Exotic Matter

Joker · Mar 17, 2016

I'm trying to wrap my head around exotic matter. As far as I understand it, this hypothetical matter is partly used to make work the math that would make wormholes stable.

My question is could this be normal looking matter with strange properties? If, instead of attracting like regular matter, it repels, would it have any noticeable effect on its surroundings?
Let's say you have a building made of the stuff that had as much mass as a building of regular matter; Would it affect its environment in any way that was apparent to people going inside or walking around it?

Umbran · Mar 17, 2016

"Exotic matter" is any theoretical matter that has properties we don't see in the normal stuff. It is the more technical term for "unobtanium".

What it would look like would depend on exactly which properties the particular stuff in question has.

For example, let us consider a form of exotic matter that repels gravitationally, but has standard electromagnetic properties.

Your first question is - how do you find this stuff? Your planet is brought together by gravitational attraction, but this stuff is repelled. So, unless it was already bound in a molecule or other hunk of normal matter, it drifts *away* from the Sun as it and the planets form. But, if it has normal electromagnetic properties, it can still form chemical bonds. So, you can imagine finding it bound up with normal matter, and harvesting it, I suppose.

Assume, for the moment, that you did get a supply of this stuff. Well, it has mass (so, it takes force to move it around), but is has negative weight. What does that mean? Well if you made a skyscraper out of it, people standing next to it wouldn't feel anything much - normal skyscrapers don't *pull* on you much, so this one wouldn't *push* on you much either. However, the push between it an the Earth is another story....

This structure has negative weight. Instead of resting on the ground with its full weight, it is *pulling away* from the ground with its full weight. The Empire State Building weighs 365,000 tons or so. That means the Exotic State Building will be pulling away from the Earth with a force of 365,000 tons. What, pray tell, are you binding it to the ground with? This sucker is going to rocket away from the ground, with a thrust equivalent to over 1700 Space Shuttle Main Engines. The building has much more mass that the Shuttle, so it may not take off as fast, but it will be *inexorable*. Good luck holding it down.

tomBitonti · Mar 17, 2016

It would seem that if any such matter exists, it might as well as what seems to be normal matter, just with one of the properties changed. Except for a very special case, an antimatter moon would be the same as our moon, to anti-matter people.

The exotic properties would cause a lot of problems, e.g., a repulsive force makes matter want move away from normal matter. (What Umbran describes.)

I like the idea of matter which has a different coupling between inertial and gravitational mass. A big hunk of matter which had a much smaller gravitational mass. Say, if you attached normal matter to matter in a parallel space (that's magic), giving the ensemble the inertia of the combined mass but a gravitational interaction only base on the matter in our universe. That would be an interesting MacGuffin for a Sci-Fi RPG.

Thx!
TomB

Janx · Mar 17, 2016

Joker said:
I'm trying to wrap my head around exotic matter. As far as I understand it, this hypothetical matter is partly used to make work the math that would make wormholes stable.

Note: I know nothing about physics. don't take any of my ideas seriously.

One problem I have with this usage of Exotic Matter, is having it be a place holder in math for mythical things like worm holes. It's one thing to see that the math for the universe is off when we account for all visible matter, but it resolves if we insert "Dark Matter" to account for it. The implication is that we need to find a way to confirm if Dark Matter exists to then finish solving the formula. That's worlds different from "worm holes have never been observed and thus may not exist, but I can make up some math and magic matter that would allow them to exist."

The difference between the Universe and Dark Matter is that we know the Universe exists, and Dark Matter as a placeholder solves an equation. We don't actually know that worm holes exist, so using exotic matter as a placeholder to solve worm hole math seems like a double-dependency on placeholders.

Umbran · Mar 17, 2016

Janx said:
One problem I have with this usage of Exotic Matter, is having it be a place holder in math for mythical things like worm holes.

Okay, well, here's the thing. Physicists don't actually use it that way.

In the case of wormholes, it goes like this: Einsteinian General Relativity allows for wormholes to exist. However, if we subject the result to perturbations (small changes - like say a star goes by in the vicinity, changing the local space by a small amount) we find that the wormhole should collapse. Wormholes are found to be not stable to even very small perturbations, like "a butterfly flapping its wings in the China Sea" is big enough to make the thing collapse.

