Lightknight said:
CrystalShadow said:
Lightknight said:
So why don't we have the opposite of black holes here? What would an anti-black hole even look like? Wouldn't gravity in that universe then have to be repellent for this to work? Surely the physics of that universe would have to be pretty different.
I would be interesting if it were rather another half of our universe that we just aren't aware of yet. Like another polar side that repels mass while we pull mass in ours.
There's a common conjecture that a white hole could exist somewhere in the universe.
That's the thing with some of this stuff. It's mathematically possible, but we've found no evidence of actual examples.
Anti-gravity is possible (and trivial in fact) in a mathematical sense. But we have no evidence of anything with anti-gravity properties actually existing in the universe.
Something with negative mass can also exist, mathematically. Doesn't make a huge amount of sense what something like that would be like, but the numbers check out as well as anything.
Of course, the mathematics also says there's no reason time can't run backwards...
Just doesn't seem to happen though. (Or if it does we can't perceive the consequences)
It seems like if a white hole existed that we would be pretty darn well aware of it. Wouldn't it take the form of a drastically different galaxy? Also, wouldn't the white hole have to be repellent rather than attractive?
You'd think so, but it depends a lot on what the exact properties of a white hole are, and where you'd find one.
And yes, it almost certainly would repel, rather than attract. (mathematically, it has negative gravity, and probably also negative mass)
There's several points to note though. While a white hole makes sense mathematically, there's a bit of a question as to how one would form in the first place.
And since it is basically an anti-gravity singularity, it would have an event horizon (just like a black hole does), only for a white hole it's the distance at which it's impossible for anything to get closer.
The nature of a white hole would imply that if there is any ordinary matter involved, the white hole would evaporate and stop existing quite quickly.
(it repels matter. If it were made of matter, it would rapidly repel it's own internal contents away from itself)
Are there any running theories that our universe is actually a sort of half-universe that is pair-bonded with another half-universe where these objects exist and properties exist? That would be truly fascinating if so. But I assume that model would basically eventually result in everything that started over here going over there. Hell, maybe we're just one epic hourglass where the stars are grains of sands and the black holes are all the narrow neck connecting the bulbs...
I can't think of any. Brane theory has a lot to say about parallel realities, but nothing of that kind.
(Brane theory is closely related to string theory. And string theory involves a lot of weird quirks, amongst others, requiring the existence of either 11 or 26 dimensions.)
There's also the holographic theory. Which actually derives somewhat from black holes.
It states several things. Firstly that information is stored on the boundary, rather than the volume of things. (like how an image is stored in a physical object when you make a hologram, hence the name).
One of the peculiar implications is that the universe may actually be 2 dimensional.
However, on closer inspection it more so implies that it may not be very meaningful to say the universe has any specific number of dimensions.
It basically states that a universe with n dimensions can also be described identically as a universe with M dimensions but a somewhat different (but equivalent) set of rules.
Since they are interchangeable, it suggests you can describe the universe as 2 dimensional, 3 dimensional, 4 dimensional or whatever, and still come up with a set of rules that works correctly, so perhaps the underlying reality doesn't have any specific number of dimensions to it, and that is entirely a result of the way we like to think about it, rather than a fundamental quality of reality.
Physics can get rather weird when you start looking at all the cutting edge theories and stuff that has a reasonable chance of being true, but hasn't quite been verified properly against anything yet.
