Tuesday, February 04, 2014

The Latest on Time Travel. An ironic title for news about weird S**T

All right, this is going to get a bit dense and weird, as we glimpse discussions of time travel.  But first... a string of wonderfully interesting bits of science news!
== Is each neuron a quantum computer? ==

neuron-computerThe recent discovery of quantum vibrations in microtubules inside brain neurons appears to corroborate claims that consciousness derives from deeper-level, finer-scale activities inside brain neurons. The eminent mathematical physicist Sir Roger Penrose in the 1990s suggested that quantum vibrational computations in microtubules were “orchestrated” (“Orch”) by synaptic inputs and memory stored in microtubules.  They may be the seat of stored information that neurons (and glia exchanges) intermediate.  Moreover, in a new development it is thought that Microtubule quantum vibrations (e.g. in the megahertz frequency range) appear to interfere and produce much slower EEG “beat frequencies.”
In Consciousness in the universe: A review of the 'Orch OR' theory, Penrose and Hameroff suggest, “Consciousness depends on anharmonic vibrations of microtubules inside neurons, similar to certain kinds of Indian music, but unlike Western music, which is harmonic."  

How cool and weird!  Only I am less interested in the mystical implications about roots of consciousness than whether this nails in "intracellular computing" as a major part of brain function. 
If so, then that boosts by many orders of magnitude how many transactions take place to comprise our minds.  And many more Moore's Law doublings will be needed before that number can be replicated, in silicon.
Is that good news or bad news?  Will this delay the arrival of friendly machines who will solve our problems and help us become better, too?  Or will it save us from the imminent arrival of Terminator/Skynet, giving us time to ponder how to do these things right, as physicist Max Tegmark proposes in his article, Humanity in Jeopardy on the Kurzweil site -- as well as his book, Our Mathematical Universe.
the-second-machine-age-cover-259x394Where are we headed? These tradeoffs are discussed by Erik Brynjolfsson and Andrew McAfee in their new book, The Second Machine Age: Work, Progress, and Prosperity in a Time of Brilliant Technologies.

