The Universe is a Hologram

[Brian W (Brian)]

I just figured out it is not possible to find the centre of the universe for lots of reasons not the least of which is that the centre expanded with everything else so in one way we are all in the centre due to expansion and now you all lay this before... this may take a wee bit of thought.
Brian

[CraigS]

G'Day Brian;

I think its all still fairly consistent with our previous discussions (?)
(I hope so, at least) ….

The key here, is to separate the 'Observable Universe' from 'The (total) Universe'. The 'boundary' of the Observable Universe is a 'Cosmic Horizon', (which can be more accurately defined by a Hubble Sphere and a Particle horizon). These are then analogous to a black hole's Event Horizon which is used to predict the behaviour of things furthest away from us (moving at or greater than speed of light).

The hologram bit is where it gets complicated because this shifts into an Information Model paradigm, and it is definitely non-intuitive.

Have fun.

Cheers

[cwjohn (Chris)]

CraigS

Some brief comments.

I have the greatest of admiration for Leonard Susskind, expecially as a gifted writer and lecturer, but clearly he is not afraid to let his imagination run a little wild as Woit and Smolin have pointed out in their respective books. Let us remember that these theories are based on assumption after assumption with no prospect of verifiability and thus by any basic analysis no longer qualify as scientific. This is not to say they are not valuable and thought provoking, and one may, after some considerable contemplation accept them as likely or not, but they need to be put in a separate class to what we would call normal scientific discourse.

I would disagree strongly that the prospects of falsification or confirmation always justify the effort. This argument could be used to justify any research on any matter irrespective of ethics, cost or just plain triviality. There is only a certain amount or resource available and that resource needs to be allocated on merit.

In regard to velocities I think you know well I was not referring to recessional velocity this being a property of the received redshifted photons. It is misleading to say "We see many galaxies moving at, or greater than c as this is a comoving velocity relative to our reference frame. Yes, they are theoretically receding from us at greater than c mainly due to the expansion of space, but the velocity that they are actually moving at would be a matter of some debate depending on your reference frame.

[CraigS]

Chris;
Interesting comments and thank you for them.
A couple of my own follow:

Originally Posted by cwjohn

I have the greatest of admiration for Leonard Susskind, expecially as a gifted writer and lecturer, but clearly he is not afraid to let his imagination run a little wild as Woit and Smolin have pointed out in their respective books.

Susskind was a big party-goer from the seventies, I believe !
The battle between Susskind and Smolin/Woit kind of ended up as a stalement, I think (?).

Originally Posted by cwjohn

Let us remember that these theories are based on assumption after assumption with no prospect of verifiability and thus by any basic analysis no longer qualify as scientific.

I would see this as a bit of an over simplification. Theoretical assumptions (of the type we're discussing usually have a sound basis of foundation).
Whilst String Theory may not be directly verifiable at present, the predicted effects and behaviour of strings may, (or may not), be observed in other, (perhaps), unrelated phenomena. Knocking it all on the head, one way or another would seem to be a good idea, (if it is at all achievable).

Whether these matters are scientific or not, is a philosophical/intellectual debate. No one wins in these.

Originally Posted by cwjohn

This is not to say they are not valuable and thought provoking, and one may, after some considerable contemplation accept them as likely or not, but they need to be put in a separate class to what we would call normal scientific discourse.

Aha .. I agree we need another name for it all !
I would say they have value because they are highly logical and have a very high degree of internal integrity. To me, this demonstrates the quality of what they have to say.

Originally Posted by cwjohn

I would disagree strongly that the prospects of falsification or confirmation always justify the effort. This argument could be used to justify any research on any matter irrespective of ethics, cost or just plain triviality. There is only a certain amount or resource available and that resource needs to be allocated on merit.

That's cool .. I agree that's a complex issue ... I'll leave all that up to governments who make the funding decisions. Looks like Hogan succeeded in convincing someone !

Originally Posted by cwjohn

In regard to velocities I think you know well I was not referring to recessional velocity this being a property of the received redshifted photons. It is misleading to say "We see many galaxies moving at, or greater than c as this is a comoving velocity relative to our reference frame. Yes, they are theoretically receding from us at greater than c mainly due to the expansion of space, but the velocity that they are actually moving at would be a matter of some debate depending on your reference frame.

Actually, no .. I didn't understand where exactly you were coming from. I guessed you were coming from metric expansion of space. I guess if we're dancing around these concepts, we should be clearer about the orientation when we shift from a mainstream, scientific concensus view.

Its all very interesting.
We have many folk who drop in here in the Science Forum and I think I'd have to say, that very few have a common perspectives on all these matters. Some folk completely reject Metric Expansion, some believe gravity is communicated by 'push' particles, some believe plasma is responsible for Pulsars, Quasars, Neutron Stars and that Black Holes have no place in their thoughts. These conversations usually result in frustration due to a break down in logical discussion flows.

The mainstream consensus perspective has a high degree of interconnecting logic, which is why I attempt to steer conversations towards these perspectives, as a common basis from where to go in those conversations.

I agree with what seems to be your stance, (if you'll allow me to paraphrase .. correct me if I'm overstepping the mark here, just trying to get where you're coming from so I don't tread on any (more) toes)…
"Don't believe any of it .. but do attempt to understand it"

(Oh well .. at least that's my view on it all).

