July 22, 2004

Black Holes Suck

(Sorry, I couldn't resist.)

It seems that one of our most cherished beliefs about black holes has been disproved. Stephen Hawking himself delivers the bad news:

"I'm sorry to disappoint science fiction fans, but if information is preserved there is no possibility of using black holes to travel to other universes," he said. "If you jump into a black hole, your mass energy will be returned to our universe, but in a mangled form, which contains the information about what you were like, but in an unrecognizable state."

Another consequence of his new calculations, Dr. Hawking said, is that there is no baby universe branching off from our own inside the black hole, as some theorists, including himself, have speculated.

Well, this doesn't completely disprove the selfish biocosm hypothesis, as expounded by James N. Gardner in his book, Biocosm. But it looks as though intelligence-friendly universes are going to have to find a different way to reproduce. Black holes won't cut it.

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March 09, 2004

Hubble to Rubble?

Is the telescope that just gave us this picture really going to be allowed to die? This huge image may take some time to load, but it's worth it.
Galaxies, galaxies everywhere - as far as NASA's Hubble Space Telescope can see. This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. Called the Hubble Ultra Deep Field, this galaxy-studded view represents a "deep" core sample of the universe, cutting across billions of light-years.
Hubble Ultra Deep Field release text.

UPDATE: More at NPR.

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February 10, 2004

Meanwhile, Here in the Matrix...

Work with me on this:

Ironically, the most significant consequence of the view that the natural world is computational may be the death of the notion that technology is applied science. If both the physical universe and the biological world are best understood in terms of information and computation - concepts that arise from the artificial world of technology - it no longer makes sense to think that technology results from an application of science. Indeed, if computation is the basis of all nature, then science is just applied technology.

If that's the case, then science becomes less purely contemplative and more purposeful, and as fraught with social and political goals as technology is. Scientific theories are more properly viewed not as discoveries but as human constructions. It's already happening in physics: Philosopher of science Andrew Pickering suggests that the quark, which in its unbound state has not - and some say cannot - be observed, should be regarded as a scientific invention rather than an actual particle. In the future, we may come to see the second law of thermodynamics (entropy) as a consequence of information theory and not the other way around.

I know from my discussion with John Smart (check it out; this is an expanded version of the interview, which I have yet to update on this site) that virtually all physical systems that follow an evolutionary/developmental path can be described as computational systems which encode increasing complexity. So, for example, the universe produces stars, which collapse and produce second generation stars, which produce planets rich in organic-friendly elements, which produce life, which produces human beings, who create computers, etc.

But...I strain my brain as I try to formulate the question...where does the encoding take place? A good portion of my personal complexity is encoded in my DNA, so I can see that. And the complexity of the universe that creates stars and then more stars and then Earth is encoded in the laws of physics (I think) so I guess I can see that, too. So the second law is a consequence of Information Theory. I don't have a problem with that.

I guess my question isn't really where does the encoding take place, but rather, who is doing it? If Quarks should be viewed as an invention rather than a discovery, who the heck invented them? Or by an "invention," do we simply mean the product of an advanced information-encoding/information-processing system?

If that's the case, then I think it makes just as much sense to say that quarks were discovered as to say they were invented. Is somebody running the Matrix? Or is it just running itself?


via KurzweilAI

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January 05, 2004

Old Galaxies, Too

Following close on the heels of this morning's entry about how there are many sun-like stars in our galaxy, most of them quite a bit older than our own sun, here's a report about some very old galaxies that we didn't expect to find.

The universe is laden with massive galaxies that formed while the universe was just one billion years old, an era when such mature galaxies were not expected to exist.

Astronomers with the Gemini Deep Deep Survey have found an abundance of galaxies in the "redshift desert," a region of space thought to be sparse because of the time needed for massive galaxies to form. But a wealth of patience, combined with long telescope exposure times, has shed some new light on the matter.

What are we using as our estimate for the age of the universe these days...15 billion years? 20? Put a few sunlike stars in those ancient galaxies and you have the potential for intelligent life developing 10 billion years ago. So multiply everything I said about a head start by 10.

