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January 28, 2009


Life in the Real World

We noted last week the possibility that our entire universe may just be a low-res 3D rendering of the real 2D universe, which exists out on the boundary of what we normally think of us "the universe." The hologram that we live in is extremely coarse compared to the boundary universe -- our "pixels" are 19 orders of magnitude greater than those used in the real universe.

I'm thinking that the real universe needs higher resolution in order to contain the same structures that our universe does, only in two dimensions rather than three. But surely four or five orders of magnitude would take care of that? That still puts the boundary universe at a resolution 15 orders of magnitude higher than what's possible here.

So the boundary universe is potentially encoded at a level of detail 1,000,000,000,000,000 times greater than our universe. This raises some questions.

-- What is the boundary universe doing with all that information? Is it keeping better track of things than we are in this universe? Is information about the past available in more detailed form there?

-- Are we just a projection of the boundary universe, or are we what's going on in there? I mean -- is what's happening in there just a two-dimensional version of a guy at a keyboard, is there some kind of uberPhil in the boundary universe writing a blog post that is 15 orders of magnitude more sophisticated than this one?

-- If this (highly improbable) picture of the universe were to turn out to be true, should all metaphysical and cosmological speculations (including the ones I'm making right now) be tabled until we understand the boundary universe better?

Anyhow, that's what goes on in my head up here in the big, grainy, blurry holographic construct that we call the universe.

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January 16, 2009


The World May Be a Hologram

Reader Mike D directs us to this very interesting New Scientist article:

Our world may be a giant hologram

The idea that we live in a hologram probably sounds absurd, but it is a natural extension of our best understanding of black holes, and something with a pretty firm theoretical footing. It has also been surprisingly helpful for physicists wrestling with theories of how the universe works at its most fundamental level.

The holograms you find on credit cards and banknotes are etched on two-dimensional plastic films. When light bounces off them, it recreates the appearance of a 3D image. In the 1990s physicists Leonard Susskind and Nobel prizewinner Gerard 't Hooft suggested that the same principle might apply to the universe as a whole. Our everyday experience might itself be a holographic projection of physical processes that take place on a distant, 2D surface.

The research cited in the article, measurements taken as part of the GEO600 experiment outside of Hanover, Germany, fall well short of proving that we live in a hologram. What we have so far is some background noise very similar to the background noise predicted by Craig Hogan, director of the Fermilab Center for Particle Astrophysics, in his description of the ultimate "graininess" of the universe.

So out at the edge of the universe, you will find the "real" universe: a two-dimensional structure with resolution down to the Planck length. Here in the (fake? shadow? projected?) less-real universe, life is a lot blurrier than that, as our "pixels" are much, much bigger -- 19 orders of magnitude bigger, if I'm reading it correctly. So we live in this big, blurry, 3D rendering of the real, much smaller and more fine-grained universe.

I'm not sure how significant this is. It all sounds kind of strange, but then the universe has to work somehow or other, doesn't it?

A topic for discussion: would such a structure of the universe -- if proved -- tend to support the suggestion that we are living in a computer simulation, or would it be of no relevance?

hologramuniverse.jpg

December 13, 2008


Big Bounce

It's a great question, just exactly the kind we like to ask:

Did our cosmos exist before the big bang?

According to the big bounce picture formulated by theoretical physicist Abhay Ashtekar and others, the cosmos grew from the collapse of a pre-existing universe. Will the same fate await us?It depends. We used to think that the universe was dominated by the gravity of its stars and other matter: either the universe is dense enough for gravity to halt the expansion from the big bang and pull everything back, or else it isn't, in which case the expansion would carry on forever. However, observations of distant supernovae in the past 10 years have challenged that view. They show not just that the universe is expanding, but also that the expansion is speeding up due to a mysterious repulsive force that cosmologists call "dark energy". So if the universe fails to contract, has it already bounced its last bounce?Perhaps not. Cosmologists are still very much in the dark about dark energy. Some theoretical models speculate that the nature of dark energy could change over time, switching from a repulsive to an attractive force that behaves much like gravity. If that happens, the universe will stop expanding and the galaxies will begin to rush together. A question mark also hangs over the universe's matter and energy density, which we have not measured with sufficient accuracy to be sure that the universe will not eventually stop expanding. If it turns out to be a smidgen greater than current observations, then it is a recipe for cosmic collapse.According to the big bounce, in both scenarios the universe will eventually collapse until it reaches the highest density allowed by the theory. At this point, the universe will rebound and begin expanding again - the ultimate in cosmic recycling.

