Black Holes!!!!!!

[baztheman]

Ok so they say that they appear after a star dies and goes supernova.
creating a void which we call a black hole but all things being equal they must have a beginning and a end like a road or time its self..... so here it is folks could this be the doorway to time travel or is the only black holes the ones in my socks ?

[Channel Hopper]

If the picture is you then you must have dirty feet

A (standard) black hole is a phenomenom that has the ability to work outside the normal passage of time, and so its something that the average human will not be able to comprehend.

If you look at it as a piece of space that has everything thats opposite to your usual environment, so it will include

complete and total brilliance (light cannot escape so everything sucked in is still there)
antimatter (the Enterprise drive everyone is looking for )
and time stagnation

so the black hole and whats inside it is actually moving backward in time relative to us. What is happening at present is actually a result of whats about to happen. The black hole is not actually sucking everything in (its only in our timeframe).

What these things are giving out (in its timeframe) are the elements of our bit of the universe which are used and are seen to be sucked back in

Elementary really

[Channel Hopper]

Hmm - Five gold stars - am I eligible to talk to the customers now when they ask for fries or should I stay behind the burger dipenser and mumble ?

[baztheman]

hi hopper its dirty feet here (yep the pic is of me in ibiza)lookin a bit worried when the wife used my camera LOL
nice one with the black holes m8 (i just wondered if black holes were similar to the vortex in a tornado...ie everything sucked in has to go somewhere!!! (kitchen bin theory...my bit just keeps filling!!!!)
maybe its a hole to another universe????? that will make ya think m8...see ya soon...baz

[wolsty]

Most astronomers and theoretical physicists believe that there's a black hole at the centre of our galaxy. There seem to be plenty more scattered around the observable universe. Although no-one's ever seen one directly, they can be inferred from the way they bend light, a process called gravitational lensing.

And they're not voids. Far from it. They are incredibly dense accumulations of matter formed when stars larger than a certain mass run out of the fuel (fusionof hydrogen to helium) which counteracts the force of gravity. When the convection currents stop, gravity pulls the star in on itself and it becomes ever more dense. Everything that's sucked in stays there. Eventually the gravity at the surface is so strong, that nothing, not even light, can escape, because the escape velocity is greater than the speed of light. So the black hole appears black.

They do, however, emit radiation - a product of the energy released as matter is destroyed (ie converted to energy) as it falls in.

If you were near a black hole, you'd eventually be sucked in, but the gravity gradient is so steep that your feet would be shredded before your head: 'spaghettified', as Stephen Hawking put it.

Whether they would permit time travel or whether they are gateways to other universes has not been demonstrated, but Einstein's equations show that, on the edge of a black hole, time stands still (General Theory of Relativity).

The holes in your socks could qualify if they're heavy enough, but they'd just be mini black holes with a mass equivalent to that of Mt Everest.

[baztheman]

Nice one wolsty


some good reading there m8....cheers ,....baz

[Channel Hopper]

Id like a kitchen bin if does what you say

Anyone seen The Arrival with Charlie Sheen, great house clearance tool.

[wolsty]

@ Channel Hopper. Never even heard of 'The Arrival' with Charlie Sheen. I gather from your comments that it's eminently missable.

The kitchen bin is an interesting example of a feature which never quite attains the mass necessary for black hole formation, no matter how much is put into it. I know from bitter experience, because my kids have tried very hard. Rather than take the bulging bin liner to the dustbin, they kept on cramming in more waste but never quite achieved their ambition of making it all disappear - unless my eventually having to take a bag, split at the seams and exuding all kinds of nameless, stinking, nauseating crud counts as disappearing.

LOL

[Channel Hopper]

You need to get a composter from your local council. Eats all manner of kitchen waste and turns it into useful mulch

The Arrival is actually one of the better 'aliens try to take over the Earth' films, but since it arived the same season as Independence Day, it took a back seat in the ratings.

Not bad at all if you like large satellite dishes, a decent plot (Independence Day NOT), and some good special effects without being too blockbuster.

