Opposite of Density

Despite the obvious difficulty in seeing black holes (i.e., they're black against a more-or-less black background) some likely ones have been found. There is very strong evidence that there is a large BH at the center of our galaxy. It is believed that most large galaxies have BHs at their centers. (BHs are found because the stuff falling into a BH emits a lot of radiation. From these emissions the presence of the BH is deduced.)

But, no white holes have been found. For a while it was thought that quasars were white holes, but that idea was eventually discarded.

So if we don't see white holes -- which you'd think would be a lot easier to find than black holes -- then there are probably no black holes in neighboring universes. (Black holes there that show-up as white holes here.) Which probably means there are no neighboring universes.

PS: I think the opposite of density is smartsity.

To be truly opposite,the White Hole would be dispersing the matter over a very large area,rather than a concentrated point,as in a black hole.The hole would not be "white" per se,but more like a spray nozzle with an infinite(or nearly)fan out pattern in multiple dimensions.It would not be visible as a point from our perspective, but strings(or quantum bits) would be seen to come from "nowhere" into our universe.With the black hole on one side, and the white hole on the other,an hourglass shape would form, sort of, but the smallest point would be nearly infinitely small, and immediately fan out into all dimensions. Imagine a universe where the speed of light is the minimum speed allowed.Anything slower would drop out into a slower dimension.(Ours?).Imagine a checkerboard pattern with C being a 45 degree diagonal line across each square.Anything at C or below would be our universe, anything above would be another.It might be possible to cross from like universes below or above the line, but not across the line.These checker board squares would touch at the corners, where there should be a very small but definite theoretical access point.Perhaps there are wormholes there.

Or have I had too much Scotch to drink? Or maybe the cigar smoke has deprived my brain of oxygen.Either way, I am sleepy now and will be back later.Cat nap time.

Addendum to my previous post:

I was not very clear with my squares illustration.What I meant was to construct a graph,with X Y coordinates, with X axis in 1 second of time, and the Y axis in 300,00 km.C will then be a 45 degree line across the "square".The other sides of the square are other similar dimensions, with C as maximum, and minimum speeds. Imagine these squares going on forever.

As one can clearly see,you would have to travel thru time to leave our universal boundaries.

Hope this clarifies it somewhat.

HTRN

I always thought obesity was the opposite of density.

Hi HTRN.

Yes, the volume of space and the energy density of that space are reciprocal functions, provided that you ignore vacuum energy (VE). Near the singularity, VE does not play a significant role, but in the universe at large, it is apparently the dominant form of energy - and it has a constant energy density, not decreasing with increased volume.

Black holes (BHs) do not quite occupy zero space - it is only the theoretical central singularity that (possibly) 'occupies' zero space. However, we know that all out theories blow up at that point, but something interesting should happen there - we just don't know what.

Your guess of a white hole, spewing out material in some other dimension/universe is as good as any. String theories possibly allow such things (most have six other dimensions to work with), but it is not very conclusive, AFAIK. Whether all the 'rules' of physics would be reversed, I don't know, but I doubt that...

-J

I found this to be 'illuminating' - others may also:

Black Hole in the Milky Way

Cheers!