My story involves reference to another universe which is never actually visited during my story. This other universe has very different physics e.g. time works differently, matter and energy related differently to each other.

Within my story there is some matter from this universe that has come into the setting of the story (which is basically our universe)

My question is - is there any theoretical guidance how this matter may behave? Would it be possible that it "retains" the physics from it's universe of origin etc? Or am I free to totally make up how it acts and effects and interacts with our universe?

(I'm hesitant about using a 'science based' tag because I'm not sure if there is any science for answers to be based on, but I guess that's why I'm asking)

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    $\begingroup$ You're asking us to postulate how an imaginary substance from an imaginary universe would behave without identifying in every possible way the physics of the imaginary universe. The only viable answer is, "it'll behave the way you want it to behave." Perhaps there's a mathematical hypothesis that suggests an electron from A would behave (differently/or-not) in B, but I doubt it - we have no empirical evidence that other universes even exist. I'm not convinced this question can be answered in any better way. $\endgroup$
    – JBH
    Commented Jun 21, 2020 at 18:04
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    $\begingroup$ There is some story precedence in Neal Stephenson's "Anathem" for that (although it does not answer your question, hence I write this as a comment). In that story, there is "newmatter": Matter that's been "imported" from parallel universes with slightly different physical constants. Here's an excerpt that explains that "newmatter" a bit: anathem.fandom.com/wiki/Newmatter $\endgroup$
    – orithena
    Commented Jun 22, 2020 at 17:39

3 Answers 3



Here are two principles:

(1) The universe is very finely tuned. There are a bunch of numbers programmed into the laws of physics, like the speed of light, masses and charges of the fundamental particles, Plank's constant, Newton's constant, and the fine structure constant. The fine structure constant for example is related to how strong of a pull charges exert on each other.

You can imagine tweaking any of these, and all that happens is that everything gets a bit heavier, or maybe magnets get a bit stronger or weaker. The hard part is tweaking things like this makes atoms either unstable or makes them collapse entirely. So you end up with a universe with no complex matter. Just a bunch of high energy particles whizzing off everywhere.

(2) There is a finite list of "allowed particles". If you shoot a bunch of lazer beans into each other then you get a large concentration of energy at a point. The universe has to decide what to do with this energy. Some of it will get turned into particles and some will get turned into the kinetic energy of those particles. If you shoot enough lazers you might get some electrons popping out. If you shoot even more you might get some protons or Higgs bosons or some other heavier particles. But you cannot shoot a small amount of lazers to generate half an electron.

Now its concievable there is a different universe with different constants that makes complicated matter possible but the rules for how it behaves and list of allowed particles is different. They have atoms but their atoms are different.

I imagine someone has a chunk of matter matter from the other universe in a time suspension field and loads of scientists looking at it going "this isn't allowed". Then someone accidentally turns off the field; the rules for our universe kick in, realize the particles in the contained are not allowed. But the particles still have energy due to having mass and that whole $e=mc^2$ mumbo jumbo that hardly anyone every talks about. Since the energy has to go somewhere it gets converted into a bunch of smaller allowed particles that go whizzing off in all directions. Boom.

Would it be possible that it "retains" the physics from it's universe of origin etc?

We like to think there is a big proton field that underlies all of time and space, and a proton is just a little wibbly wobbly bump in that field. Likewise there is an electron field and photon field, and so on for all the fundamantal particles.

If the second universe has an electron field but that field is a bit slower so they exert less of a force on each other, we can imagine the second electron field wobblying into the first one and producing ripples (particles). Then the particles are in our field and would obey our laws.

Imagine some sound waves are moving through water (where they move slowly) and then travel into a solid (where they move faster). The waves were created in the water perhaps but they don't remember that fact, and as long as they are in the solid they follow the physics there.

Now if the second universe has some other X field that we don't have then it's hard to imagine how some X particles could even exist in our universe at all. You could imagine their X field bangs against our photon field and creates a bunch of photons. But I don't think that's exactly what you're looking for.

Edit: Or maybe we DO have an X field but for some reason there is no way to actually stir it up and create X particles? We can only get them from the other universe. This might be your best bet. . . I am not aware of anything in physics that specifically FORBIDS an extra field that is there but doesn't actually do anything.