And, of course, well… I explore them pretty extensively, too. See my earlier posting: Could Our Universe Be a Fake?
== Why Glass is so limited? ==
What are the design tradeoffs in delivering actual immersive augmented reality glasses, of the sort I called "tru-vu goggles" in EARTH (1989)? Google Glass finesses the problem with a very narrow angle of view, offset from straight-ahead.  In this article you can see some of the problems… and how a new company has come up with clever ways to solve them.
At Google last week, I described to Head of Research Peter Norvig the reasons why I thought Google was keeping Glass simple, and not covering the user's visual field, or offering face recog features.  He said yep. The company with big pockets cannot afford to be the first to offer full Augmented Reality.  Not when the first ten years will be (as I describe in fiction) filled with accidents and lawsuits.
== What I learned while visiting tomorrow ==
All right then…  David Deutsch, a pioneer of quantum computing and a physicist at Oxford -- as well as the author of The Beginning of Infinity -- came up with a simplified model of time travel to deal with the Grandfather paradox*.  He solved the paradox originally using a slight change to quantum theory, proposing that you could change the past as long as you did so in a self-consistent manner.
clone-information-past“Meaning that, if you kill your grandfather, you do it with only probability one-half,” said PRL co-author Mark Wilde, an LSU assistant professor. “Then, he’s dead with probability one-half, and you are not born with probability one-half, but the opposite is a fair chance. You could have existed with probability one-half to go back and kill your grandfather.”
The original article cited here maintains that, to be consistent with Deutsch’s model, which holds that you can only change the past as long as you can do it in a self-consistent manner, Wilde and colleagues had to come up with a solution that would allow for a looping curve back in time, and copying of quantum data based on a time traveling particle, without disturbing the past.
“That was the major breakthrough, to figure out what could happen at the beginning of this time loop to enable us to effectively read out many copies of the data without disturbing the past,” Wilde said. “It just worked.”
“If an adversary, if a malicious person, were to have access to these time loops, then they could break the security of quantum key distribution,” Wilde said. “That’s one way of interpreting it. But it’s a very strong practical implication because the big push of quantum communication is this secure way of communicating. We believe that this is the strongest form of encryption that is out there because it’s based on physical principles.”Such encryption is believed to be unbreakable — that is, as long as hackers don’t have access to Wilde’s looping closed timelike curves.
=== So?  Are we being visited from the future? ===
EVIDENCE-TIME-TRAVELERSIn a recent paper, Robert J. Nemiroff and Teresa Wilson, suggest that we actually search for time travelers… via Internet searches, by seeking a prescient mention of information not previously available. Their first search covered prescient content placed on the Internet, highlighted by a comprehensive search for specific terms in tweets on Twitter. The second search examined prescient inquiries submitted to a search engine.  Whereupon, lo and behold… "no time travelers were discovered." Although these negative results do not disprove time travel, given the great reach of the Internet, this search is perhaps the most comprehensive to date.
Well, well, didn't the authors kind of assume that the time travelers either want to be found or else that - when back home in the future - they failed to do a web search for traps like the one laid by Nemiroff and Wilson?
OpenLetterAlienLurkersIt reminds me of the "Invitation to Extra-Terrestrial Intelligences" that was issued on the internet by the late professor Allan Tough, who felt certain that mechanical envoy-lurkers -- waiting in the asteroid belt for millions of years -- had already inveigled their way into our networks to read our web pages. (And much more? Are there NSAliens out there?)  Further that they were only awaiting an invitation to speak up and announce themselves.  Allan was brave enough to invite me to post my own variant (deviant?) invitation… or else decryption of why lurkers might refrain and just keep lurking.
All the same logics apply to time travelers, I'm afraid.  Oh, that invitation of mine to lurkers?  It became a number of chapters in Existence!
For an exploration of time travel scenarios in science fiction, see an extensive list of Time Travel in Fiction, or the more recent anthology The Mammoth Book of Time Travel SF, with short stories by Silverberg, Rusch, Levinson, Swanwick, Priest and others.
== And finally ==
Two newly discovered species of spider -- in far-apart Peru and the Philippines -- make decoy spiders to place on their webs, each one about the size of a half-dollar, constructed from debris and food carcasses, with eight legs radiating from its bulky center. The tiny sculptor dwells inside her creation.
Batteries will be vital in the new world of dispersed and sustainable power systems. The prospect of low-cost storage has long been a nirvana for the renewable energy industry with the intermittent nature of wind and solar energy restraining their competitiveness against fossil fuels such as coal.  Now researchers have found ways to use cheap/abundant materials in Flow Batteries.
Coolest commercial mini-drone I've seen so far.


Stefan Jones said...

I occasionally have thought, somewhere between wonder and despair, that goes something like:

"How strange, and discouraging, to live in a time when we're discovering (quantum effects in brain cells!) and creating such cool stuff, yet a significant chunk of the population doesn't believe in evolution, thinks global warming is a conspiracy by scientists to make money, and are convinced that the snow in Georgia is an artificial substance created by 'chemtrails' as part of a sinister government plot."

And then I remember:

It. Has. Always. Been. This. Way.

What is different is that there are now the means, and the commercial motivation, for (sorry) ignorant and superstitious people to have a voice.

Crazy ranting and conspiracies were once the thing of mimeographed newsletters and rallies of hooded back-country ignoramuses. Now, theya re something something that radio shows, web sites, and cable TV channels can profitably cover.


When someone rants about how America's high school students were once better educated than today's college grads, what is left out is the fact that less than 20% of the population went to high school, and a very large portion of the population stopped their schooling after "grammar school" (3rd grade) to work in factories and fields.

One of the successes of public education is that it includes and makes visible a large swath of children who, thanks to a variety of issues, once weren't considered worthy of higher education. And because there was a big demand for unskilled labor, they didn't have to be educated.

Damned if I know what can be done about the Commodification of Dumb and the challenges of education in a broad democracy. But I do know that the way things are now isn't cutting it.

Mark said...

If so, then that boosts by many orders of magnitude how many transactions take place to comprise our minds. And many more Moore's Law doublings will be needed before that number can be replicated, in silicon.

Perhaps not. Estimates of required brain capacity I've seen depend upon the understanding of the back of the eye. Line detection and other preliminary visual functions happen right in the back of the eye. This is apparently one of the most understood parts of the brain. Fortunately, this functionality is also a well understood computation we can reproduce. Thus, comparing the ability of the neurons in the back of the eye to needed computer power to reproduce we can get an estimate of total brain power in computational terms.

