CNN doesn't seem so silly now, does it?

January 18, 2009 1:52 AM

The universe may just be a giant (five dimensional) hologram.
posted by Caduceus (77 comments total)

via
posted by Caduceus at 1:56 AM on January 18, 2009

Neat. I really appreciate when the quality of the writing of articles like that make me believe for a minute that I'm starting to understand this stuff - given that that'll never actually be the case.
posted by progosk at 2:26 AM on January 18, 2009

What is the nature of your physical emergency?
posted by cthuljew at 2:33 AM on January 18, 2009 [2 favorites]

"The One remains, the many change and pass;
Heaven's light forever shines, Earth's shadows fly;
Life, like a dome of many-coloured glass,
Stains the white radiance of Eternity,
Until Death tramples it to fragments."

--Shelley, "Adonais"
posted by bardic at 2:35 AM on January 18, 2009 [7 favorites]

As pointed out in the article, a large scale detector like GEO600 is the wrong tool to use in searching for microscopic distortions of space-time. This is because white noise scales like the square root of distance, due to cancellation. (You wouldn't try to detect the brownian motion of molecules by measuring ocean waves.) It will be a lot more interesting once they construct a micro scale detector aimed specifically at this problem.
posted by metaplectic at 2:37 AM on January 18, 2009 [2 favorites]

If the universe was a five-dimensional hologram that would be totally cool! Not like the time me and my friend Jeff were hanging out and partying and he said "Dude, the universe is like one of those black light posters!" And I thought "Dude, you talking 'bout black body radiation?"... so I didn't say anything. But he continued; "Those posters totally glow under black light! They're like, some parts, are like... they shine when they're dark!" And I knew Jeff was serious about his cosmology, so I never spoke about it again.
posted by twoleftfeet at 2:52 AM on January 18, 2009 [6 favorites]

Our whole universe is just a tamper-proof security sticker for something in a larger universe. And so on, ad infinitum.
posted by codswallop at 3:00 AM on January 18, 2009 [2 favorites]

hey! i was just going to post this :P cf. the holographic principle (previously) and information in the holographic universe:

An astonishing theory called the holographic principle holds that the universe is like a hologram: just as a trick of light allows a fully three-dimensional image to be recorded on a flat piece of film, our seemingly three-dimensional universe could be completely equivalent to alternative quantum fields and physical laws "painted" on a distant, vast surface.

The physics of black holes--immensely dense concentrations of mass--provides a hint that the principle might be true. Studies of black holes show that, although it defies common sense, the maximum entropy or information content of any region of space is defined not by its volume but by its surface area.

e.g. imagine if spaceland (or 'the bulk') were isomorphic to flatland...
posted by kliuless at 3:00 AM on January 18, 2009 [4 favorites]

The grains in that hologram are totally fractal, dude.
posted by flabdablet at 3:06 AM on January 18, 2009 [1 favorite]

Given this, do I need to pay of my credit card, or not?
posted by maxwelton at 3:36 AM on January 18, 2009 [1 favorite]

When I was 19 I was totally enraptured by The Holographic Universe. I took it to my Psych 101 class one day and asked for the instructor's opinion.

"Give me a fuckin' break".

But he was an adjunct, so hey, who knows.
posted by Roman Graves at 3:39 AM on January 18, 2009 [1 favorite]

Reportage about science may just be a giant hologram.

At least it's not an inverted pyramid…
posted by blasdelf at 3:42 AM on January 18, 2009

"The universe may just be a giant (five dimensional) hologram." is way catchier than "Scientists discover unexplained background noise in laser detectors".

Which is not to dismiss the potential importance of noise. After all, Arno Penzias and Robert Wilson got a noble prize for essentially discovering noise.
posted by kisch mokusch at 4:08 AM on January 18, 2009

Arno Penzias and Robert Wilson got a noble prize for essentially discovering noise.

Robert Wilson totally figured it out.
posted by twoleftfeet at 4:52 AM on January 18, 2009 [2 favorites]

Well, fucking duh. Anyone who's dropped more than 3-4 hits of acid at once understands this perfectly, without the maths of course.
posted by mrmojoflying at 4:55 AM on January 18, 2009 [10 favorites]

So is this giant 5-dimensional hologram being projected by an even-more-giant 6-dimensional R2D2?
posted by jozxyqk at 5:25 AM on January 18, 2009

I got your Holographic Universe right here (opens iTunes Music Store)
posted by kcds at 5:39 AM on January 18, 2009

Yes! More science to back up my "universe as RPG" theory. And, I decided I no longer want my consciousness rezzed into a time-travelling space robot, but into a time travelling Lunarian with the additional ability to hear what cats are thinking.
posted by Marisa Stole the Precious Thing at 5:58 AM on January 18, 2009 [1 favorite]

a black hole's entropy - which is synonymous with its information content

It is?