It expands, it contracts. The universe is an accordion!

Or maybe accordion is the wrong analogy -- here's a picture of the cosmos in action:

The slinky is our universe. The stairs would then be...the context in which the universe exists. How big is the staircase, I wonder? Infinite?

More thoughts here.

August 20, 2008


Think of it as the Undo Button

Via GeekPress, quantum weirdness just keeps on getting weirder:

In the latest issue of Nature News, Postdoctoral Fellow Nadav Katz explains how his team [took] a "weak" measurement of a quantum particle, which triggered a partial collapse. Katz then "undid the damage we'd done," altering certain properties of the particle and performing the same weak measurement again. The particle was returned to its original quantum state just as if no measurement had ever been taken.

Because theorists had believed since 1926 that a measurement of a quantum particle inevitably forced a collapse, it was said that in a way, measurements created reality as we understand it. Katz, however, says being able to reverse the collapse "tells us that we really can't assume that measurements create reality because it is possible to erase the effects of a measurement and start again."

Because quantum stuff always sounds so goofy anyway, it's hard to get a handle on just how significant this discovery may be. What we think of as "reality" * is the realization of trillions upon trillions of quantum events. Quantum particles exist in this extended, smeared out, many-places-and-states-at-the-same-time wave-form hyper-reality until they get observed or measured and then it turns out that -- Hey! It wasn't really in lots of different states, after all. It was there and it did that. Reality as we know it is the sum of all those there's and that's produced by all those collapsing waveforms.

We don't actually know much about how or why this is the case. The idea that observation or measurement can be interacting with physical reality to produce results is so patently bizarre that there's a tendency either to:

1. Conveniently ignore that that's what's going on

or

2. Turn it into some kind of spooky mystical thing

The first option is the path of cowards. The universe is weird. Let's deal with it. The second option is a dead end. As soon as we declare the strangeness to be magical, we're finished having a rational conversation about it (which we might not have been having anyway, but at least we were trying.)

So here's the thing. Let's analogize what's happening when a particle goes from an uncollapsed state to a collapsed state. Think of your iTunes when you're doing a random shuffle. A song sitting there on the disk is one of the many possible states of the Song I Am Currently Listening To. When a particular song is picked, the waveform of the entire music library gets collapsed down to just that one song. (It's just an analogy, okay? Stick with me.)

So the iPod plays me a Muddy Waters tune and then starts throwing some Blue Man Group my way. The transition is just a little too jarring, so I take the controls, find some Van Morrison, and (for now) put BMG back into the uncollapsed state. Everybody with me so far? Good.

Here's the problem with that analogy. Tunes playing on an iPod lack a characteristic that we normally associate with quantum waves in the process of collapse. Quantum collapse takes place along something we call the arrow of time -- or may in fact the the thing that defines it. Observation or measurement of quantum states helps push time along. Once we seal the deal as to what a particular outcome was, it's finished. Or at least it's supposed to be. But now Katz is showing us something else.

In other words, what Katz has done -- if I grasp the thing correctly, and I'm sure someone will tell me at great length why I don't -- is not to shut down Blue Man Group and play some other song. He is setting things up so that Blue Man Group never played.

It's not exactly time travel, nor is it even precisely time reversal, but those two concepts come as close as anything I can think of to what this experiment implies. This may be more weirdness of the universe that we're just going to have to get used to, or it may have implications about some very powerful technologies that we will someday have access to. It's hard to say right now.

But I'll tell you one thing. If we really are living in a computer simulation, Nadav Katz has stumbled across an intriguing snippet of source code.


* What a concept.

[Bumped on account of the Instalanche.]

April 29, 2008


The Great Filter

AlphaCentauri_468x318.jpg

Via GeekPress, Nick Bostrom has a fascinating essay at Technology Review in which he lays out his case for hoping that we don't find evidence that life ever existed on Mars or that it exists elsewhere in the universe. Why would we not want to find evidence of life?

