).

Thanks for this nice comment with so many remarks and questions. Let me dig into it. Note that I answer from the knowledge I have learned in reading the associated papers and that your questions lie a bit far from my zone of comfort. I however think that my answers make sense. In any case, feel free to object and continue the discussion!

1st being if mirror starts have temperature like our starts, we can't detect them because mirror photons may not heat normal matter. But if a mirror star and a normal star collided would we notice any hear transfer at all (Though I know for hear transfer you need exchange of kinetic energy, which may not happen because mirror and conventional particles don't interact. But is there any possibility of it.

There are two things in this question. First of all, mirror photon can heat normal matter due to mixing. The mixing being however extremely small, the occurence rate associated with this process is tiny. The mixing can be seen as follows: normal photon can very rarely interact with the mirror world, the rate being suppressed by the tiny mixing. Inversely, dark photons can very rarely interact with the visible world, the rate being again suppressed by the tiny mixing. Both those classes of events are thus possible, although they are super rare.

Secondly, mirror and visible stars interact both gravitationally so that their respective dynamics will influence each other. After all, this is the main motivation for dark matter. Taking the Milky Way as an example, some calculations have estimated that the local dark matter density could be comprised of 10-20% mirror stars. Those stars have however to be located in the dark matter halo surrounding the visible part of the galaxy, so that the collision probability with an ordinary star can probably be considered negligible. This latter sentence is however a guess as I haven't found any paper detailing any related calculation.

However, they do interact via gravity I assume. So when a star and mirror star are nearby pre collision they should create tides on surface of stars. Can we measure the tidal forces on far away visible stars? If say would it create something like random erratic dips in intensity of starlight. I mean can something like a tabby star which shows erractic 20℅ dip in light intensity be because of a mirror star around it.

I think this is answered above. One special case may be when two galaxies collide. In the case of the so-called bullet cluster, it was found that the dark matter was slowed but not stopped. This may reinforce the fact that the star-collision probability is likely to be negligible with respect to any other phenomena occurring in this case (and if it is not the case, this yields constraints on the model). Again, I didn't find any paper on that...

Also, is there a possibility of binary star system with mirror and conventional star. In this case we should see a chaotic star movement without a binary partner to explain it, no?

I do not think so. See above.

Finally, say there are mirror white dawrfs. Do you think having more sensitive gravitational wave detector would be able to notice something of they see a mirror and non mirror white drawf interacting?

In some case, a mirror star may actually look like a white dwarf (in some specific temperature/mixing setups), as shown in the last figure of my post (the blue filled ellipse correspond to a standard white dwarf signal). Somehow, the X-ray mirror star signal can be sometimes seen as a fainted white dwarf signal.

I finally do not think gravitational waves can help here as we need a quadrupole moment to generate such waves (which cannot be done with a single star). I think X-rays are our best chances in both cases, but it is not that easy (as emphasised in the plot).


I refer to this long review for more information (you can also ask me more as it is a really long document).

03.10.2019 08:53
2

Science meets science fiction meets fantasy. Crazy shit, and a great read, thanks!

03.10.2019 12:22
1

Science fiction is never really far from science. A good proof is Star Trek: What was science fiction back in the days is now real :D

03.10.2019 19:32
0

😆 Isn't this mental? I'm well into particle physics now!

04.10.2019 14:01
0

We should write a publication together soon! :D

04.10.2019 22:13
1

Very Interesting idea.
Is this (https://arxiv.org/abs/1909.04071) your paper ?
$trdo

03.10.2019 15:58
2

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03.10.2019 15:58
0

This is actually not my paper. I am reading many papers every week, and one of them always finishes as a blog post. Of course, when I write a paper myself, my paper is automatically selected and ends on my blog, as I really enjoy chatting about my own research.

FYI, the last time I discussed my own paper was a couple of months ago, here (this addresses computer simulations at high-energy particle colliders).

03.10.2019 19:30
0

That's great. Are you Benjamin Fuks ? I too enjoy chatting about my research.

03.10.2019 19:46
0

Professor Benjamin Fuks ? Nice to talk to you. I am a Ph. D student at Indian Institute of Science.

03.10.2019 19:55
0

Yes this is myself. Nice to meet you! ^^

03.10.2019 20:22
0

Hi @gijoge ... Nice to know that you are from IISc. You should join our steemstem discord server (link: https://discord.gg/DmJqdXh). I am from IMSc, Chennai. And another popular steemian @scienceblocks is from NCBS.

06.10.2019 15:32
1

Hi @dexterdev Nice to know that you are from IMSc. I am also a malayali. Happy to see some other people interested in science in steem from india. Again thanks for mentioning about you and @scienceblocks. You are Ph.D or Post Doc ?

06.10.2019 16:04
1

I am a PhD student. There are other Keralites too here. @bobinson @sathyasankar @elsaenroute Do come to the steemstem discord server :)

06.10.2019 16:07
0

Thanks bro for that piece of information. I am already in discord.

06.10.2019 16:15
1

okay

06.10.2019 16:17
0

You do MD simulations ? I see some overlap in our research interests. I may need your help sometime.

06.10.2019 16:46
0

Yes I do MD simulation. We can talk on discord.

06.10.2019 16:53
0

sure. we will talk sometime.

06.10.2019 16:55
0

Bro.. I'm from Kerala too. Why you get too much downvotes?