So perhaps the estimates are still valid.

On the other hand, line recognition ain't consciousness. Perhaps the back of the eye doesn't use the quantum level, intracellular computing, so the direct comparison isn't valid.

A quick google found this document: http://www.frc.ri.cmu.edu/~hpm/book97/ch3/retina.comment.html

Unknown said...

Hello David and Brin Blogees,

It was a fun project, and we searched for what we could. The challenge I posed my students was: assuming time travelers are among us, how would you go about finding them? Many enjoyed the challenge because, as you cite, there is a lot of science fiction involving time travel. Any better ideas anyone? 

Yes, as we state right in the paper and as you correctly point out, if time travelers don't want to be found and are good at covering their tracks, they can go undetected. So much for one of the premises. But I, for one, keep making mistakes, so not only would I be a lousy time traveler, I keep inadvertently giving away the ending to movies I've already seen. (To say nothing of the dog.)

locumranch said...

I used to be partial to Time Travel stories, especially those of Clifford D. Simak, until I realized that the entire time travel concept was based on linguistic error, the confused equivocation of a name for a thing and a thing for a positional place, because the so-named ‘past’ (being the recollection and/or memory of a transient entropic state) is neither thing nor place.

And, equivocate is exactly what Deutsch does in an attempt to resolve the Grandfather’s Paradox, nattering on about a “1/2 probability” in the past tense, even though any elementary school fool can tell you that partial probability only applies to future events as in ‘The probability of a prior coin flip can be predicted with a 100% probable certainty since that outcome has already happened in a known Past’ and ‘The outcome of a pending coin flip can only be predicted with a 50% probable certainty until it has achieved 100% certainty in a known Future’.

Wilde demonstrates similar semantic ignorance when he talks about Quantum Particles ‘circling into the past’ because the Past (being the name we give our recollection of entropic transience) is neither a place nor a thing in any material sense and, lacking even the pretense of physicality, it cannot be ‘visited’ or ‘revisited’ in a non- metaphorical manner, nor can it be said to even ‘exist’.

This is also why I so despise the present incarnation of Quantum Mechanics, a theory which starts out well and reasonable with honest calculations of probability, veers off course into an extended literary analogy about cosmic strings, negative probabilities, imaginary number sets & multiplex universes, and then emerges as an insupportable philosophy adorned with a pseudo-scientific glamour.

The past, the substrate;
the future, the product;
the reaction, an energy gradient;
our time sense, a perception thereof.


locumranch said...

Or, better yet ...

The past, the substrate;
the future, the product;
the present, an energy trade;
reactive time, our perception thereof.

Acacia H. said...

Except, Locum, if you traveled to the past, the past becomes the present and future and is able to thus be manipulated on a quantum scale.

The alternative is the theory of time as a hologram. Everything has happened and will happen in one instant. But as we travel through the holographic illusion of time, we are given the perception of a one-way trip through time, despite the fact everything happened at the same instant and we are all bugs frozen in amber in that one moment of time. The final death of the universe, the initial burst of its birth, the formation of the Earth, its death when the sun swells into a Red Giant, even yesterday's lunch all happened now. You just cannot perceive of it as you are in the amber.

Rob H.

Paul451 said...

Re: Time Travellers.

The search can't rule out the time-travellers retro-preventing their own mistakes. Going back and removing the offending term or tweet after-before the searcher detect/will-detect/detected it. They don't have to be very good, just reverse/prevent the mistakes that are/will-be actually detected.

Hence the search will only detect careless trapped time travellers. Those accidentally sent back. (Like the many "do over" movies and occasional TV shows.)

Tim H. said...

One might be able to exchange a "Here & now" for a different one, that was originally a "There & then", that would become your "Here & now". I suspect a traveler to our present might learn much by lurking online and downloading a wikipedia mirror, too much to be hoped that they'd misplace their iPhone 42 or galaxy S37...

atomsmith said...

Why continue search for time travelers? We already found one!

Jumper said...

Here's an oddity of a story I had been unaware of until yesterday.

locumranch said...