According to Bostrom, the apparent silence of our galaxy -- the lack of even one civilization which has advanced to the galactic colonization stage, which we ought to know about if it ever happened, because they would be here -- is evidence either that there is no life out there or that life is in some way blocked from developing to that level. He talks in terms of a "great filter" that evolving life must pass through on the way to the galactic colonization stage. If life is evolving out there in the galaxy, and no aliens have ever shown up here, that suggests that no life anywhere has ever successfully made it through the filter. And if nobody else ever makes it through the filter, we have very little reason to hope that we ever will.

The filter could take many forms. It could be some stage in biological evolution that is just plain difficult to get through. For example, if life rarely makes it to the stage of producing multicellular organisms, and that's the reason nobody is out there, then we've already passed through the filter and it would seem that we are in the clear.

Woo hoo! Let's start colonizing the galaxy.

Continue reading "The Great Filter" »

April 10, 2008


Twin Universes

Beyondtheuniverse.jpgYears ago I remember reading a book by Isaac Asimov (one of his many collections of essays) in which -- if I recall correctly -- he provided answers to questions that he had never addressed before, or that wouldn't have been a good fit for any of his other books. One of these questions was, "What lies beyond the universe?"

Asimov's glib initial response was "non-universe." He then spent some time talking about what non-universe might be. Whatever it is, one would think that it would also be the correct answer to the question, "What came before the universe?"

But maybe not:

Before the Big Bang: A Twin Universe?
Until very recently, asking what happened at or before the Big Bang was considered by physicists to be a religious question. General relativity theory just doesn’t go there – at T=0, it spews out zeros, infinities, and errors – and so the question didn’t make sense from a scientific view.

But in the past few years, a new theory called Loop Quantum Gravity (LQG) has emerged. The theory suggests the possibility of a “quantum bounce,” where our universe stems from the collapse of a previous universe. Yet what that previous universe looked like was still beyond answering.

Now, physicists Alejandro Corichi from Universidad Nacional Autónoma de México and Parampreet Singh from the Perimeter Institute for Theoretical Physics in Ontario have developed a simplified LQG model that gives an intriguing answer: a pre-Big Bang universe might have looked a lot like ours. Their study will appear in an upcoming issue of Physical Review Letters.

“The significance of this concept is that it answers what happened to the universe before the Big Bang,” Singh told PhysOrg.com. “It has remained a mystery, for models that could resolve the Big Bang singularity, whether it is a quantum foam or a classical space-time on the other side. For instance, if it were a quantum foam, we could not speak about a space-time, a notion of time, etc. Our study shows that the universe on the other side is very classical as ours.”

So if a pre-Big Bang universe looked a lot like ours, does it follow that our universe looks a lot like a pre-Big Bang universe? Remember the old computer programming joke that goes...

__AM I IN A LOOP?

__AM I IN A LOOP?

__AM I IN A LOOP?

__AM I IN A LOOP?

Neitzche.jpgThe idea that our universe sprang from one much like it puts me in mind of Friedrich Nietzsche's idea of eternal recurrence. Corichi and Singh talk in terms of our universe being a lot like the one that came before it, but nothing I read above rules out the possibility that this universe is a dead ringer for its ancestor. If that were the case, if the current universe were an exact copy of the one that came before, it would only be reasonable to expect that the next one will also be exactly the same. Or as Nietzsche put it:

This life as you now live it and have lived it, you will have to live once more and innumerable times more; and there will be nothing new in it, but every pain and every joy and every thought and sigh and everything immeasurably small or great in your life must return to you-all in the same succession and sequence-even this spider and this moonlight between the trees, and even this moment and I myself. The eternal hourglass of existence is turned over and over, and you with it, a grain of dust.

How many times have you read this blog post? How many times have I typed it? Is it possible we have each done these things a dozen or a hundred or a billion times, and that we will continue doing so for all eternity?

Also -- and this is the part that makes my head twinge just a bit -- if it is exactly the same thing occurring over and over and over and over...exactly the same...does it really make sense to talk in terms of the number of times it happens? Is one instance of the universe somehow different from an infinite repeating series of the same universe? How? And to what observer?

UPDATE: Michael Darling directs us to this talk by Stephen Hawking, in which he asserts that the universe could have spontaneously created itself out of nothing. As far as satisfactory explanations go, this one has to be the bottom of the barrel. Which doesn't mean it's wrong, of course.