So, some folks tried to figure out what would be necessary to keep a wormhole open. The answer seems to be that you need to create a region of negative energy density around the thing - the exact shape can vary somewhat, as I recall. Now, we know how to make very small regions with very small amounts of negative energy density. But this would be of a different order entirely. As a practical matter, we posit that we'd need some material we currently don't have to manage it - not only dont we have this material, but we've no observatiosn that suggest it exists. Thus, it is "exotic".

The argument that you need exotic matter to keep a wormhole open is typically an argument *against* stable wormholes existing.

There are a couple of things that we expect do actually exist, that we have next to no chance of getting our hands on, that are also lumped in with "exotic matter". Neutronium - the stuff that neutron stars are made of, very likely exists (we have observed objects that have all the properties we'd expect a neutron star to have), but getting it? How? The stuff is down in a friggin' neutron star!

There's also "degenerate matter", which you find in the cores of large stars, or in their white dwarf remnants, in which the main source of pressure is not the temperature of particles that bang against each other, but the quantum mechanical Pauli Exclusion Principle, is also considered exotic, but is not really possible to get.

Tonguez · Mar 17, 2016

Umbran said:
This structure has negative weight. Instead of resting on the ground with its full weight, it is *pulling away* from the ground with its full weight. The Empire State Building weighs 365,000 tons or so. That means the Exotic State Building will be pulling away from the Earth with a force of 365,000 tons. What, pray tell, are you binding it to the ground with? This sucker is going to rocket away from the ground, with a thrust equivalent to over 1700 Space Shuttle Main Engines. The building has much more mass that the Shuttle, so it may not take off as fast, but it will be *inexorable*. Good luck holding it down.

ah so thats what happened to Sokovia!

Umbran · Mar 17, 2016

Tonguez said:
ah so thats what happened to Sokovia!

I suppose Ultron's machine that looked like a giant set of repulsor lift engines might instead have been infusing the land with exotic matter. Sure, we can go with that.

Especially since Agent Carter has introduces "Zero Matter", which is the best implementation of Marvel Universe "Darkforce" I could ever have hoped for....

freyar · Mar 18, 2016

Umbran said:
Okay, well, here's the thing. Physicists don't actually use it that way.

In the case of wormholes, it goes like this: Einsteinian General Relativity allows for wormholes to exist. However, if we subject the result to perturbations (small changes - like say a star goes by in the vicinity, changing the local space by a small amount) we find that the wormhole should collapse. Wormholes are found to be not stable to even very small perturbations, like "a butterfly flapping its wings in the China Sea" is big enough to make the thing collapse.

So, some folks tried to figure out what would be necessary to keep a wormhole open. The answer seems to be that you need to create a region of negative energy density around the thing - the exact shape can vary somewhat, as I recall. Now, we know how to make very small regions with very small amounts of negative energy density. But this would be of a different order entirely. As a practical matter, we posit that we'd need some material we currently don't have to manage it - not only dont we have this material, but we've no observatiosn that suggest it exists. Thus, it is "exotic".

The argument that you need exotic matter to keep a wormhole open is typically an argument *against* stable wormholes existing.

Yes, from looking at the original papers, I think Morris and Thorne kind of approached it as a game or challenge --- what does it take to keep a wormhole open, and does that make sense? There is something of a school of thought in some areas of physics that you should do this kind of thing, that is, postulate a weird behavior that might seem counterintuitive, see what it would take to get it, and then argue whether that's actually possible. It's somewhat popular in one branch of cosmology. I don't personally find it terribly productive, since it seems like it spends a lot of time arguing about whether something that's probably impossible can exist or not.

More later...

Umbran · Mar 18, 2016

freyar said:
I don't personally find it terribly productive...

I expect it is as productive as any other form of play - which means the activity probably isn't *directly* productive, but has lots of good results that should not be discounted.

freyar · Mar 18, 2016

Umbran said:
I expect it is as productive as any other form of play - which means the activity probably isn't *directly* productive, but has lots of good results that should not be discounted.

It's possible, though, as a scientist, I have to make my best bet about what will actually tell us something interesting about the universe, whether directly or indirectly. My bet is not on models that at least appear mathematically and physically inconsistent before you add lots of epicycles, that's all.