Contrary to what I said earlier about whether these ancient intelligences and we would have anything interesting to say to each other, I'm reminded that John Smart (in our recent interview) suggested that we will likely never find any of these intelligent forerunners:

As I've mentioned earlier, I think all universal intelligence follows a path of transcension, not expansion. This has to do with such issues as the nature of communication in complexity construction (two-way, with feedback, is relentlessly preferred), the large scale structure of the universe (which puts huge space buffers between intelligences) and the small scale structure of the universe (which rewards rapid compression of the matter, energy, space, and time necessary to do any computation).

Once our antennas are powerful enough to detect unintentional EM emissions from the closest few million stars, something that Frank Drake tells me is almost possible now with the closest of our neighboring stars, we'll begin to discover these unmistakable signatures of nonrandom intelligence. We will also notice that every year, a small fraction (roughly 1/200th) of these radio fossils suddenly stop sending signals. Like us, these will be civilizations whose science invariably discovers that the developmental future of universal intelligence is not outer space, but inner space.

By the way — if John is right — we've got about 100 years more of broadcasting before we've finished leaving our mark in outer space. Who knows? Maybe in a billion or three years, some upstart ET-come-latelies in a distant galaxy, surprised to discover that potentially life-sustaining stars existed long before their species came about, will point their radio telescopes at the sky and catch the last few minutes of the Humanity Show.

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January 01, 2004

Farewell to Time

On this New Year's Day, why should we be content merely to say goodbye to the year just ended when we can say goodbye to the notion of time itself?

Brian Greene pens a lengthy op-ed in today's New York Times on the nature of time, and how our understanding of it has changed. According to Greene, our understanding is likely to change even more in the years to come:

Today's scientists seeking to combine quantum mechanics with Einstein's theory of gravity (the general theory of relativity) are convinced that we are on the verge of another major upheaval, one that will pinpoint the more elemental concepts from which time and space emerge. Many believe this will involve a radically new formulation of natural law in which scientists will be compelled to trade the space-time matrix within which they have worked for centuries for a more basic "realm" that is itself devoid of time and space.

This is such a perplexing idea that grasping it poses a substantial challenge, even for leading researchers. Broadly speaking, scientists envision that there will be no mention of time and space in the basic equations of the sought-for framework. And yet just as clear, liquid water emerges from particular combinations of an enormous number of H20 molecules time and space as we know them would emerge from particular combinations of some more basic, though still unidentified, entities. Time and space themselves, though, would be rendered secondary, derivative features, that emerge only in suitable conditions (in the aftermath of the Big Bang, for example). As outrageous as it sounds, to many researchers, including me, such a departure of time and space from the ultimate laws of the universe seems inevitable.

The notion of describing the operation of the universe without reference to space or time put me in mind of Julian Barbour's The End of Time, a book which purports to do that very thing. Barbour describes space and time emerging as a waveform through a vast configuration space that contains what we might think of as perfect 3D still-life renderings of the universe. Every possible configuration of the universe exists in this space, and we might be tempted to think of time as stop-motion animation. Experiencing the configurations sequentially creates the illusion of the passage of time (and of motion, which Barbour also claims doesn't really exist, at least not the way we think it does.)

These stop-motion frames start to sound a little like the flip-book picture of time that Greene refutes in his op-ed:

For example, if you and I were sitting next to each other, our freeze-frame images of the present would be identical. But were you to start walking, the mathematics of relativity shows that the subsequent pages of your flip-book would rotate so that each one of your new pages would angle across many of mine; what you'd consider one moment in time your new notion of the present would include events I'd claim to have happened at different times, some earlier and some later.

Greene's objections to a stop-motion universe are well-taken when applied to a literal freeze-frame model, although I don't think that's exactly what Barbour proposes. The freeze-frame imagery is just a handy way to visualize the ideas in approximation. I'm pretty sure that Barbour wouldn't approve of my stop-motion animation analogy, relying as it does on some notion of an external clock. In Barbour's model, there are no clocks and there is not time, nor space (as we think of it) nor motion. These are all "optical illusions" that derive from the clustering of more and less probable configurations within the configuration space.

The problem with adopting this kind of model is that it flies directly in the face of experience. It will require an enormous change of perspective — bigger even than when Galileo told us that the sun doesn't actually rise or set — for us to accept the idea that time doesn't really exist. Still, whether through Barbour's model or some other, Brian Greene seems quite convinced that this is a change of perspective we will all eventually have to make.