February 21, 2008


Identifying the Coders

Now this is just darned interesting:

The secret of the Universe is not 42, according to a new theory, but the unimaginably larger number 10^122. Scott Funkhouser of the Military College of South Carolina (called The Citadel) in Charleston has shown how this number — which is bigger than the number of particles in the Universe — keeps popping up when several of the physical constants and parameters of the Universe are combined1. This ‘coincidence’, he says, is surely significant, hinting at some common principle at work behind the scenes.

10122.JPG

How about this? What we've manged to do is to uncover a little bit of the source code with which the computer program that we call "the universe" was written. We can see patterns in the code -- amazing numeric coincidences! -- but we still don't know its rules, syntax, etc.We're astounded to find these "coincidences" that would immediately stop being astounding if we knew anything about this underlying structure.

But this raises the question -- which I think we've tossed around before -- about whether source code is merely an analogy, or whether things like this numeric coincidence provide us an extremely remote and yet valid view into the minds of someone, or some group of beings, who exist (or existed) entirely outside of this universe and are responsible for its being here.

And even if it is a remote and very faint view that we have, i think we can say one thing for certain about these beings.

They're geeks.

January 03, 2008


Cosmological Good News / Bad News

I know. You're supposed to start these things with the bad news so as to make the good news seem better, but believe me, it's just more fun to approach this one the other way around.

So with that in mind...

The good news: You know that whole mysterious thing about how the most distant parts of the universe are accelerating? Remember how it threw so much scientific thinking into disarray? Remember all the problems and confusion it caused? Well, the good news is that maybe the outer edges of the universe aren't really accelerating at all. Some clever scientists have come up with an alternative explanation.

Which leads us to...

The bad news: So, okay, their alternate explanation is that time itself may be slowing down. At first, time slowing down doesn't seem to be that big a deal. But it's one of those things that sort of catches up with you eventually. Still, it probably isn't something that we need to get all that worked up about:

In some number of billions of years, time would cease to be time altogether - and everything will stop.

"Then everything will be frozen, like a snapshot of one instant, forever," Prof Senovilla tells New Scientist magazine. "Our planet will be long gone by then."

So to recap: the good news is that maybe the universe isn't weird in a way that we thought, and the bad news is that maybe it's weird in a completely different way that will eventually be the end of everything. But the other good news is that this will only be a problem for those of us planning to live many billions of years. And since most of us planning to do that a also plan to end up functioning in a different substrate -- probably silicon, for starters -- we can look forward to much faster mental function, which will give us a bit of a subjective offset where time coming to an end is concerned.

Plus, we can't rule out subjective immortality kicking in there somewhere down the line. Could happen. We just need to get it started at some point before that final tick of the Big Ticking Clock.

Oh, well. Nothing like a deadline to inspire productivity, I suppose.

universetiedup.JPG

August 14, 2007


Option 2

There's some good discussion here on Nick Bostrom's argument concerning whether our universe is or is not a simulation. We discussed that idea here. A quick recap of Bostrom's argument:

Bostrom argues that one of the following three propositions is most likely true:

(1) the human species is very likely to go extinct before reaching a “posthuman” stage;

(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);

(3) we are almost certainly living in a computer simulation.

I'm starting to like Option 2. Advanced civilizations might run partial simulations of universes, but why simulate an entire universe? Assuming the Many Worlds Hypothesis to be true, any simulation you might want to create is already out there. Accessing and observing those other universes would be no easy task, but then neither would running a simulation of an entire universe.

So I think posthuman civilizations don't run universe-level civilizations, for the same reason that nobody is trying to build a fully operational replica of Hawaii out in the Pacific. Why go to the trouble? Hawaii is already there.

July 15, 2007


Why Does Anything Exist?

Awhile back I fumbled around with the ultimate question - why does anything exist? Wouldn't it have been easier for nothing to exist?

No matter how dogmatic some people seem to be on this issue - both those who believe in God and those who don't - the truth is nobody knows. That being the case, I think humility is the proper response.

I found it interesting to read the thoughts of a couple of guys who don't believe in God - Martin Stritz and George Dvorsky.

Martin almost talks himself into believing God - at least in the Einsteinian sense.