Also, if the universe is shaped like a Pringle, how many of them fit in a can?
posted by languagehat at 5:59 AM on January 18, 2009 [1 favorite]

And I want green eyes next time. GameAdmin, if you're reading this thread, please make a note of these requests, thanks.
posted by Marisa Stole the Precious Thing at 6:02 AM on January 18, 2009

Also, if the universe is shaped like a Pringle, how many of them fit in a can?

this is called brane cosmology the pringles are the branes and the can the 'bulk'

also pringle = negative constant curvature space-time...
posted by geos at 6:10 AM on January 18, 2009 [2 favorites]

also pringle = positive constant curvature of belly...
posted by Science! at 6:16 AM on January 18, 2009 [3 favorites]

Loosely speaking, entropy is a measure of how many ways you can arbitrarily re-arrange a system and still have it behave "the same" (actually, it's the logarithm of that, but nevermind). So, if you imagine the gas in a room, if you have a lot of particles, you could move all their positions around, and you wouldn't notice, thus more particles = more entropy. If you increase the temperature in the room, the particles are moving around faster. Now you could swap around their speeds (e.g. steal 1m/s from one particle and dole it out amongst others), and you have more motion to play with, so higher temperature = more entropy.

Now a black hole seems to have only a few properties that you can observe. It has a mass, and spin. That's about it. If you throw tons of stuff into the black hole, it can be arranged any which way. Presumably stuff is going on in there, so it's moving around. The "information" in the black hole is what state it's in, the entropy is the number of allowed states. So that's the connection, you can't really understand one without knowing something about the other. [Perhaps this long rant is for nothing, and you were just arguing with the word "synonymous". Oh well, I like being a gasbag about this stuff.]

The problem is, that quantum mechanics is time-reversible. If you look at any situation, you should be able to measure lots of stuff, and run time backwards to see what the universe was like before. Maybe you can't measure enough, but it's that way in principle. But if a black hole only has mass and spin, where is all the information about the stuff that was thrown in? The holographic idea is: it's hiding on the surface of the event horizion.

Obviously, this is a hypothesis, not even really a theory, although it has a lot going for it. Applying this idea to the whole universe is more idea than hypothesis. It's an interesting idea though.
posted by Humanzee at 6:18 AM on January 18, 2009 [5 favorites]

Holographic turtles, all the way down.
posted by Devils Rancher at 6:21 AM on January 18, 2009 [8 favorites]

This explanation of the Holographic Universe was a bit easier to wrap my mind around.
posted by Brandon Blatcher at 6:27 AM on January 18, 2009 [1 favorite]

So the real universe is a credit card?
posted by swift at 6:29 AM on January 18, 2009 [2 favorites]

The universe is a great fish in the titanic pants of a mighty turtle.
posted by Mister_A at 7:10 AM on January 18, 2009 [1 favorite]

where is all the information about the stuff that was thrown in? The holographic idea is: it's hiding on the surface of the event horizion

Where Does the Entropy Go?

whoville :P

cheers!
posted by kliuless at 7:14 AM on January 18, 2009

...the excess noise, with frequencies of between 300 and 1500 hertz, had been bothering the team for a long time.

That would explain this incessant ringing in my ears.
posted by ZenMasterThis at 7:50 AM on January 18, 2009

Does this mean I have to read The Secret now?
posted by LMGM at 7:59 AM on January 18, 2009 [1 favorite]

Whoville, eh? I've long been of the opinion that the writing in scientific papers sucks, and needs to be spiced up. I usually advocate allowing the words that scientists actually use to describe their work when they're talking to each other. Unexpected noise isn't a "bother", it's FUCKING FRUSTRATING, AND IF IT DOESN'T GO AWAY, SOME MOTHERFUCKER IS GOING TO GET KILLED! If I can't have the f-bomb, I'd at least settle for Whoville.
posted by Humanzee at 8:14 AM on January 18, 2009

Also, if the universe is shaped like a Pringle, how many of them fit in a can?