What better time to start could there be than the beginning of a new year?

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October 30, 2003

Stranger Than We Thought

Bruce Sterling offers a pithy yet mind-blowing assessment of what the Wilkinson Microwave Anisotropy Probe has revealed about the nature of the universe.

Already, the probe's findings have provided a few salient new notions about the nature of cosmic reality. For starters, the universe is 13.7 billion years old. Unlike previous figures, this is not a rough estimate; the margin of error is about 1 percent. In addition, the universe is flat. Forget all that mind-boggling space-time-is-curved stuff. Euclid was right all along. And the space-time pancake will expand infinitely. There's no such thing as an end to this particular universe.

Now here's the really wacky part: Everything we're made of or can measure - from atoms to energy - is only 4 percent of the whole shebang. The rest is dark matter (about 23 percent) and, best of all, dark energy (73 percent).

So what is this dark energy, anyway?

This mysterious stuff pushes the universe apart. It forces the cosmos to expand. This is not the steady state model of Einstein's heyday, when the universe was static and conservative. It's not even the jazzy big bang model, where everything blew up way back in the beginning. We denizens of the 21st century live in a steady bang. The bang never went away - in fact, our natural habitat is bang. Three-quarters of the universe is dedicated to pushing itself open. It's a gigantic heaving that has worked from the first primal instants and always will. It's the very nature of space to expand.

Whoah. What could be cooler than that? How about trying to tame it?

There's one more thing to consider: What will it take to get our atom-smashing mitts on some dark energy? This stuff is the fountainhead of the universe. It makes Iraqi oil look like a dust mote. The 21st century offers us a new quest. Dark energy is irresistible.

Read the whole thing. Interesting days lie ahead.

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October 17, 2003

Enlightening the Universe

Ray Kurzweil, in an interview in What is Enlightenment? magazine, spins a scenario by which intelligence may re-shape the universe itself:

In my mind, we will ultimately saturate all of the matter and energy in our area of the universe with our intelligence, and I suppose you could say that's an end in itself. All of this dumb matter and energy around us will wake up and become sublimely intelligent. Then it will spread out to the whole universe at the fastest speed information can flow. And one could make an argument that it's not going to take an infinitely long time because there may be other ways to get to other parts of the universe through shortcuts like wormholes, which physics has postulated. Eventually the whole universe will, essentially, wake up.

But isn't it interesting that you never see cosmologists give any role to intelligence in the future destiny of the universe? Rather, they talk a lot about whether or not the universe will contract back to a big crunch or expand indefinitely, as if these sorts of mindless forces of physics are just going to endlessly grind on like a big dumb machine.

Nowhere do they consider, "Now, wait a second, intelligence could spread through the universe and actually make an intelligent decision about what the destiny of the universe is, and even though the gravitational force and other forces might cause the universe to spin apart, the intelligent civilization infusing the whole universe will decide, 'No, we're not going to do that. We're going to do something different.'"

Such an evolutionary development will represent a confirmation or even vindication of sorts for pantheists. Those who have always believed that the physical universe is host to a divine intelligence will, in a sense, be proved right.

The intelligence will be there — in every pebble on the beach, in the birds, in the trees, in the clouds, in every star in a moonless sky — but it won't exactly be divine. It will be us.

Posted by Phil at 06:46 AM | Comments (1) | TrackBack

October 16, 2003

The Little Brown Universe

All kidding aside, this piece on brown dwarfs (for some reason I can't shake the non-sequitur that Professor Tolkien presumably would have called them "brown dwarves") is really interesting. I remember first reading about them years ago. We don't hear much about them, but they're fascinating. Consider:

Brown dwarfs are failed stars about the size of Jupiter, with a much larger mass -but not quite large enough to become stars. Like the sun and Jupiter, they are composed mainly of hydrogen gas, perhaps with swirling cloud belts. Unlike the sun, they have no internal energy source, and emit almost no visible light. Brown dwarfs are formed along with stars by the contraction of gases and dust in the interstellar medium, McLean said. The first brown dwarf was not discovered until 1995, yet McLean suspects the galaxy is teeming with them.