July 02, 2007


What Happened: Two Thoughts

Phil Plait at Bad Astronomy gives us the run-down on Martin Bojowald's Big Bounce Theory of how our universe came into being:

What Bojowald’s work does, as I understand it (the paper as I write this is not out yet, so I am going by my limited knowledge of LQG and other theories like it) is simplify the math enough to be able to trace some properties of the Universe backwards, right down to T=0, which he calls the Big Bounce. The previous Universe collapsed down, and "bounced" outward again, forming our Universe. No doubt the physical aspects of this previous Universe were somewhat different; the quantum uncertainties at the moment of bounce would ensure that. It may have been much like ours, or it may have been quite alien. In his equations, it’s the volume of that previous Universe that cannot be determined. How big was it? It may literally be impossible to ever know.

In the traditional model, talking about anything happening "before" the Big Bang is meaningless. Time doesn't really start until the the Bang occurs. Not that that stops people from talking about it anyway. I know that I, for one, tend to assume that if there are multiple universes, there must be some kind of larger time that could be observed in the relationships between them -- if such relationships ever could be observed! The Big Bounce is intriguing, but if not quite weird enough for you, Plait also directs us to some information on Brane Theory:

For an eternity, our universe lay dormant—a frozen, featureless netherworld. Then, about 15 billion years ago, the cosmos got an abrupt wake-up call.

A parallel universe moving along a hidden dimension smacked into ours. The collision heated our universe, creating a sea of quarks, electrons, protons, photons, and other subatomic particles. It also imparted microscopic ripples, like ocean waves crashing on a shore.

These ripples generated tiny fluctuations in temperature and density, the seeds from which all cosmic architecture—from stars to gargantuan clusters of galaxies to galactic super clusters—ultimately arose.

So in this model, if that other universe had never slammed into us, our universe would never have been anything more than a sort of potential universe. Raising the question of how long (in that larger, inter-universal time) did we have to wait before coming into existence?

Just a little something to ponder as you start your week.

February 15, 2007


Shirley MacLaine, Call Your Office

In our recent discussion about whether this universe is a simulation (and what use intelligent beings might make of simulated universes), Stephen wrote the following:

Why not bring the simulated minds into their world at that point? In fact, wouldn't that be an efficient way to keep the exponential progress of a Singularity going? A post-Singularity civilization could literally bring more and more post-Singularity minds into the "real" world via full simulations of other realities up to the point of their Singularity.

Maybe the beings in the lower-level realities do bring the simulated beings into the "real" world once they achieve Singularity status. Moreover, maybe the same identities or personalities keep showing up in different simulations until they're lucky enough to make it to one that's on the brink of Singularity. What if the software program that makes me me has shown up in many thousands (or millions) of simulated universes, but this is the first time I've been around (potentially) for the Big Leap? Once I'm in the real world post-Singularity, perhaps I will have access to all those different versions of myself that have been run in the other simulations.

This could be seen as a slightly askew take on the soul, reincarnation, and Nirvana. Sure, it sounds a little sketchy, but it's got to be at least as likely as, say, quantum immortality. Or, come to think of it, maybe it's a restatement of the same idea.

UPDATE: As I re-read this, it looks like I have substituted a mathematical model of the soul for the traditional, metaphysical model without explaining how such a thing could exist. I mean, it isn't much of a leap to say that Phil Bowermasters who lead pretty much the same life I do -- or some divergent version of the same life -- over in another simulation/parallel universe would be the same guy I am. But could there be other people in other times and places who are the "same" person as I am. That's a tougher nut to crack.

February 07, 2007


Speaking of Cosmology

I wonder what the relationship is between Gardner's Intelligent Universe and Nick Bostrom's Simulation Argument.

A quick recap of the latter: Bostrom argues that one of the following three propositions is most likely true:

(1) the human species is very likely to go extinct before reaching a “posthuman” stage;

(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);

(3) we are almost certainly living in a computer simulation.

The full argument is lots more fun than any abbreviated version could possibly be, so don't cheat yourself. At first blush, it looks to me as though a simulated universe would fit pretty well with Gardner's idea of a carefully designed intelligent universe. If our universe is a simulation, it explains why so much of what we observe appears to be "rigged" in favor of life in general and us in particular.

But then, why were things that way in the original universe, which we're now simulating? Was it a simulation, too? Or maybe things weren't that way at all in our ancestor universe. Maybe this universe is some kind of bizarre jazz riff on the original. In which case, why does it seem so...mundane? You would think that a wholly (or largely) original universe ought to have some magical stuff in it, or else what's the point?