42.
posted by jimmythefish at 8:36 AM on January 18, 2009 [2 favorites]

I got the feeling reading that article that the whole "universe as hologram" structure was a build-up to the Pringle statement.
posted by Lipstick Thespian at 9:05 AM on January 18, 2009

I'm trying to wrap my head around this concept without getting all ooey-gooey-new-agey-chewey.

I try to keep a mystical frame of mind while not jumping to weird "we are beings of pure light" bullshit.

So, when I heard about this Thursday night, I did some digging. I'm still not quite sure I understand it all.

This is an excellent video (50 mins or so) that summarizes the basic concept of black hole entropy (though it's basically what Humanzee said, only longer, and maybe more details???)

I think Prof. Raphael Bousso in the video is one of the lead proponents of this theory.

I think Michael Talbot's book isn't about this topic, though i could be wrong...

One thing I'm not sure I understand. Are we living in a 4d universe, and the 3d surface/horizon of the universe contains the information regarding our state of being (that is we are "inside" the universe, as we seem to be) -- Or, are we living on a 4d surface of a 5d universe, and there's a higher dimensional projection of ourselves in that universe? And we ourselves are the data living on the surface?

I don't think using the term "holographic" really helps matters, because it gives the new-agers some hokey pokey bullshit to use beyond the meaning given here. Not that it matters, they'll use whatever they can find to spew their nonsense.

Yet, I admit, I am fascinated from a spiritual element of this. Universe as language inscribed upon surface.

Even so, is there any relation to quantum indeterminancy? The claim of the holographic folks are that we can't see any lower than a certain threshold which is actually *higher* than the planck length, due to this distortion, and I'm wondering if at the planck length quantum indeterminancy breaks down and the only reason things are uncertain is because we have no ability to peer that low. What sort of energy is required to view at the planck length resolution?
posted by symbioid at 9:14 AM on January 18, 2009

I got the feeling reading that article that the whole "universe as hologram" structure was a build-up to the Pringle statement.

Mmm. Crunchy.
posted by rokusan at 9:15 AM on January 18, 2009

Our whole universe is just a tamper-proof security sticker for something in a larger universe.

For Microsoft Universe 7^BETA no doubt.
posted by WolfDaddy at 9:16 AM on January 18, 2009

I'm sorry, the hologram analogy doesn't work for me. For one thing, holograms are static, i.e., they don't change over time. For another, the fact that information about a thing can be encoded in fewer dimensions than the thing itself isn't news. Finally, the encoded hologram is useless without some form of energy doing the projections. As far as I can tell, none of these issues are dealt with in the descriptions.

Now it may be that they've come up with a reasonable theory about the universe, but if so, they're stretching the analogy.
posted by CheeseDigestsAll at 9:22 AM on January 18, 2009 [1 favorite]

Yet, I admit, I am fascinated from a spiritual element of this. Universe as language inscribed upon surface.

Whjat I'm worried about is - when writers start writing about their characters discovering writing creating reality it's a sign that they're played out - are we in some kinda awful Stephen King or John Carpenter routine here?

And the bigger question is, can God create a shark so big that He cannot jump it?
posted by fleetmouse at 9:27 AM on January 18, 2009 [2 favorites]

Pink rays from the ancient satellite.

I thought this whole 'universe as a holographic information projection' thing sounded familiar.
posted by FatherDagon at 9:54 AM on January 18, 2009

The hologram analogy is: complete description of an object, using one fewer dimension. With an ordinary hologram, you have a 2-D surface, but it's encoding the image of a 3-D object. Similarly with a black hole, the 2-D surface of the event horizon, encodes all the information about the 3-D volume within (okay, I'm ignoring time here, but you get the idea). I never personally studied this holography idea, but my understanding is that string theorists believe that strings literally get one end stuck on the event horizon, and the other gets pulled in. (I could be totally off base on that one ---another physicist told me this, and I never looked into it), which is what ties them together. Anyway, with any bounded object, there's dynamics on the surface and in the bulk, and they have to match each other (one way or another) for a hologram to work. If they didn't match up perfectly, no hologram! So, there's a different description of physics for the boundary and the bulk, but there has to be a translation between them. Two different descriptions of the same thing happening, only with a different number of dimensions in the descriptions.