08.10.2019 13:18
0

Hi @sathyasankar
keralathil evada. Nice to meet you.
they are downvoting because all the videos are shared from youtube. I will still do the same. let them downvote. I don't care.

08.10.2019 14:11
0

Idukkiyilaa enter veedu... Ippa Biharil work cheyyunnu. The community needs original contents. So it is better not to share contents that you do not own.

08.10.2019 14:22
0

Original contents are better. But i don't care about those things. I will share whatever good science i see anywhere. Anyone can downvote. Let them do.

08.10.2019 14:35
0

Then, decline payout or set @null to beneficiary to burn your rewards.

08.10.2019 15:35
2

Thanks for your suggestion. But i don't take that. You can also downvote it.

08.10.2019 15:42
0

That's not how you share around here.

10.10.2019 13:23
1

Do whatever you want to do

10.10.2019 13:28
0

Hi @gijoge. I am doing my PhD in biology. Which dept at IISc?

06.10.2019 18:57
0

Hi @scienceblocks. I am about to finish my Ph.D here. I am working in NMR Research Centre. We could see sometime in NCBS or IISc.

06.10.2019 19:16
0

Nice :)

08.10.2019 21:16
0



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03.10.2019 19:33
1

Interesting view of the universe.

But where is God?

Is God part of our universe or of the mirrow world?

Or is he part of both worlds?

And if God is part of our universe - is there an "Anti-God" - the devil existing in the mirror world?

If so, isn´t it better to get no contact in any kind to the dark matter of your proposed mirrorworld?

Best regards.

05.10.2019 21:35
3

Mmhhh... The eternal question of religion and science. That is a complicated debate as we enter the territory of the personal beliefs. And I will skip it and answer only from a scientific standpoint.

Here, I would say what is going on with God (or gods or anything that could play this role, depending on what one believes in) is completely disconnected from the topic: I am discussing some ways to understand the mechanism behind the functioning of the universe at the fundamental level: what is the nature of the building blocks of matter and how they interact.

By the way, this theory is not something I have proposed myself (other great physicists did). It is for now only theoretical: it may exist (and then we know how to look for it) or it may not exist. As it may exist, we need to be pragmatic and test it (to make sure not any interesting phenomenon is missed in data).

However, at the end of the day, we are discussing elementary particles and there is no real concern about the existence of mirror beings, mirror animals or even mirror gods. The abundance of the mirror chemical species being different from what they are in our world, I doubt mirror-us would exist (see my answer to @chappertron a bit further above in this post).

06.10.2019 14:43
2

Thanks for your detailed reply and point of view.

I am not talking about religion as way of beliefs of human beings or a practice to supress development of the individuals, when I am mentioning God I refering more to the positive vibrations of the universe - which are some kind of energy.

In contrast to these positive vibrations of physics and energy, I think that dark matter is some kind of negative vibrations which we shouldn´t try to detect.

If God is existing - and I think it is existing as a natural law of Love which has build up the all the rules of the universe - than is one rule which we should respect in order to survive as human kind - and this rule is not to detect in any kind the source of dark energy and dark matter, if we do not want to destroy the universe in which we are living.

Einstein said: "God doesn´t play dice!"

I think there is some kind of energy in the universe behind our fourdimensional way of thinking - beyond time in higher dimensions.

We can not leave as human beings the three dimensions without material damage at our own.

But we can propably describe energy transfer from multipolar dimensions and the effects behind the event horizon God created beyond the three-dimensional world.

Maybe we can look behind this event horizon as soon as we has stopped war on this planet and startet to love the human family.

I think the first step to find out what is exsting behind the event horizon of our universe to focus our energy on the development of peace and freedom in our existing world.

Without peace and freedom the world is in danger - especially if the origin of dark matter should be found and set free.

So I think God or who ever has a plan - and this plan and timetable says that humand kind at present is not ready to deal or handle with dark energy in any kind.

The mirror of darkness is the answer on our existence in the present universe.

The curtain of knowledge will not open until we are ready to love one another instead of killing one another.

This will be the first step to solve the secrets of the universe.

Best regards.

SEND with LOVE.

Peace

07.10.2019 00:38
0

Then I would need some better definition of those ‘positive and negative vibrations’, which sounds very vague to me. On scientific grounds, I actually do not understand their meaning at all. While a vibration is well defined, I would not attach to them the positive or negative qualificatives as this does not mean much from the physics standpoint. Of course, one can be more philosophical and we then enter a different debate. Which is what your comment is actually doing :)

To emphasise one thing: what we call dark matter is dark because it does not interact electromagnetically. There is nothing negative in this. It is just a word that means what I have just said: dark matter is transparent to the particle of light, i.e. the photons (or electromagnetism). This contrasts with the usage of this word in your comment so that we actually discuss different things.

08.10.2019 21:14
0

Why would God be bound inside His creation? You don't seek the artist in his every painting. The architect is rarely in the buildings he designed.

08.10.2019 17:17
0

There is no scientific proof of the existence of any god. Okay, similarly there is no proof of its non-existence as well. Which is why science and religion are somehow not mutually exclusive. But this is not the topic of my post :)

08.10.2019 21:15
0

If God exists outside of, separate from, and independent of His creation, it is a matter outside the realm of scientific inquiry. It is a very weak, and indeed fallacious, argument to demand that a negative assertion be disproven. I don't think there is any inherent conflict between science and religion. The people who made the first forays into the scientific revolution were often religiously motivated.

09.10.2019 01:30
0