Or am I free to totally make up how it acts and effects and interacts with our universe?

I'd say you are totally free to make up whatever happens at the boundary where the matter passes from one universe into another. But if you start saying the alien matter follows different rules to ours, once it's inside our universe, then you'll get loads of physics curmudegons like myself who cluck their tongues, stroke their beards, and talk about "What's to be done with this Homer Simpson?"!

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    $\begingroup$ It's "Laser", not "Lazer." $\endgroup$
    – NomadMaker
    Commented Jun 22, 2020 at 6:42
  • $\begingroup$ This is a great answer. Thank you. It gives me some good theoretical framework to work with, especially the X field concept. $\endgroup$ Commented Jun 22, 2020 at 19:37
  • $\begingroup$ Is "lazer beans" a typo? $\endgroup$ Commented Jun 22, 2020 at 19:58
  • $\begingroup$ @MadPhysicist: Yep. Should be "laser beans" thanks. $\endgroup$
    – Daron
    Commented Jun 22, 2020 at 20:22
  • $\begingroup$ @Daron. "n" -> "m"? $\endgroup$ Commented Jun 22, 2020 at 20:57

The short answer is yes, it's possible to write hard-science story with that assumption. I remember at least one story where scientist in our world once discover in its lab a scheme to build generator. The generator produces energy from difference between two universes law - strong nuclear force. There are almost no interaction between worlds.
(The story is "The Gods Themselves" by Isaac Asimov. Thanks to Stephen!)

  • $\begingroup$ @JBH I understand it but I suppose it's too big for comment $\endgroup$
    – ADS
    Commented Jun 21, 2020 at 18:08
  • $\begingroup$ @JBH I edited my answer a bit in that way it become more answer than a comment. If you feel there are things which improve it please let me know. If you think nothing helps and I should move it to comment then just say it and I do that. $\endgroup$
    – ADS
    Commented Jun 21, 2020 at 18:32
  • 3
    $\begingroup$ The novel was by Isaac Asimov and was called "The Gods Themselves" unless I am mistaken. $\endgroup$ Commented Jun 21, 2020 at 19:35
  • $\begingroup$ @StephenG yeah, you are right, thank you! $\endgroup$
    – ADS
    Commented Jun 21, 2020 at 19:43
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    $\begingroup$ Better. Thank you! $\endgroup$
    – JBH
    Commented Jun 21, 2020 at 20:20

Strange matter.

Strange matter is theoretically possible. It is matter containing strange quarks. There is none around here so if it exists, another universe would be a fine place for it.


Ordinary matter, also referred to as atomic matter, is composed of atoms, with nearly all matter concentrated in the atomic nuclei. The nuclear matter is a liquid composed of neutrons and protons, and they are themselves composed of up and down quarks. Quark matter is a condensed form of matter composed entirely of quarks. If quark matter contains strange quarks, it is often called strange matter (or strange quark matter), and when quark matter does not contain strange quarks, it is sometimes referred to as non-strange quark matter.

It is probably good there is none around. Some visions of strange matter have it being able to "convert" normal matter to strange matter. Sort of like a matter zombie epidemic.


How could strange matter be dangerous? Under special circumstances, it "eats" other matter. In order for this to happen, the strange matter has to be more stable than the matter it meets and not repel it. If those conditions are met, the other matter will "want" to convert to strange matter, and contact between the two will get things going. The result would be an ever-growing ball of strange matter, burning through matter like a fireball.

Of course if you are messing with physics you can have anything you want. Which can be too liberating, and risks lapsing into lameness. Using strange matter keeps it weird and otherworldly but lets you use rules that thoughtful people have thought out for how the stuff will behave.

There is quite a bit on the WB stack about strange matter from the speculative fiction standpoint. https://worldbuilding.stackexchange.com/search?q=%22strange+matter%22

  • $\begingroup$ Thanks, I'm not sure these strange quarks are quite what I'm after but I might borrow bits from them for plot particles. $\endgroup$ Commented Jun 22, 2020 at 19:39

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