The "universe as hologram" is I think the idea that there is this same kind of forced correspondence between the volume of our universe, and what's happening on the very edge of the observable universe. I think that this particular idea probably is one that needs more than just three dimensions of space and one of time, but is probably connected to string theory.

I personally have a hard time swollowing the "universe as a hologram" idea (almost as hard as swollowing the universe), because I don't think that there's any meaningful boundary. I think that what happened is that a bunch of physicists have constructed a maniacally-sensitive instrument, and they're seeing noise that could be from any number of things. Then again, I dissect crabs for a living, so what do I know?

And... while I hate to be a party-pooper, there's really no spiritual element to any of this stuff, except what you yourself bring to the table. Just lots of really crazy geometry.
posted by Humanzee at 9:59 AM on January 18, 2009 [3 favorites]

Too bloody early. I will read this when brain works.
posted by Samizdata at 10:10 AM on January 18, 2009

Humanzee... Yeah I kinda agree on the "no spiritual element", I consider myself an agnostic materialist pantheist. I guess "philosophical" should be a better term. Platonic logos, perhaps.

I think the reason they're discussing this is that the holographic predictions, at least by that one physicist, claim a result similar to what's being seen. He's admitting that it could be due to a number of things, and only time will tell, but their is a correspondence which is interesting.

I guess what bothers me about the hologram descriptor (and why new-agey folks pick up on it) is that "all in one" concept, that any single part contains the whole. And I don't think, in that regards, this "holographic principle" fits, and I wish they'd choose a better name so that doesn't have such an implication.

It does sound like the original proponents of the theories were string theorists, so I know I should look more into string theory as well.
posted by symbioid at 10:21 AM on January 18, 2009

there's really no spiritual element to any of this stuff, except what you yourself bring to the table. Just lots of really crazy geometry

That's what they said when we found R'yleh, too....
posted by AdamCSnider at 10:21 AM on January 18, 2009 [7 favorites]

And all this stuff is substantiated in which verse of the bible?
posted by notreally at 10:35 AM on January 18, 2009

And all this stuff is substantiated in which verse of the bible?

All of them.
posted by Marisa Stole the Precious Thing at 10:42 AM on January 18, 2009 [1 favorite]

Beat me to it, AdamCSnider.

What I like most about science posts in Metafilter is that there's usually someone around who can explain things in terms I understand, which is not always the case for linked articles.
posted by Caduceus at 10:43 AM on January 18, 2009

You mean we're not a marble hanging on a cat's collar?
posted by Xere at 10:46 AM on January 18, 2009

Perhaps this long rant is for nothing, and you were just arguing with the word "synonymous".

I was arguing with the word "synonymous" (I realize entropy and information are related, but I didn't like that way of putting it), but your rant wasn't for nothing; my understanding of all this stuff is pretty rusty, so I enjoy reading various explanations of it. Thanks!
posted by languagehat at 11:43 AM on January 18, 2009

Now a black hole seems to have only a few properties that you can observe. It has a mass, and spin.

Don't forget charge. One way you get a naked singularity is to drop a mess of charge into it. (As a side note, it doesn't take all that much. The repulsion of two point charges a meter apart, each equivalent to a moles of electrons (the electrons from 1 gram of hydrogen) is like eight trillion killograms worth of force. Suddenly ten or more solar masses isn't that damn impressive.)

That being said, what does the theory you were describing say about naked singularities?
posted by Kid Charlemagne at 12:00 PM on January 18, 2009

Humanzee, I appreciate your translation. It makes sense, but I still object to the use of the term hologram.

To me, saying "the universe is a hologram" implies a certain non-reality, when what they're really saying (I think) is that what we observe in some instances is information from more than one dimension superimposed. A statement like that is a) more understandable, and b) consistent with other theories that suggests >4 dimensions.
posted by CheeseDigestsAll at 12:06 PM on January 18, 2009 [2 favorites]

Yeah, i agree with Cheesdigestall, the use of the term hologram implies lot of things to this science layman, which don't turn out to match the theory at all.
posted by Brandon Blatcher at 12:10 PM on January 18, 2009

It's just like when quantum physicists started started using the term "teleportation" to describe copying a quantum state...the name of the author escapes me, but I think he even admitted in the paper that he was mostly just using the term to generate interest. Good work, guy.
posted by voltairemodern at 12:24 PM on January 18, 2009

Universe as language inscribed upon surface.