Thanks, Rob, for providing excellent examples of unspoken metaphorical argument masquerading as scientific empiricism:

(1) ‘If you traveled to the past (as if time was ‘like’, comparable or identical to a material destination), (then) the past becomes the present and future (??)”.
(2) ‘The alternative is the theory of time as (if it were comparable to) a hologram …’.
(3) ‘But as we (metaphorically) travel through (time as if it approximated a) holographic illusion … we (might be) given the (conditional) perception of a one-way trip through time despite the (assumed; unconfirmed) fact everything happened at the same instant …’
(4) ‘We are all (like, similar, comparable or identical to) bugs frozen in amber in that one moment of time (in which we assume that everything happens simultaneously, so) you just cannot perceive of it as (if) you are (the equivalent of a bug trapped) in the amber’.

Unfortunately, all of your subsequent conclusions (including your apparent attachment to quantum nonsense) do not follow logically as (1) time is neither a thing nor a material place, (2) the memory of an occurrence is non-identical to an actual occurrence; (3) there is no empiric evidence to suggest that time is holographic even though human memory may be; and (4) metaphorical argument is a poor logical substitute for empiricism.


Gator said...

Re Penrose et al.
You seem to have a much higher tolerance for hand-waving and science than I.

This is still more of "We don't understand X, and we don't understand Y, so how about I just say they are related."

This is all based on the "measurement problem" which is not really a problem. Declaring it a problem means you have to abandon causality and relativity and make some sort of real physical explanation for how a quantum entangled particle can transmit its state instantly over arbitrary distances.

David Brin said...

Thanks for dropping by Dr.Nemiroff. Your study reflects the kind of fun thinking and new use of Big Data that will propel the age of amateurs... and the age of empowered transparency.

Loads of fun!

Paul451 said...

A clever bit of detective work suggests that the asteroid Itokawa (peanut shaped rubble-pile imaged by the Hayabusa probe) is made up of two parts of distinctly different densities, the smaller part about 60% denser than the larger.


Most likely the result of a smooshy collision between two asteroids.

David Brin said...

This is why we keep locum around. Sure, he keeps doing the same thing... using armwave polemic to accuse others of armwave polemic. But this time he was both somewhat persuasive and very eloquent!

Unknown said...

I was quite surprised to see the time-travel topic. I had just popped H.G. Wells' "The Time Machine" into the DVD-player while waiting for this page to open up.

I've never really bought into the "grandfather paradox." I've always thought of time as like a river. Rivers meander and overflow their banks, eroding new passages from the substrate. Going back to the past would not necessarily take you to your own past but a different one.

David Brin said...

lousy slouch... you'd like my story "The River of Time...."

Jim H. said...

One of the characteristics of pseudo-science is the appeal of thinking wouldn't it be great if that were true. I hate to see Hameroff and Penrose featured on your page because their theory has been searching for evidence for a long time (the tubule hypothesis is a decade old). If you actually look past the dressed up techo-babble, it is hard to find a "there" there. Commenters on the paper you link to are clear that this 'research' is not consistent with the scientific method. Complex fictional 'science' does not progress make.

Unknown said...

Thanks for the suggestion David. Order has been placed.

Oh and it's sloth not slouch : )

Alex Tolley said...

I'm with those who consider that Hameroff and Penrose's theory of consciousness is just so much bafflegab. If it was true, wouldn't this just delay Kurzweil's forecast timeframe of AGI?

I don't see Deutsch as having advanced anything regarding the possibility of time travel. While the quantum world allows for time reversal, that doesn't mean that this applies at the macro level. Newer ideas that use entropy to ensure events move in one direction seem more reasonable to me. Relativity allows a form of time travel to the future, but I see nothing to really allow time travel to past, and logical paradoxes don't really cut as much more than a party trick. Looking for time travelers from the future is not unlike SETI (beings are out there, we just can't see them), but without even a veneer of plausibility.

If time travel to the past was possible, this could mean stellar distances are not a barrier to starflight or communication. So where are the galactic empires? It would also mean that we have no future stellar future. Again where are the human galactic empires?

Flow batteries are a fascinating energy storage technology. I think they are well suited to electric cars as the infrastructure is already in place - just replace gasoline with fresh electrolyte at the pump. I'm less sure about home energy storage, but the possibility of energy delivery by electrolyte might be a game changer.