On the other hand, of course it would all seem mundane to us. Maybe light or gravity are wonderfully exotic concepts, notions that would amaze and delight the inhabitants of the original universe. And perhaps their everyday reality would delight and amaze us. We'll probably never know.

But then again...


UPDATE:

I followed my own link to begin re-reading Bostrom's essay when something caught my attention that I had skimmed over before:

Simulating even a single posthuman civilization might be prohibitively expensive. If so, then we should expect our simulation to be terminated when we are about to become posthuman.

Criminy, now there's a thought. Is anybody at the Lifeboat Foundation working on that possibility?


UPDATE FROM STEPHEN:

So, Bostrom would have us choose one of the three...

Well, I definitely don't buy #2. It seems very likely that any post-Singularity civ would run many, many simulations of its past (or even very weird variations on reality). Alternate history is already an important genre of fiction in this reality.

So I guess I'm left on the fence between #1 and #3. I don't really like either - particularly if Bostrum is right about our simulation being terminated at the point of Singularity. It's death by funnel (#1) or reboot (#3). It's the Fermi Paradox meeting The Doomsday Argument in The Matrix.

Anyway, let's throw out #2 because it is implausible and let's discount #1 because...well I'd rather not believe it. Call it hope. So, I'm left with #3 and Bostrom's rather depressing thought that a post-Singularity civilization might terminate our simulation at the moment of Singularity.

But wait. I think Bostrum is thinking pre-Singularity. Why would a post-Singularity civilization that's running a simulation terminate a civilization at the point of Singularity? Lack of computing power? Naahhh.

Why not bring the simulated minds into their world at that point? In fact, wouldn't that be an efficient way to keep the exponential progress of a Singularity going? A post-Singularity civilization could literally bring more and more post-Singularity minds into the "real" world via full simulations of other realities up to the point of their Singularity.

This would answer the Fermi Paradox and The Doomsday Argument and the puzzling Anthropic Principle. Of course this universe was built to favor life. The civilization that's simulating our universe wants more post-Singularity minds.

Why not just make minds in their reality rather than go to all the trouble of simulating a universe? Perhaps because there is some advantage to the diversity of minds that might develop in different realities.

Just a thought.

January 28, 2007


What We Don't Know

Wired has a run-down on some big questions that remain unanswered (or partially answered). My favorites are:

How can observation affect the outcome of an experiment?

Why is fundamental physics so messy?

How does the brain produce consciousness?

Is the universe actually made of information?

That last one is a good question to mull over when you have some time on your hands (say, for example, when flying across the Pacific.) If everything is information, it explains quite a bit. For example, it explains why the universe seems so inordinately fond of the stuff, as demonstrated by billions of years of MEST compression and the Law of Accelerating Returns. An intriguing, related idea -- if it is not, in fact, just a restatement of the same idea -- is articulated by this guy, who suggests, if I understand him correctly, that the universe is made of numbers. But then he also argues that (maybe) the universe contains virtually no information, so perhaps I'm missing something.

The four questions listed above may be more closely connected to each other than we realize. Consciousness would appear to emerge from information acting upon itself. I am of the opinion that intention is one of the key enablers of this interaction. But then again, it could be one of its results. Observation is another key enabler and/or result of this mysterious interaction. Conscious observation plays some role in the resolution of quantum outcomes. Maybe it enables us to slightly tweak or mess with outcomes. Or maybe it's what's driving the whole show.

One problem that the "universe is made of information" formulation does not solve is the ultimate question: why does anything exist at all? We get to keep chewing on that one irrespective of whether information is a cause, or result, of the existence of the universe.

I noticed that several responses to the various questions (not necessarily just the ones I listed above) made reference to the Large Hadron Collider, which is going on-line soon. We're hoping that the LHC is going to answer a lot of questions for us, but why do Iget this sneaking suspicion that it might raise as many questions as it answers?

August 12, 2006


Top Ten

Weirdest cosmology theories. Via GeekPress.

Personally, I think they left off a really good one.

May 17, 2006


Turtles all the Way Up

Because, hey -- we believe in equal time:

Here's how to build a universe. Step one: start at the beginning of time. Step two: apply the laws of physics. Step three: sit back and watch the universe evolve. Step four: cross your fingers and hope that it comes out looking something like the one we live in.