Cheers (& thanks for your conversation).

[avandonk]

Can someone explain to me what the term holographic universe means as I think it is another cop out as to our fleeting reality.

So far I have seen pathetic attempts at Plank noise to explain the "WHAT".

It is drivel as then our reality is just moved to a projector!

Bert

[CraigS]

Bert;
My best efforts are on posts #10 and #11.

Seems to me its just a different way to envisage our universe (and thus explain our reality). It seems the term is formally "The Holographic Principle" as distinct from the term you use: 'Holographic Universe' (I'm not sure what this is).

IF we picture the observable universe as information bits on our Hubble or Particle Horizons, then we can explain some observations of the behaviour of Galaxies, matter, etc it/they approach this 'boundary' or 'horizon' (or holographic 'film').
The mathematics of Event Horizons (String Theory) around black holes can be used to describe this.

I'm not at the point of understanding of how it may be used to explain our 'reality'. Maybe that's not what the Holographic Principle is about at all (ie: perhaps the title of this thread is a misconception on my part .. I didn't understand any of it when I started the thread).

Happy to hear from others on this bit.

Cheers
PS: The bits radiate 'inwards' (via the Hawking Radiation descriptions/mechanisms). I think this explains the 'projector' bit (?)

[cwjohn (Chris)]

Originally Posted by CraigS

Chris;
I agree with what seems to be your stance, (if you'll allow me to paraphrase .. correct me if I'm overstepping the mark here, just trying to get where you're coming from so I don't tread on any (more) toes)…
"Don't believe any of it .. but do attempt to understand it"

(Oh well .. at least that's my view on it all).

Cheers (& thanks for your conversation).

Just so - paraphrased perfectly.

As a side issue I see a researcher has just received an ARC grant for $26 million to verify the feelings of those suffering the plague 500 years ago. This amply illustrates my point that falsification and / or verfication is not the only necessary precondition for funding with our hard earned tax dollars.

Cheers

[avandonk]

How many of you have seen a hologram in a real laser laboratory?

Let alone a full colour one.

Thought so.

Bert

[CraigS]

Gee Bert;

I've seen a hologram.

And it looks nothing like our reality.

Does that mean I should trash the whole concept, forget about the whole thing and not bother to try and understand where these guys are coming from?

If I did that, I'd never learn anything !

Cheers

[avandonk]

OK before you postulate reality is a hologram even if it is a three dimensional projection. The projector has no control over the image.

Who is the projector! God?

Some wanker discovers Plank noise and Quantum Mechanics and he has orgasmic prophesies.

The whole trick with reality as I have explained before is that it is totally self referential.

Bert

[CraigS]

Ok .. I'm not sure that these guys are trying to get tied up in an implied relationship between reality and a hologram. (Neither am I).

It seems to be more like a thought experiment .. a model.

They may learn more about QFT and String Theory, by doing the experiment that Hogan's on about.

It looks more like a gravity wave detector to me.


Cheers

[avandonk]

A gravity wave detector needs two arms in the order of a few kilometers long. The whole device would need to be kept at very low constant temperatures.
We are looking for about a differential of a very small part of a nucleus of an atom. A very big ask!
Interferometry is good but not that good yet!

Bert

[CraigS]

Ok .. just re-read the original news articles.
It appears all this started because of an unaccountable noise phenomenon in the GEO600 gravity wave detector in Germany. Enter Hogan …

To Hogan, the jitteriness suggested that the experiment had stumbled upon the lower limit of the spacetime pixels’ resolution.
…
In order to test the theory of holographic noise, the frequency of GEO600´s maximum sensitivity will be shifted towards ever higher frequencies. The frequency of maximum sensitivity is the tone that the detector can hear best. It is normally adjusted to offer the best chance for hearing exploding stars or merging black holes. Even if it turns out that the mysterious noise is the same at high frequencies as at the lower ones, this will not constitute proof for Hogan's hypothesis.
..
Unlike the other large laser interferometers, GEO600 reacts particularly sensitively to lateral movement of the beam splitter because it is constructed using the principle of signal recycling. Normally this is inconvenient, but we need the signal recycling to compensate for the shorter arm lengths compared to other detectors. The holographic noise, however, produces exactly such a lateral signal and so the disadvantage becomes an advantage in this case
...
The smallest possible fraction of distance is called the 'Planck length" by physicists. Its value is 1.6 x 10∧-35 m – this is impossible to measure by itself.
…
Hogan suggests that the mirrors in an interferometer wander relative to one another in very rapid steps of the tiny Planck amount, that accumulate during the time of a measurement into something as large as a gravitational wave would produce.
...
“The shaking of spacetime occurs at a million times per second (1MHz only!), a thousand times what your ear can hear,” said Fermilab experimental physicist Aaron Chou.
...
The whole trick, Chou says, is to prove that the vibrations don’t come from the instrument. Using technology similar to that in noise-cancelling headphones, sensors outside the instrument detect vibrations and shake the mirror at the same frequency to cancel them. Any remaining shakiness at high frequency, the researchers propose, will be evidence of blurriness in spacetime.

Evidence … (?) … maybe … until someone else comes up with a better hypothesis.

This is totally reminiscent of Penzias and Wilson stumbling across the CMBR. I guess we'll see how it all pans out. Should be working sometime next year.

Cheers