"Brown dwarfs are the missing link between gas giant planets like Jupiter and small stars like red dwarfs."

If large numbers of brown dwarfs exist, they "could make a small, but significant contribution to dark matter," the so-called "missing mass" in the universe, McLean said.

"Brown dwarfs won't account for all of the so-called dark matter," he said. "There is mass in the form of ordinary matter that is unaccounted for because we don't yet have the technology to find it. There are brown dwarfs, and maybe small black holes, and faint white dwarfs - regular stars that lost their outer gaseous envelopes leaving the burned-out core of old stars. White dwarfs, brown dwarfs, black holes, and gas account for some of the dark matter. The rest is presumably a new form of matter."

It's been said that astronomy is the second oldest profession. For the vast majority of human history, beginning when we lived in caves, astronomy has had to do with looking at shiny objects in the sky. In terms of human history, the notion that there's more out there that we can't see than we can is a novel one.

Brown dwarfs are now one of the suspects in The Case of the Missing Matter. They certainly raise some evocative images. What if, all along, there were as many invisible brown dots as there were twinkling white ones in the night sky? In fact, what if there were more of the brown dots? As a speculist, I'm devoted to the idea of parallel universes. Brown dwarfs provide a kind of convenient and economical parallel universe.

There could be trillions of these enormous cool worlds — or should we call them stars? — lying side-by-side with the universe we see. Suppose some form of life took hold on one of them and made its evolutionary way to intelligence. How fortunate these creatures would be if they decided to venture out into space. There's a whole universe of similar worlds out there for them to explore. So far, we can't say the same thing about our own planet. The brown-dwarfers might develop a vast intragalactic civilization, a galactic empire from which the bright stars and stony micro-planets that we think of as making up "the universe" would be viewed as an interstitial backwater. Pretty, perhaps, and even kind of mysterious, but having no real significance when weighed against the real universe.

Posted by Phil at 06:04 AM | Comments (0) | TrackBack

October 10, 2003

The Soccer-Ball Universe Debated

I never got around yesterday to writing about this new theory that states that the universe is a sort of big, mirrored soccer ball that only kind of looks likes it's infinite because of all the reflecting surfaces.

In a paper being published today in the journal Nature, Dr. Jeffrey Weeks, an independent mathematician in Canton, N.Y., and his colleagues suggest, based on analysis of maps of the Big Bang, that space is a kind of 12-sided hall of mirrors, in which the illusion of infinity is created by looking out and seeing multiple copies of the same stars.

If the model is correct, Dr. Weeks said, it would rule out a popular theory of the Big Bang that asserts that our own observable universe is just a bubble among others in a realm of vastly larger extent. "It means we can just about see the whole universe now," Dr. Weeks said.

Well, already the idea is taking some (it's not my pun; blame the NYT) sharp kicks.

If the model is correct, Dr. Weeks said, it would rule out a popular theory of the Big Bang that asserts that our own observable universe is just a bubble among others in a realm of vastly larger extent. "It means we can just about see the whole universe now," Dr. Weeks said.

Why it matters so much:

The stakes for cosmology, should the soccer ball or some other variety of small universe prevail, are not small at all. A small universe, everybody agrees, would present severe problems for the prevailing theory of the Big Bang, known as inflation, which posits that the cosmos underwent a burst of hyperexpansion in its first moments.

Moreover, Dr. Weeks said, a small universe would eliminate one popular variant of the theory known as eternal inflation, in which bubble universes give rise to one another endlessly in what some cosmologists call a "multiverse."

"This puts the whole universe in view," he explained. "It wouldn't rule out other universes. There could be others. They would be totally unrelated, without any contact between them."

I just find it surprising that this could even be the subject of debate. Hasn't the shape of the universe already been established to everyone's satisfaction?

Posted by Phil at 07:43 AM | Comments (1) | TrackBack

August 11, 2003

Did We Create the Universe?

From Kenneth Silber's Tech Central Station column:

Has an Oregon lawyer discovered the secret of the universe?

Gardner's hypothesis is called the "Selfish Biocosm." It states that intelligent life plays a key role in a cosmological cycle whereby the universe, over enormous timescales, creates new copies of itself. The laws of physics, in this view, strongly favor the emergence of life and intelligence -- and indeed are designed to do so.

