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astromark
2012-Jan-21, 06:35 AM
I see a recent news feed regarding what might be imaged

when you are looking to photograph a Black Hole.

That a group of scientists were looking to photograph a BH.

We are told and except what is alleged to be happening and that such a mass

Holds the photons from reaching us. I have read a slightly different view.

That the presence of such mass in such density begins to distort the space it occupies.

So based on that I would think that as you approach a BH it must look like a star..

Thats what it is.. Even as its interior is being torn asunder the view from outside would be as before..

You see the photosphere of a boiling mass in falling and with massive energy outpouring..

I do not imagine a BH looks black

Not until you have reached a point where you would no longer have any interest in its apperance..

pzkpfw
2012-Jan-21, 07:15 AM
So what exactly is your question?

Hornblower
2012-Jan-21, 05:03 PM
I see a recent news feed regarding what might be imaged

when you are looking to photograph a Black Hole.

That a group of scientists were looking to photograph a BH.

We are told and except what is alleged to be happening and that such a mass

Holds the photons from reaching us. I have read a slightly different view.

That the presence of such mass in such density begins to distort the space it occupies.

So based on that I would think that as you approach a BH it must look like a star..

Thats what it is.. Even as its interior is being torn asunder the view from outside would be as before..

You see the photosphere of a boiling mass in falling and with massive energy outpouring..

I do not imagine a BH looks black

Not until you have reached a point where you would no longer have any interest in its apperance..

If we are close to a black hole that is in front of a bright background, the prevailing theory predicts a circular silhouette surrounded by a distorted view of the background. The predicted diameter of the apparent black disk depends on the mass. If the observed diameter is different from the prediction, that would be evidence that general relativity in its present form is breaking down under such extreme conditions. If such turns out to be the case, it will be back to the theoretical drawing board.

This of course is assuming that the black hole is in a vacuum and is not accreting a lot of stuff. Otherwise there would be luminous material surrounding it and interfering with our view.

astromark
2012-Jan-21, 08:31 PM
So what exactly is your question?

There was to be a question.. but my available free time changed.. I got distracted.. SOoooo...

What do you expect the BH to look like as you approach it ?

Selfsim
2012-Jan-21, 09:03 PM
I see a recent news feed regarding what might be imaged

when you are looking to photograph a Black Hole.

That a group of scientists were looking to photograph a BH.

We are told and except what is alleged to be happening and that such a mass

Holds the photons from reaching us. I have read a slightly different view.

That the presence of such mass in such density begins to distort the space it occupies.

So based on that I would think that as you approach a BH it must look like a star..

Thats what it is.. Even as its interior is being torn asunder the view from outside would be as before..

You see the photosphere of a boiling mass in falling and with massive energy outpouring..

I do not imagine a BH looks black

Not until you have reached a point where you would no longer have any interest in its apperance..
As I understand it, the Holographic Principle caters for the two common descriptions seen from both the infaller's, and the observer's perspectives.

The infaller 'lives' in a normal three dimensional world, and passing through the event horizon experiences nothing particularly special.

The observer, (from a quantum informational two dimensional perspective) however, sees the infaller torn to shreads, and their bits of information dispersed across the event horizon which appears as an extremely hot, dense 'soup'.

Both views are correct.

The observer's view of the event horizon appears hopelessly scrambled, as it represents three dimensional information encoded into Planck-sized pixels, but in only two dimensions. However, the infaller's bits are able to be re-constructed, and thereby serves as a permanent record of everything which has fallen into the black hole.

This reconstructed 'image' is where the term 'Holographic' comes from ... the event horizon would 'appear' as a holographic plate image.

Pretty cool stuff, if you ask me. And it appears that the Holographic Principle seems to be regarded by most scientists, as 'mainstream theoretical science', (even if it is unobservable ...and presently unverifiable ).

Hope this helps.

Regards

astromark
2012-Jan-21, 11:14 PM
I can imagine a black hole., but I can not imagine what it might look like.

I can 'see' the plasma state hot soup as I approach it..

I do not think from any frame of view a black hole will look black..

pzkpfw
2012-Jan-21, 11:19 PM
I do not think from any frame of view a black hole will look black..

For you to see something, photons are getting to your eyes. Where are these photons coming from, when you look at a black hole?

