Black holes

black holes
Now that you've all answered my original question so eloquently, I think this discussion should be published as "Black Holes - the Pachyderm Model." It would win the approval of the scientific community for originality if nothing else. And it would make a perfect Xmas gift for circus-loving black hole aficionados.

Which most of us have been at one time or another. I certainly have although as I matured I did find black holes coming more to the front on my rounds and circuses fading somewhat into the background.

So there is probably a large untapped market out there. I'll ask around in the pub to see what the boys think. I'll not ask any ladies of course because I might get some black looks.

Brilliant !

I went to the circus once.
I found it strangely incomprehensible.

Black holes are much, much easier.

I don't like black holes. They are selfish. They want to suck everything in and grind it up in an irresistable gravitational vortex and then they don't know what to do with it. So they sulk. In the dark.

They are at the opposite end of the journey outwards to meet the stars on which our outgoing, thrusting Faustian mindset is based.

We could loosen them up a bit if we could reach them.

Reach them ?
There's a sizable body of evidence suggesting that we're actually inside one !
No wonder humans are so twisted !
It's like being inside a Dyson vacuuum cleaner.

They're not so bad Helio.

You just have to learn how to sort them out ruthlessly.

My science fiction button is pushed less by the idea of the Black Hole (extreme compression) than by the idea of the Worm Hole (cosmic passage ways).

I forget now which sf writer it was who made the great and perceptive comment that inside a black hole one would measure distance with a stop-watch and time with a ruler.

Interchangeability of time and space?

Not exactly interchangeability. More like role reversal.

Mechanically speaking a "Black Hole" is merely a location in space-time where the accelerations due to gravity exceed the speed of light to an observer. The "pea" analogy won't quite work as we have thought of no way to pack an Earth weight mass into a pea size. The mass must be a good bit larger (heavier) than Earth as the only way we know to compress it is by using gravity. The only way that we are aware of to make gravity is to use mass. Since Earths gravitational acceleration is only about 9.8 meters per second we have a way to go.

If you really feel like figuring it out then find out what mass is required to bring the acelerations of gravity up to 300,000,000 meters per second at whatever distance you can make work. (A hint, this will change with the densities of your masses, whatever you're using).

Or you could look it up, but like most other things, I'd rather do it than read about it. But it will take a bit of reading (foreplay with Chakrasandar and Swartzchild to get the job done. Spelling of names may be a bit off. My apologies to them both

Is that the actual size for that mass, or just the maximum size?
Why doesn't the cherry pip collapse any further than that?

anybody.....?

While essentially a theoretical construct, the Schwarzchild Radius formula has only one variable (assuming c and G to be constants), that being mass. The formula calculates the Schwarzchild Radius (rS) for a given mass, right? You do the math - more mass=greater rS, less mass=lesser rS. If the mass is held constant, as the other factors, c and G, are constants, you have a constant size determined by the mass available. A given mass will yield one specific rS.

Now, I do see one minor thing there - the assumption of sphericity. While I'm neither a cosmologist nor a theoretical physicist, and I didn't stay at a Holiday Inn last night, it is my understanding that due to rotation, a black hole's event horizon is sorta donut-like, more toroidal than spherical; therefore the equatorial radius would be greater then would be the polar radius, but again, that's minor.

However, as mentioned before, the concept of "size" is meaningless applied to the singularity itself, the "heart" of the SR, the "Black Hole" itself, as by defintion that is a dimensionless point, existing precisely and only because the mass density is such that due to gravitometric accelleration, the concept of spacetime ceases to apply, and we enter the realm of quantum theory; a singularity has neither a "where" nor a "when" ... just a "how".


Simple, huh? :wink:

ah I see what I was doing wrong. This calculates the radius of the event horizon, not the radius of the mass at the centre (which I always assumed was zero, or at least not a measurable 3 dimensional thing - thus "singularity").

Note to self: learn to read.

Thanks Timber, appreciate it.

Timberlandko,

I agree that we are currently unable to get any meaningful dimensions for the size of the "cherry pit".

But I have a little further problem that I have mused about often when work becomes boring

Since aparently at some point the mass of a black hole becomes sufficient to bring it into the realm of quantum mechanics, as differentiated from classical physics---- I wonder if the mass and energies of baryonic matter (our stuff) still causes gravity

Why I wonder is because if the "force" of gravity is cancelled in quantum physics it would very comfortably explain the astronomical objects called "quasars".

For instance IF the mass of a growing "black hole" becomes "quantisized" ( like that ) and this negates the force of gravity it may well explain why quasars, and perhaps non rotating pulsars (if there is such a thing) act like they do.

