Basic Information
A White Hole is a theoretical astronomical phenomenon that, if it exists, would be the inverse of a black hole. As you're probably aware, a black hole is a singularity that you can't see because it has so much gravity that not even light can escape it. Anything that passes within its event horizon disappears forever.
A white hole is like that, except instead of things (and light) falling into it, they can only fall out of it. Nothing can get closer than its event horizon. Instead, matter and light just keep moving away infinitely from it. The name is a little deceptive: it's not really white in the same way a black hole isn't really black. It's invisible. Light never gets to it, so it can't bounce off and hit your eye and reveal anything about it. If you shoot a laser at a white hole, the light will bend and veer off. (Matter and energy would be falling out of it, though, so the light it emits itself would actually be visible… so maybe it would be white.)
It's a pretty crazy idea, but the same math that explains black holes and spacetime also suggests white holes are possible. In fact, one way to interpret the math of the Einstein field equations is that the existence of a black hole requires the existence of a corresponding white hole. The black hole exists eternally in the future, and the interconnected white hole exists eternally in the past.
Now, if you think about it a bit, a thing you can't see, and can't approach, and are constantly moving away from kind of sounds a bit like our relationship to the big bang. We can't see the start of the universe, we can't approach it, and we are constantly moving further away from it in two ways: time and space. The universe is constantly expanding, all galaxies getting farther and farther away from each other over time. For this reason, one theory about a white hole is that every black hole creates it's own universe, centered on a corresponding white hole, which is the big bang of that new universe. Everything that falls into any given black hole here in our galaxy is crushed and transformed and expelled as energy in the big bang of a universe that is made up entirely from the stuff that fell into that particular black hole. It implies a sort of Russian nesting dolls/fractal/tree of life kind of relationship for parallel universes. Each universe sprouts infinite smaller universes from its many black holes. This is sometimes called the fecund universes concept. So that has cool ramifications along the lines of many-worlds interpretation of quantum mechanics. If we could find a way to enter a black hole without being destroyed, we could take a one-way journey to a new universe at the moment of its creation.
Another possibility is that a white whole might exist very briefly, before collapsing in on themselves and become a black hole. It's possible some of the gamma ray bursts (or other brief but extremely energetic phenomena) that happen in space could be caused by short-lived white holes. This was actually proposed as a possible explanation for one brief heavenly flash that was detected for 102 seconds in the 2006.
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Game and Story Use
- The concept of a white hole be a useful bit of technojargon for use when executing a hand wave to "explain" the weird tech of your system, such as an FTL drive or time machine.
- The notion of a one-way ticket to a new universe could make for some fun dimension-hopping exploits. You can get someplace new to explore, but you can't ever go home again.
- What if more than one white-hole can exist in our universe at a time, and that's not actually the same thing as the big bang? Well, you could have some sort of unknown phenomenon or negative space wedgie that bends space and pushes you away from a place.
- Instead of being invisible, maybe (especially in a space opera or a comedy setting that doesn't take its scientific accuracy too seriously) it would actually be white, emit light, and look from a distance like a white star.
- Or it might look like a gamma ray burst, fast radio burst, supernova or other huge explosion in space. That would be pretty devastating if it happened near your world. So you could use it for a space disaster, space weather, navigational hazard or other plot device. Afterwards, it might leave any number of strange phenomena, objects, or elements that were ejected from the brief whitehole explosion.
- The PCs are exploring the frontiers of space, and attempt to enter the system of an unusually intense white dwarf, but as they chart a course towards it, they can't seem to get any closer. They flail against it, but space keeps folding or stretching and they can't cross the gap. So they decide this must be a white hole, and send a message back home updating everyone, and make arrangements for some other science vessel to NPCs to come observe it so the PCs can get back to more adventurous stuff… but then that boat of NPCs goes missing, or reports some development back to the PCs that suggests maybe it's not a white hole at all. Maybe it's a sophisticated precursor artifact or planetary defense system that is sort of a combination of cloaking device and repulsing tractor beam. Something is actually in that system we can't get to, and it' trying to remain hidden! Now that's a mystery the players are going to want to investigate. The GM will of course need to come up with some way for the PCs to slip past the device so the plot doesn't stall out, but it could be interesting.