Selfsim
2012-Jan-21, 11:46 PM
The interesting thing about the Holographic Principle perspective, is that it takes us beyond the limitations of our own eyes, (in perceiving only band-limited photons), and allows us to 'envisage' what properties remain of the matter, after it has fallen through the event horizon.

The most basic law of thermodynamics is that information about matter is always preserved .. even after the matter (to which is pertains), has fallen though the event horizon.

The mathematics underpinning the Holographic concept, allows us to extend our 'view', without violating any of the known laws of physics.

When one thinks about it, photons received by the eye are interpreted by our brains. The Holographic Principle allows us to use another part of our brains to perceive what must remain.

It is one of the most unintuitive, but 'conforming', of all concepts in Physics.

Fascinating stuff .. provided one is prepared to accept the mathematics.

Oh .. and it doesn't necessarily have to be 'believed'. :)

Cheers

David Holland
2012-Jan-22, 05:30 AM
The interesting thing about the Holographic Principle perspective, is that it takes us beyond the limitations of our own eyes, (in perceiving only band-limited photons), and allows us to 'envisage' what properties remain of the matter, after it has fallen through the event horizon.

The most basic law of thermodynamics is that information about matter is always preserved .. even after the matter (to which is pertains), has fallen though the event horizon.

The mathematics underpinning the Holographic concept, allows us to extend our 'view', without violating any of the known laws of physics.

When one thinks about it, photons received by the eye are interpreted by our brains. The Holographic Principle allows us to use another part of our brains to perceive what must remain.

It is one of the most unintuitive, but 'conforming', of all concepts in Physics.

Fascinating stuff .. provided one is prepared to accept the mathematics.

Oh .. and it doesn't necessarily have to be 'believed'. :)

Cheers

I'm pretty sure this is not mainstream science. Do you have a cite for: "The Holographic Principle allows us to use another part of our brains to perceive what must remain."?

Selfsim
2012-Jan-22, 07:04 AM
I'm pretty sure this is not mainstream science. Do you have a cite for: "The Holographic Principle allows us to use another part of our brains to perceive what must remain."?
No .. and I think I get your point (?) :) The shallowest views of the principle are barely visible to some of its proponents. The deepest understandings of it however, I think, are beyond most.

In my defence, I did qualify all of the above with:

it doesn't necessarily have to be 'believed'. ...and I don't believe I specified exactly which of 'our' brains. :) .. (certainly not mine !)

As an aside, (and for the record .. if interested), I think the main papers leading to the Holographic Principle were covered in the following papers:

1. L. Susskind, The World as a Hologram, hep-th/9409089 (number of cites > 125 .. I lost track after that);
2. C.R. Stephens, G. ít Hooft and B.F. Whiting, Black Hole Evaporation Without Information Loss, gr-qc/9310006 (number of cites > 125 .. I lost track after that);
3. Edward Witten, Anti De Sitter Space And Holography, hep-th/9802150 (number of cites > 125 .. I lost track after that);
4. L. Susskind and E. Witten, The Holographic Bound in Anti-de Sitter Space, hep- th/9805114 (number of cites > 125 .. I lost track after that);
5. E.Kasner, Am.J.Math 48,217 (1921) 6. A.Chodos and S.Detweiler, Phys.Rev.D21,2167 (1980)
6. W. Fischler, L. Susskind: Holography and Cosmology Jun 1998 http://arxiv.org/pdf/hep-th/9806039v2.pdf

I have seen Susskind stating that he thinks that the Holographic Principle is considered as "consensus science", by most of his theoretical physicist colleagues, and going by the number of cites of the above papers, it would be difficult to disagree.

Regards

astromark
2012-Jan-22, 11:18 AM
...
For you to see something, photons are getting to your eyes.

Where are these photons coming from, when you look at a black hole?

From that which is not yet inside the event horizon... and I find your comments abrupt.
You are asking me things you know.. Why ? Try reading post one again..
Why the adversarial attitudes people.. Talk with me.. not at me. Calm down... It's just a question.

pzkpfw
2012-Jan-22, 08:00 PM
From that which is not yet inside the event horizon...

That's fair enough, but your first post was not at all clear about when you were observing the black hole, or for how long.

Sure, during the formation of the black hole, you'd still be seeing light from star-stuff that hasn't yet gone inside the event horizon of the black hole - but I doubt that stage lasts very long.

Afterwards, in the long years the black hole exists, all you'd see would be light coming from stuff that is "falling into" that black hole. Which might not be much.