If you have read anything along those lines please mention it. I will be glad to explain further ramifications if you are interested.

One ramification is that our portion of Our Universe merely "changes state" from time to time rather than starting (beginning, banging, created, etc.) Happy thoughts, M.

I've come across what I think is the concept you're driving at akaM - can't really say I'm conversant with it to any extent though. Not at all sure I understand this fully myself, but it seems to me gravity isn't "negated", nor is mass - they just behave differently. In conventional physics, 4 distinct "Fundamental Forces" - Gravity, the Electromagnetic Force, the Strong Force, and The Weak Force - are responsible for the behavior - the "nature" - of all that we observe, all the way down to the sub-atomic level. However, at energy and density levels far greater than the universe's current ambient, Electromagnetic Force and The Weak Force essentially unify into The Electroweak Force, having properties other than either force alone, producing at the sub-atomic level effects we observe only through use of technology such as particle accellerators and mass colliders. Without getting way deep (or, more honestly, deeper than I can go ) into it, we're kinda-sorta beginning to get into the mechanics of nuclear fission here. Anyhow, at a particular energy/density level, there ar 3 fundamental forces, not 4. Increase the energy/density level more, further compacting matter, consequently increasing energy (think temperature - actually much more complex than just heat, but that'll do for this discussion - I think :wink: ), and another sorta "phase transition" (for lack of a better term) takes place, wherein the the Electroweak Force and the Strong Force become essentially indistinguishable from one another, with yet different properties, different effects on matter AND energy than has either distinct force (and here, we've gotten way deeper into nuclear fusion, and much closer to quantum physics, than I can go with any clarity - or surety, for that matter ). All the while, as energy/density have increased, the 4th force, Gravity, has been more less just chugging along unaffected, distinct unto itself and affecting in its customary way the other forces, even as their properties have changed and their distictions have merged. Kick up the energy/density level some more (for instance, as we get closer and closer to the singularity) and what once was 4, then 3, then 2 forces, become a single force, a "Grand Unified Force" (not the same as "Grand Unified Theory - but in a way sorta close to it - kinda on the same order, anyhow), or what is termed "Quantum Gravity" - and now we're officially into Quantum Physics; my already-stretched guide skills ain't gonna help us much from this point on. I'm reminded of an old cartoon; 2 outdoors types, surrounded by the splendor and majesty of untracked wilderness, a dazzling sunset silhouetting distant peaks in the background, are huddled over a map. One of them is saying "I AM the best damned guide in Montana - but, as near as I can figure out, we've been in Canada since sometime early this morning"

I dunno if this image will help you see what I was getting at, but its worth a try. Its a theoretic graphical representation of the evolution of the 4 Fundamental Forces from The Big Bang to the present, but if you look at it from the bottom up, you can sorta get an idea of what happens as we get nearer and nearer to a singularity. Whether or not it is an accurate representation of what happens, it does pretty well illustrate how the math works ... and if the math works, which it does ...



Now, the "Changing State" universe theory does appeal to me (not at all the same as a cyclical universe of expansion, collapse, and re-expansion) for a variety of reasons, and would be at least fundamentally not inconsistent with what I've just tried to describe; if there was a singularity, and if something was at some point and/or time "on the other side" of that singularity, an alltogether "different state" would fill the bill.

I'd better quit now - I think we just crossed into Siberia

What a fascinating discussion my original question has evolved into! I'm way out of my depth, but am enjoying reading your answers and speculating on the breathtaking possibilities.

NWIslander,

You never know what might be hidden in a "black hole" . That may have something to do with why they're named that way


Timberlandko,

I did see what you were getting at. I've run across the same chart. BUT I am kind of wondering if the gravity bar (on the chart) doesn't actually combine with the other forces somewhere around the time shown as "the inflationary epoch"

If gravity disappeared somewhere around those temperatures and pressures we could make a much more elegant Universe. Thats why I asked if you had bumped into any indications that that may happen.

I hope we brought lunch because we are deeeeeep in the woods now

If gravity disappears at times then quasars work much better some singularities disappear also. It also answers the problems with the similar sizes of galaxies.

The "inflationary phase" of the standard "big bang" model wouldn't be required.
(frankly I never liked it very much as the inflationary phase brings in a lot of strange bedfellows that would be as well off stirring cauldrons in the woods; IMO natch )



And IF gravity is actually caused by the relative motions and forces between atomic or sub-atomic particles then when the motions, waves or particles are restrained then gravity itself would disappear. It shouldn't be too much of a trick to collapse a galaxy or a Universe into a black hole sufficiently dense to immobilize the wave forms, particles or electron orbits or what have you.

Too bad it won't work Perhaps I should have packed a month of lunches Best, M