That's the basic prescription for cosmology, the one physicists use to decipher the history of the universe. But according to Stephen Hawking of the University of Cambridge and Thomas Hertog of the European Organization for Nuclear Research (CERN), the steps are all backward. According to these physicists, there is no history of the universe. There is no immutable past, no 13.7 billion years of evolution for cosmologists to retrace. Instead, there are many possible histories, and the universe has lived them all. And if that's not strange enough, you and I get to play a role in determining the universe's history. Like a reverse choose-your-own-adventure story, we, the observers, can choose the past.

Three things I like about this notion of the "flexiverse:"

1. It comes from Stephen Hawking

2. It suggests that time and space may be infinite. This is kind of a leap on my part; I don't see Hawking addressing that issue directly. Of course, even if the flexiverse is infinite the model doesn't necessarily make any provision for accessing space beyond the tiny playground with a diameter of 15-20 billion light years of which you can observe a small portion on any starry evening, nor does it provide any means of accessing time other than our plodding one-day-every-24-hours approach.

3. In this model, we get to be the turtles. High time, says Phil. High flippin' time.

turtle.jpg
Going up?

On the inevitable question of the theological implications, Hawking does his standard coy thing

SUE: To oversimplify your theories hugely, and I hope you'll forgive me for this, Stephen, you once believed, as I understand it, that there was a point of creation, a big bang, but you no longer believe that to be the case. You believe that there was no beginning and there is no end, that the universe is self-contained. Does that mean that there was no act of creation and therefore that there's no place for God?

STEPHEN: Yes, you have oversimplified. I still believe the universe has a beginning in real time, at the big bang. But there's another kind of time, imaginary time, at right angles to real time, in which the universe has no beginning or end. This would mean that the way the universe began would be determined by the laws of physics. One wouldn't have to say that God chose to set the universe going in some arbitrary way that we couldn't understand. It says nothing about whether or not God exists - just that He isn't arbitrary.

With all due respect to "Sue," I think she's asking the wrong question. As Stephen (Gordon) has pointed out more than once, there is no model of the universe that conclusively eliminates the role of the Creator. So asking whether a particular model does that is kind of a waste of time.

It would be better, IMHO, to ask whether there is a suggestion of infinity here, and what a demonstrably infinite (as distinct from "finite and boundless") universe has to say about what is or is not possible. Wouldn't the ontological argument for the existence of God -- especially Goedel's formulation thereof -- get a boost from the assertion that the universe is infinite?

And I'm just asking. One thing the ontological argument and this flexiverse model have in common -- they both give me a headache.

May 16, 2006


Turtles All the Way Down...

...would be an improvement. Left to my own devices, my philosophical speculations tend towards solipsism supported by the odd tautology. Instinctively, I've always sensed that that kind of thinking was wrong.

Here, at last, is a graphical demonstration of what I believe the problem to be.

Bonus: In the process of looking for this animation, I came across this page full of neat stuff. Enjoy.

January 07, 2006


Wouldn't it be Funny...

...if they found something, and it was Morse Code to the effect of "The Lutherans got it right, but only the Missouri Synod Lutherans. Everyone else, thanks for playing."

Carl Sagan had a similar idea in his novel Contact, where the signature was left (I believe) in...

SPOILERS AHEAD

Continue reading "Wouldn't it be Funny..." »

December 22, 2005


Just Checking

Here's some interesting research:

The physical constants of the Universe are thought to have remained unchanged since the Big Bang; many predictions made by cosmologists depend on it. An international team of researchers are using the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to see if things really have gone on unchanged for billions of years. They're looking to measure two universal constants: the ratio of mass between protons and electrons, and something called the fine structure constant.

If those cosntants have nudged even slightly over the eons, the implications are staggering.

Hat-tip: Posthuman Blues.

December 04, 2005


Landscape of Configuration Space?

I think this idea sounds a lot like this one. Here's my favorite part:

String theory, according to Susskind, presents a compelling explanation of why the cosmological constant is so small, without invoking an intelligent designer. The answer lies in what Susskind calls "the Landscape," which is the set of all possible universes that are compatible with string theory. The Landscape can be thought of as having various locations, corresponding to different values of the cosmological constant and other parameters. In Susskind's estimate, the Landscape contains 10500 types of possible universes -- a stupendously large number far bigger than a googol (which is 10100.)

10500 types of universes seems like a good start. But I wonder...how many do we get of each type?



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