But how did the cycle begin? Isn't there a gigantic chicken-and-egg problem? One might suppose the first universe containing intelligent life arose by accident, perhaps as part of an ensemble of universes that were mostly unfriendly to life. But Gardner regards this as an unsatisfying explanation. Rather, he proposes a notably strange idea. There may be a "closed timelike curve," a gravitational warping of space and time such that future events can influence the past. Thus, the universe may have been created by its own inhabitants!

This is an interesting idea. A while back we took a look at the idea that maybe inhabitants in one universe create other universes. Merge these two ideas and you can come up with something like Escher's Drawing Hands. Maybe inhabitants of another universe created our universe and so, when the right time comes, we'll return the favor by creating their universe.

via Rand Simberg

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July 22, 2003

Are We Living in the Matrix?

Or maybe it would be fairer to say that our universe is a vast Holodeck.

In a detailed Scientific American article, physicist Jacob D. Bekenstein describes how our universe could be a holograph "painted on the edge" of a higher-dimensional universe:

Using anti-de Sitter spacetime, theorists have devised a concrete example of the holographic principle at work: a universe described by superstring theory functioning in an anti-de Sitter spacetime is completely equivalent to a quantum field theory operating on the boundary of that spacetime [see box above]. Thus, the full majesty of superstring theory in an anti-de Sitter universe is painted on the boundary of the universe. Juan Maldacena, then at Harvard University, first conjectured such a relation in 1997 for the 5-D anti-de Sitter case, and it was later confirmed for many situations by Edward Witten of the Institute for Advanced Study in Princeton, N.J., and Steven S. Gubser, Igor R. Klebanov and Alexander M. Polyakov of Princeton University. Examples of this holographic correspondence are now known for spacetimes with a variety of dimensions.

This result means that two ostensibly very different theories--not even acting in spaces of the same dimension--are equivalent. Creatures living in one of these universes would be incapable of determining if they inhabited a 5-D universe described by string theory or a 4-D one described by a quantum field theory of point particles. (Of course, the structures of their brains might give them an overwhelming "commonsense" prejudice in favor of one description or another, in just the way that our brains construct an innate perception that our universe has three spatial dimensions; see the illustration on the opposite page.)

For all my Matrix and Holodeck language, it's important to note that Bekenstein seems to be talking about a mathematical relationship that would exist naturally. But I'm not sure he addresses the issue directly. Sure a universe can be holographically painted on the edge of a different kind of universe occupying different dimensions, but how would this happen?

Who did the painting?

Maybe that's just how universes work. Perhaps the higher-level universe is just the first in an infinite series of turtles' backs.

Or maybe somebody made it happen. Perhaps some intelligence in a 5-D anti-de Sitter universe looked "up" (we're talking five dimensions, here, so I have to be cautious when talking about directions) and said to one of her associates, "Say, did you ever notice that we could put a whole little universe right there on that boundary? Wouldn't that be neat?"

And so here we all are. Not the Holodeck, not the Matrix. Just a sort of cosmological equivalent of the paint job my wife and I did on our bedroom over the weekend. To be fair, I guess putting our universe in place would have been more like installing an aquarium than like painting a room, but you get the idea.

I don't mean to be flippant. And I don't mean to suggest that it was easy. (Actually, have you ever tried to put in an aquarium?) The technology to paint a universe holographically on the edge of our own universe is far beyond our current capability. We're only coming to terms with the idea that such a relationship between universes is possible. Moreover, it might not be something that you can do from within a given universe. Maybe the ability to holographically project a 4D universe onto a 5D universe is only available in, say, a 9D universe.

For some reason, this whole idea reminds me of Roger Zelazny's The Chronicles of Amber. In the Chronicles, there was one real world, Amber, which cast an infinite number of parallel-universe "shadows." Our own universe was one of the shadows. Now, we all tend to think of our universe as being real.

I mean, obviously.

But the Amberites didn't see it that way. Shadows were just shadows; some were more like Amber than others, and were therefore more real. Others tended off in the direction of Chaos, and were therefore less real.

Perhaps that's how the higher-dimensional interior designers would view us. Interesting, even amusing, but not really real.

(via GeekPress)

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