Mirror Matter (also known as Shadow Matter or Alice Matter) is a hypothetical type of Dark Matter. It's made up of subatomic particles that are a "mirrored" reflection of the existing particles of our mundane universe. As a result there's only two ways Mirror Matter can interact with normal matter.
- Gravity - Mirror Matter distorts Space Time just like a similar mass of normal matter. This is the primary way mirror matter can be detected and interact with mundane matter.
- Photon Mixing - Mirror Photons can sometimes get swapped with normal photons. Since one photon goes away at the same time as another appears, this might seem more like a mundane photon spontaneously changed wavelength or direction.
In all other ways, Mirror Matter is intangible and invisible to normal matter. You can look through it without seeing it, pass through it without feeling it, etc. It isn't affected by magnetism or radiation, can't form bonds with mundane matter, and effectively doesn't exist, except for it's gravitational effects and occasional rare photon mixing.
Game and Story Use
- A mirror star or planet would make for an interesting negative space wedgie, swirly energy thingy or unexplained phenomena. It'd have huge gravity (and possibly persistent crazy photon emissions), but otherwise just wouldn't be there. It'd be dangerous, though.
- You might lack the Delta V to escape it's gravity well, or you might get crushed by the pressure of it.
- Even if you compensate or avoid those dangers, there might be health or tech issues if a some of the mundane photons of the lights aboard your spacecraft started swapping out for high-energy x-ray or gamma-ray photons from a mirror pulsar or supernova.
- The name, at least, evokes several concepts that it actually has no link to, but that shouldn't stand in the way of a good sci-fi plotline. As long as you know you're playing fast and loose with science, and don't have players that are going to balk at it, do whatever you wish…
- Mirror Matter technically doesn't have anything to do with a Mirror Universe, Parallel Universe, or Counter Earth. These concepts seem made to go together. Perhaps scientists made of mirror matter are currently at work on the technology to communicate with, explore, destroy, or convert our matter.
- Despite the name "Shadow Matter", this stuff doesn't have anything to do with Shadow People or Shadow Life, either. But wouldn't it be cool if life made of Shadow Matter is already here on Earth?
- An object, particularly a large one like a star or planet, might have both mirror matter and normal matter in the same space. Say, if the gravity well of a large mundane planet started accumulating mirror matter. It would fall toward the center of that planet, and slowly acrete into a mirror planet. As this happened, the gravity of the original planet would get stronger and stronger. Eventually it might be enough gravity that the planet effectively collapses - or becomes a brown dwarf with only half the usual mass.