The house cleaning tool will make sense if you watch the film

[Burnt Chips]

Black-Holes (doorway for time travel boll*x) Gateway to another Universe (the dreamers theory) I was reading not long ago that the Black-Hole at the center of the milky-way, was about the size of a football, (like to know who got up there with a football) and that a B-H just sits there waiting for any object to pass too near which is the trapped into gravitational pull (and mulched as C-H so nicely put). My own theory is a bit radical, All galaxys have B-Hs at there centers and the gravitational pull from these holds the galaxys together, The bigger the galaxy the bigger the gravitational force needed to hold together, hence the bigger the B-H. WHAT DO THEY DO ? besides gravity? I think they create matter into Dark matter (we cannot detect it but know about 70% of the universe is made of it) and Dark matter in some form creates matter, so its like a self perpetuating cycle, New for old,
Most of the universe was formed with some violent destruction and Humans being as thet are, always like the more Far fetched theorys as not to show there own vulnerableitys,

[jimbo]

Do any look like this??

[wolsty]

There's little doubt that black holes play a crucial role in holding galaxies together. As to the size of the one at the centre of ours, I'd be surprised if it's as small as a football, although the compression of matter in black holes is very intense. So intense, that 'normal' laws of physics break down.

It's possible to work out the mass and dimension if you have good enough Maths. I'm not proficient at hard sums, so I leave it to the boffins and just read the popular science.

Dark matter accounts for about 90% of the matter in the universe - at least if current theories about expansion/contraction/big bang/big crunch are valid. But what it's composed of is still open to considerable debate.

I've seen it suggested that black holes can 'end' in one of two ways: by 'explosion' when they reach a 'critical mass' - scattering matter of all descriptions across the universe, or by 'evaporation' ie the gradual loss of matter through quantum processes.

The 'explosion' hypothesis seems to have a strong similarity to the Big Bang, in that some authorities suspect that the centre of a black hole is a singularity and the BB is supposed to have begun with the 'explosion' of a singularity.

I'm with you, BC; my money's on a cycle of events being the explanation.

Some difficult ideas here. But it's as good a way of straining your brain as any I know of.

[Channel Hopper]

You could do a lot worse than read through the Nasa archives on these things

http://archive.ncsa.uiuc.edu/Cyberia...lackHoles.html

Maybe better to rename the forum though, Einstein positively denied the existence of the holes, as they fell outside the results of the relativity work .

I remember the size 118 miles from somewhere as the minimum size of a black hole (or at least the event horizon formed by one),

[wolsty]

What particularly upset Albert was Quantum Mechanics. He couldn't (wouldn't?) accept the concept of probability in what he considered to be an 'exact' science. Black holes, though, can be predicted form Einstein's equations.

There's lots of good popular science books which deal with the subject. All available at the local library or bookstore.

[Old Satellite]

What particularly upset Albert was Quantum Mechanics. He couldn't (wouldn't?) accept the concept of probability in what he considered to be an 'exact' science. Black holes, though, can be predicted form Einstein's equations.


Interesting subjects here - i seem to have missed this whoops!!


It is almost like being back at university !!

Any way who is now ready for the discussion of the uncertainty principles? Lets not tell good old Albert though!

regards to all

Old Satellite

[wolsty]

Esoteric graffito:

Heisenberg was probably right.

[wolsty]

Quantum Mechanics? Count me in.

[Channel Hopper]

No strings attached I hope

[wolsty]

Ohhhhhhhhhhhhhhhhhhhhhhhh!

[2old4this]

Here's a few comments on some of the issues discussed in the thread. All of this is theoretical.

Roy Kerr fiorst theorised that spinning black holes may well offer a way to travel back in time. In fact, it's now thought that all black holes spin - so all could be time-machines.

Black holes can exist (theoretically) with quantum-scale radii. In fact it is believed that the universe is peppered with microscopic black holes created in the instant of the big-bang.

The gravity gradient depends on the mass of the black hole. A very large mass black hole will have a large radius (the radius of its event horizon) and will have a relatively shallow gradient. If the black hole were big enough, its gradient would be so shallow as to be not only survivable but almost undetectable at the moment the observer crossed the event horizon. In fact, in some ways our entire universe acts like a gigantic black hole, with everthing trapped inside its event horizon.

I've not come across any recognised scientific theory that dark matter can be converted to ordinary (baryonic) matter (or vice versa). However, it is possible that dark matter is simply baryonic matter - that just happens to be non-radiating (such as dead stars, or extra-solar planets, rocks, dust, etc.).