Some sort of surface... maybe silicon, with some other elements doped in... that allows for dynamic but ordered interplay between parts of the surface...

;)

So, there's a different description of physics for the boundary and the bulk, but there has to be a translation between them. Two different descriptions of the same thing happening, only with a different number of dimensions in the descriptions.

Doesn't this mean there has to be a third physics for the imaging (in the abstract sense) process as well?

are we living on a 4d surface of a 5d universe

What does 4d surface mean? Is a surface just any subspace whose dimension is one less than the dimension of the general space under consideration?
posted by weston at 12:27 PM on January 18, 2009

Stuff like this kinda makes me want to become a religious fundamentalist. I don't get it, and I might feel better about myself if I could just write it off by reading some holy book written specifically to be understood by people like me. I really can't decide if the idea that I'm living in a hologram is easier to accept than the idea that I was made by an all-powerful cosmic being.
posted by PhatLobley at 12:38 PM on January 18, 2009 [1 favorite]

Kid Charlemagne:
Yeah, I thought about charge, but decided to leave it out. It doesn't seem likely that real black holes would have a large net charge, and I didn't want to get into it. The link that kliuless provided Where Does the Entropy Go? talks about entropy and charged black holes. You can't get a naked singularity though. If you try to dump too much charge in, the black hole will just spit it out. An extremal black hole is one which has the maximum charge that a given mass can bear. The article discusses how slowly adding charge to a black hole gives a different geometry than just blinking one into existence like a djini.

The word "hologram":
Part of the problem with pop science, especially in physics, is that it's like a telephone game. First the scientists have a way of talking to each other. Then they have a way of talking to the press. Then the press writes it up. Each level it gets dumbed down. I seriously find Steven Hawking's books almost incomprehensible, even though I already understand the science that he's talking about. I doubt that the scientists themselves would (seriously) say that the universe is a holograph. Probably they were talking about a holographic map, and things got shortened along the way. There is also, sadly two bad pressures on physicists. The first is what symbioid was complaining about: there are lots of crazy people who want to misuse the ideas of physics, so you have to be really careful what you say, or else it comes out like "Magic is REAL!!!" The other is that physics has captured the public imagination as being a field for intellectual He-Men discussing incomprehensible theories. There's a temptation to make glib analogies that exaggerate the mysteriousness of it all, both on the part of scientists and the press. voltairemodern's example is perfect. I personally want to beat the shit out of Hawking every time he uses the term "imaginary time". But oh no, beat up one elderly crippled man and suddenly I'm a villain!

weston:
You're exactly right. "Surface" is probably a bad word. "Boundary" would be better.

PhatLobley:
Perhaps the Correspondence principle will be some comfort to you. If a theory sounds like it's saying the world is fake, or totally different then it seems, then either it's being explained poorly, or the weirdness is being exaggerated out of context.
posted by Humanzee at 12:48 PM on January 18, 2009 [3 favorites]

Yeah, "hologram" is a loaded term here. It's evocative but misleading unless you're careful.

This is suggesting that the maximum possible information density in a given volume goes up by the surface area of, I'll say, a bounding sphere, rather than by volume, like the number of atoms contained, for example. I'm suggesting a bounding sphere because fractal-like surfaces would lead to really strange results.

If anyone else had the brainfart that the volume might be a constant ratio of the surface area, making this a non-story, for a sphere, volume is radius/3 times the surface area.

Speaking of black holes, I thought that the event horizon was (possibly recently) considered a relative not absolute boundary? Per Wikipedia, "all event horizons appear to be some distance away from any observer." I thought time dilation would lead to a looong trip down to the bottom, with only tidal forces from the gravity gradient causing destruction.
posted by Pronoiac at 12:51 PM on January 18, 2009

To get sufficiently woojee for my taste, consciousness would have to be implicated. I do not see that here.

Also, to escape a mechanistic model of the universe and make room for the spiritual, an implication of unboundedness would be helpful. This is a step back from that it seems to me. I am disappointed.
posted by pointilist at 1:20 PM on January 18, 2009

Wait, so where does Jem fit into all this?
posted by blueberry at 2:00 PM on January 18, 2009

Pronoiac, that quote is describing the perspective of a distant observer. If you kicked someone into a black hole, you would never see them cross the event horizon. Instead they would seem to move in slow motion, they would become ever redder and dimmer. However, if you were kicked into a black hole, you would sail right through the event horizon in a finite period of time ---no one can experience their own time as being dilated. It's very challening to think about event horizons, because they're strange, and often explained poorly too.

