# What's the Use of a Susskind Hologram?

(this question may need to go to sandbox for refining)

Leonard Susskind proposed that the surface of a black hole might be kind-of recording device for everything falling into it. Where 3D of space + 1D of time become 4 dimensions of space, practically.

I'm trying to imagine a culture living on or near one of these things. They have some properties:

• They can enter or leave at will (no more effort than taking a flight).
• Modern life would necessarily be digital beings, made of information (unless I'm mistaken).
• Something outside the black hole makes "updates" possible to the information stored in the black hole.
• It may be possible, through some other interference property, to update points in x,y,z,t without changing it.
• A thousand or a few million years of history are available as real estate for living. So you can stack people in both time and space.
• Because x,y,z,t are actually all spacial dimensions, cause & effect is now optional
• You can travel instantly (in relative time) to another x,y,z,t point; although there may be a non-zero absolute cost to moving.
• Probably possible to completely overwrite data in a spot of x,y,z,t to dedicate it to some present-day purpose. But would bemoan the loss of "greenfield" history to paving it over with the present.

What distinguishes a society living in, or in close proximity to, a Susskind hologram (assuming they exist)? Are there any benefits (over digital and physical real-estate) to living in one?

• Methinks one of the factors that you will have to come to grips with is the actual area in our spacetime of the surface. How big are you proposing that this black hole Susskind Hologram is? – Justin Thyme the Second Jun 7 '20 at 13:47
• the author is arguing that information do not simply disappear in the blackhole so he proposed that they are encoded onto the surface of a blackhole instead, I remembered somebody else went even further proposing hologram within a hologram to resolve Hawking's error. – user6760 Jun 7 '20 at 14:16
• "They can enter or leave at will ": no, they cannot. The fundamental idea about black holes is that inside the event horizon the radial direction away from the black hole is time-like: nothing can get out because it would imply time travel. Once something, anything, has crossed the event horizon, the event horizon is in the past and the black hole is in the future. That is to say, if they can go some place and come back, then that place is not inside the event horizon of a black hole. It doesn't matter what technology they have, it doesn't matter how powerful their engines are. – AlexP Jun 7 '20 at 16:59
• The black hole surface is 2-dimentional, not 4-dimensional. – Anixx Jun 7 '20 at 20:01
• If there's no timelike dimension, then there's no causation. If there's no causation, then you have the wormhole aliens from Star Trek DS9. – Kevin Jun 8 '20 at 17:16

Some ideas for consideration:

## Deterministic Social Sciences

A computer simulation is only as good as the model. Models try to fit data. However, the limitations of cost and time limit the resolution and volume of information we collect.

As a result, many fields that are incredible complex -- social science, and medicine as two examples depend on statistical strength to back up hypotheses.

But what if every detail, no matter how mundane, was meticulously recorded by an dispassionate event horizon? Study participants couldn't lie, or misunderstand the instructions. No confounding variables.

Assuming social and medical sciences aren't already "good enough" at this point, inside the hologram would be a great place for researches to try to find deterministic models that precisely explain social behavior.

This might be applicable to medicine as well.

## Deterministic Quantum Mechanics, Pilot Wave Theories

I have a feeling that really understanding these subjects would be a pre-requisite to being able to digitally enter or leave an event horizon. But in case they are not, this would be the perfect high-energy lab to study every event in super-slow-motion, and with as much detail as the event horizon can provide.

## White Holes, Fast Radio Bursts

It may be natural that black holes sometimes emit energy. If this is true, it would probably be an enabling technology to enter and leave the event hologram. It would also be an important field of study, especially since these eruptions reduce the energy of the event horizon, reduce the area by $${\Delta E} \over A$$, and reduce the information inside the hologram.

## Studying the Chemistry of the Singularity

Neutron stars may have cores of quark matter. It's also possible that the periodic table opens up to stable exotic matter past 300 protons, which might be found in some large neutron stars, and possibly around the singularity. It may open up a whole new fields of chemistry, that a simulation could not begin to guess at.

There may be even more exotic things within the black hole itself.

## Studying Unification Theories

You might be able to get a better view of extremely high energies and how forces flow together inside the event horizon. A digital world will only be able to simulate the vantage points you can construct with your imagination.

## Non-Linear Fine Structure Constants

If the fine structure constant does turn out to vary, this is potentially a very good place to study it from. It might be possible to set-up labs with differing fine-structure constants, and study how physical laws change in these regimes. It might open up a new branch of engineering, tinkering with what we currently consider constants to achieve practical effects.

If I understand Susskind's concept correctly, the source of the information recorded on the surface of the event horizon is light from the region surrounding the singularity. If this is the case, perhaps the event horizon would encapsulate a history of the region. Distant objects and phenomena which existed far in the past could potentially be studied at resolutions not possible otherwise. This scenario would fit well with an advanced civilization devoted to archeological pursuit. A society of scholars able to occupy the singularity might decide to establish an Academy there. Perhaps a hyper advanced library similar to Isaac Asimov 's Foundation.