The radiation (Hawking radiation) emitted by a black hole is not actually derived from the matter falling into it. That matter only imparts momentum to the black hole, but otherwise all "informational" content of it is utterly annihilated or lost (what happens to this "information" is one of the abiding mysteries of black holes).
Hawking radiation has a slightly more exotic origin. It derives from the "virtual particles" that are constantly popping into and out of existence in the vacuum of space (giving rise to the so-called zero-point energy of a vacuum). These particles are "allowed" into existance owing to the uncertainty principle of quantum mechanics. So long as their existance is brief enough, they do not violate any laws. Their energy is allowed to be conjured out of nothing because of its inherent uncertainty in accordance with the Heisenberg principle of quantum mechanics. And their charge and mass is zero since they are always produced in pairs (a particle and an anti-particle).
The vacuum is thought to be a seething mass of such virtual particles constantly popping into and out of existance. In fact, the Casimir effect seems to prove the reality of such particles (but that's another story).

Anyhooooo... since these virtual pairs are appearing constantly everywhere, they are also appearing in the region of a black holes. Imagine such a pair appearing at the event horizon. Whereas they would normally exist for a tiny fraction of a second before recombining and popping back out of existance, what now happens is that one of the pair can become trapped within the event horizon, the other remaining outside. The one that remains outside is a particle of Hawking radiation. It is this which is detected as an 'evaporation' of the black hole.

Interestingly, the rate of 'emission' increases over time. This leads to a runaway effect that in the final moments manifests as an apparent "explosion" of the black hole. I am not aware of any other theories of explosion.

On the Einstein thing - black-holes (i.e. the concept that something may so warp space/time that nothing - not even light - could escape) are predicted by his own theory of general relativity. I expect that what worried him most was the singularity issue - that something in the physical universe could have infinite density.
Personally I believe that this is indeed impossible, and the resolution to the issue lies in the fact that the black hole does not exist in our normal universe. It exists in a shrinking bubble of space/time. From that bubble's frame of reference, time is passing normally, with matter shrinking steadily and achieving steadily higher densities. This persists for ever. In that frame of reference, infinite density would only be achieved after an infinite amount of time.
But from our frame of reference outside the event-horizon, all of this - this eternity of shrinking - seems to take place in a finite space of time. So we appear to have the paradoxical situation of an infinitely dense body existing.

2old

[wolsty]

One suggestion I've seen (and I wish I could remember where) is that the big bang which was the beginning of 'our' universe was the 'explosion' of a black hole which formed in another universe. There seems to be a fair amount of support for the hypothesis that the known universe began with a singularity (no matter how improbable a body of infinite density might seem). If that's the case, there's no problem with the concept of a singularity at the centre of a black hole.

What I have difficulty with is the concept of what the big bang expanded into. Assuming that the universe, whatever its shape, is, by definition, 'everything there is', then there can have been no outside, ie no space into which it could expand. Perhaps there is a mathematical explanation involving highrer dimensions, but I don't have the maths to do those sums.

I agree that Hawking Radiation is one source of the radiation detected from black holes. But it's also been proposed that matter approaching the event horizon emits radiation as it is compressed. It's this radiation which is detected - strictly speaking, of course, it's not the black hole which is radiating, but the matter outside the event horizon.

Einstein seems to have been troubled by two things in his later life. The first was that he couldn't accept the uncertainty aspect of Quantum Mechanics. He was sufficiently well grounded in classical physics to believe that its laws are absolute and admit of no element of probability. The other was that he couldn't devise a Grand Universal Theory which would unite the four basic forces. There's little doubt that his refusal to embrace the implications of Quantum Mechanics seriously hampered his search for the GUT.

[Burnt Chips]

He also believed the speed of light is constant (an assumption i doubt)
as for the singularity theory (black holes would have too get bigger to encompass this theory)
as for radiation emissions around event horizon (who knows)
as i understand my phsyics around the event horizon are dence compact stars, These alone giving off tremendous gravitational forces of there own and then theres the planets we cant see (yet)
so all this chaos and destruction / matter compression/ convertion its no wonder some radiation is escapeing/ the gravity of the B-Hole, If you take IO jupiters moon and europa, as jupiters grav pull is emense compared to europa, which intern is then massive compared to IO, NOW THE BIG 2 RIP IO to pieces, but bits of IO have been found on the moon, the pull of jupiter should have collected this but the slingshot effect comes into play.
Its great what a bottle of BUD can do fer yer.