Here is something that I just found with google, and seems okay. They key to understanding event horizons is understanding light cones. The event horizon is the point where your light cone has tipped over and pointed towards the singularity. Once you've crossed it, you can no more escape from the singularity then you could point a rocket away from the future and fly into the past.
posted by Humanzee at 3:29 PM on January 18, 2009 [2 favorites]

"Science I don't (yet) understand == ur on drugs d00d" jumped the shark at least 10 years ago.
posted by DU at 4:25 PM on January 18, 2009 [1 favorite]

Instead they would seem to move in slow motion, they would become ever redder and dimmer. However, if you were kicked into a black hole, you would sail right through the event horizon in a finite period of time

So, by extension, would the person who's travelling into the black hole then see the entire life of the universe pass in that finite period of time (assuming, of course, that their eyeballs hadn't been very quickly pulled apart)?
posted by kisch mokusch at 4:42 PM on January 18, 2009

I like, totally knew this.
posted by qinn at 5:22 PM on January 18, 2009

kisch mokusch:
That's a really good question. At first, it seems like you should see the whole future of the universe, because your coordinate 't' (what a distant observer would call time) is racing toward infinity as you cross the horizon. But the same thing is happening to all the other stuff that's falling in behind you. And you don't see things that happen now, you see the light that reaches you from the past. For an observer falling through the event horizon, light that's sufficiently far back doesn't have time (from the observer's perspective) to catch up. So the observer sees time outside the hole speed up, but doesn't see the entire life of the universe.
posted by Humanzee at 7:06 PM on January 18, 2009

Okay, that make sense*. So what about what about when the traveller is facing inward? All that light from the previous objects that went into the black hole but never quite escaped. Does the observer catch up on it? And thus (briefly) see everything that went in before? Is that what you mean by seeing the light from the past?

*At least, as far as I'm ever really likely to understand it.

Sorry for the questions, and I don't want to take up much of your time. But you did write that you liked being a gasbag about this stuff, and there's nobody in my world that I can ask these things to
posted by kisch mokusch at 7:47 PM on January 18, 2009

Forget Holograms, what is emitting methane on mars?
posted by UseyurBrain at 8:46 PM on January 18, 2009

light that's sufficiently far back doesn't have time (from the observer's perspective) to catch up

hey greg egan, no less (oh and sean carrol is working on a book about entropy!), sed the same thing :P
posted by kliuless at 9:24 PM on January 18, 2009

So what about what about when the traveller is facing inward? All that light from the previous objects that went into the black hole but never quite escaped.

Not only does it still fail to escape, but because it fell into the hole before the traveller did, the only way it can go is the same way the traveller is going: endlessly inward. More here.
posted by flabdablet at 9:50 PM on January 18, 2009

Forget Holograms, what is emitting methane on mars?

An arsehole in the spacetime continuum.
posted by flabdablet at 9:51 PM on January 18, 2009

"I really can't decide if the idea that I'm living in a hologram is easier to accept than the idea that I was made by an all-powerful cosmic being."

Just ignore the universe. Maybe it will go away.
I mean, except for gravity, the weak and strong nuclear force, and electromagnetism - what has the universe ever done for us? Nothing.
posted by Smedleyman at 12:13 AM on January 19, 2009

I had never heard of those guys before kliuless, but those are pretty good links (although I sort of have a few bones to pick with the thermodynamically-correct Christmas one). Thanks!

One thing that people can't get out of their heads is the idea that a black hole is an object whose gravity is so strong that light can't escape (not their fault, that's what everyone says). No. It's an object that has warped space and time to the point that time itself points towards the black hole. [Drawing pictures makes this much easier to understand, but I'm not going to try it with ascii, and I didn't have much luck searching last night]. Inside the event horizon, the entire event horizon is in the past, and the singularity is in the future. This means that in every direction you look, you're seeing light that's fallen through the event horizon (after you did). And everywhere you go, you're moving towards the singularity. Same goes for light. Everything moves towards the singularity, where it is destroyed. From the perspective of someone inside the black hole, is as though they had entired a new, tiny universe, and the whole thing was collapsing around them, with nowhere safe to go. The singularity is the moment of the "big crunch".

Incidently (and to hopefully sort of save the derail) this is the idea that justifies the holographic universe. One can describe the edge of the visibile universe as an event horizon (albeit one caused by expansion instead of intense gravity). Thus the mathematics describing physics in the visible universe is similar to the mathematics describing physics inside the event horizon of a black hole.
posted by Humanzee at 4:54 AM on January 19, 2009

Is there any decent mathematics that shows that there is some fundamental difference between the inside of an event horizon and where we are right now?

Putting that another way: how does the Schwarzschild radius of a black hole with the mass of the observable universe compare to the observed Hubble radius?
posted by flabdablet at 5:59 AM on January 19, 2009

Ah. Here we go.
posted by flabdablet at 6:03 AM on January 19, 2009

All of which ties in nicely to a crackpot personal worldview I've been chewing on for a while. It's my own little time cube.

It is a matter of observed fact that in general, the further away from us a galaxy is, the more red-shifted will be the radiation reaching us from there. A reasonable conclusion to draw from this is that distant galaxies recede from us faster than nearby ones. The standard interpretation of this is that our universe is expanding.

But it's long seemed to me that an alternative view could probably be made to work equally well, which is that it's not so much that the far stuff is expanding as that the near stuff, and us along with it, is accelerating.

What if we are inside an event horizon, a great big one, falling inexorably inward at an accelerating rate?

• one spacetime direction would be privileged (time would have an inevitably inward-pointing arrow): check.
• information-bearing radiation would only reach us from the past (outward), not from the future (inward): check.
• Things further outward than us would not be falling inward as fast as us, because they haven't been falling for as long as we have, so the further away they were the more they'd be red-shifted: check.

Well OK then mister drug-addled loon, I hear you say: if we're falling into a singularity that's dead ahead of us time-wise, when are you tipping we're going to encounter the serious weirdness inherent in hitting it?

Well, we're not.

For starters, the faster we fall, the more time slows down for us. We have rest mass; given a constant tendency to accelerate, we will approach the speed of light asymptotically. And the closer we approach that speed, the slower time runs for us, and the longer our future looks to us. We can pretty much keep partying on indefinitely.

Which is why the singularity - the point of infinite spacetime curvature - is nothing we need to be concerned about. It's nowhere we can ever go, which is to say: it's not included in reality. Which is a perfectly good reason for it to make no kind of sense.

For seconds, what we're falling into is not a singular singularity. We're in a galaxy, right? And our galaxy has a black hole in the middle, right? So at some point we (as in, the particles that presently constitute us) are pretty much doomed to spiral on in there, yes?

Our local black hole is our local future. Our local time axis warps and twists until it ends up in there.

Same goes for other observers in other galaxies. Everybody's own time axis ends up pointing right on in to their own local galaxy-centred black hole.

Which means that the future - the direction inward from the huge event horizon we're all inside of - is, by observation, branched.

Which means there's no reason to suspect that the future inside one of our local galactic-centre event horizons is any different.

Which means that the whole shebang really is fractal.

Are we passing this pipe left or right?
posted by flabdablet at 7:12 AM on January 19, 2009

Erf. You've got some plus/minus signs off there. Inside a Schwarzchild event horizon, space is contracting. That means that light that reaches you will be blue-shifted, not red-shifted. The further away the object appears to be, the more it will be blue-shifted, since the light has traveled farther/longer through contracting space.

Also, one never experiences time-dilation in one's own reference frame, the rest of the universe may seem to be sped up or slowed down, but your own clock is always ticking steadily along. When you accelerate, a non-accelerating observer will say that your clock is ticking slower. That means that you are effectively traveling more quickly into the future (you experience less elapsed time than others). So if you want to dodge the future, moving quickly is the last thing you want to do. Furthermore, notice how I described the situation. I needed a mover and an observer. Statements like "we're going nearly the speed of light" have no meaning by themselves.
posted by Humanzee at 7:58 AM on January 19, 2009

Surely you can't really be saying that my crackpot worldview is wrong.

No pipe for you.
posted by flabdablet at 2:15 PM on January 19, 2009

I remember the first time I found myself in a five dimensional hologrammatic universe. It was right around then that I decided that maybe one hundred and fifty eight hours without sleep might actually be harmful to the human body.

Fortunately, I was too high on catnip and paint thinner at the time to take that revelation much to heart.
posted by quin at 3:29 PM on January 19, 2009

pfft...nah.
posted by es_de_bah at 6:29 PM on January 19, 2009