Alfred Differ said...

The classical world doesn't really object to time reversal either. People get too hooked on the idea that there is an entropy issue, but I don't see it. Entropy says more about how much control you have over the microstate of a system relative to agreed upon macrostates than anything else. We make up the macrostate definitions. Nature doesn't really have to care that a bazillion different detailed arrangements of atoms in a box lead to the same pressure measurement while two bazillion states lead to a slightly different pressure. If we can't measure the details (let alone control them) we will observe the macrostates that are most likely and perceive trends. Nature doesn't have to care how we see it all.

Wheeler and Feynmann showed how a classical theory could violate causality at the detail level and not appear to do so at the larger level and didn't rely on quantum to do it. It's just a matter of recognizing that there are other solutions to radiation equations besides the 'retarded' ones. We can use superpositions of advanced and retarded solution and the physics still works. If there is one thing I learned from quantum theory it is that when two approaches produce indistinguishable results, it is best to assume the assumptions that distinguish the theories are probably illusory. Set them aside and see if one can make sense of what is left.

Robert Sandstedt said...

I view the difficulties of time and interstellar travel as different scales of the same hurdle. In order to do either, human beings need to last long enough, or the laws of physics need to be adjusted to allow for movement at the speeds necessary, to get where we want to go in our current lifespans.

Alex Tolley said...

@Alfred The classical world doesn't really object to time reversal either.
Wheeler and Feynmann showed how a classical theory could violate causality at the detail level and not appear to do so at the larger level and didn't rely on quantum to do it.

Do you have an accessible reference for this (something that doesn't require a physics degree to understand)?

locumranch said...

As evidenced by our discussion of 'time travel', many of our most treasured scientific theories rely and are based on extended metaphor (which does not necessarily imply that they are either invalid or false) but does suggest that they are exceptionally vulnerable to both misinterpretation & fallacious logic, a point that I have tried to communicate again & again, often failing miserably, especially in the cases of social policy, climate change & quantum theory. To this end, I have referenced a few important articles (listed below) which, if given the opportunity, should clarify my argument regarding the mythic irrationalities of language, society & science:

(1) 'Position paper on metaphor,' by Lakoff, at

(2) ‘Metaphor in Science,’ by Hoffman, at

(3) 'Metaphoric Fallacy to
a Deductive Inference', at

(4) ‘Metaphors we live by’, by Lakoff and Johnson, at
‘Metaphors we live by’, Lakoff and Johnson


David Brin said...

geeez Mr. never-appeal-to-authority sure don't follow his own advice...

Paul451 said...

"I'm less sure about home energy storage, but the possibility of energy delivery by electrolyte might be a game changer."

Being able to store solar power at your home will make solar panels that much more useful. Being able to store off-peak grid-power at your home for use during peak times will dramatically improve the efficiency of the grid (reducing peakiness.) Being able to store off-peak wind and solar power at large generator sites for use during peak (or night/calm weather) makes alternative suppliers more profitable and more reliable. Being able to store power at every sub-station makes the whole grid more reliable. Being able to truck charged electrolyte to storm-isolated sub-stations, businesses, even homes after natural disasters is kind of cool too. [And, of course, being able to "recharge" electric cars by refueling via a bowser-pump at any service station fundamentally changes the whole "range-anxiety" thing.]

Flow batteries are cooler than conventional (cell) batteries because it separates the "capacity" from the "supply rate". To increase the storage capacity, you only need bigger tanks, not more cells. If you can get the price of the electrolyte down, you drastically reduce storage costs for these kind of large-scale applications, even if you don't reduce the cell-costs. I've had my fingers crossed for flow-batteries for years.

"If time travel to the past was possible, this could mean stellar distances are not a barrier to starflight or communication."

Interesting observation.

"Again where are the human galactic empires?"

Perhaps they existed "a long time ago"? :)

Alfred Differ said...

@Alex Tolley:

I don't. Sorry. They way I came to learn this was in conversations with my graduate advisor who was deeply impressed with Feynmann's talent for creative thinking. Without the discussions, I'm sure I would have missed this early work and easily missed the meaning behind it even if I had accidently tripped across the papers. Imagine going to an art museum with a talented artist who could explain some of what you were seeing. You get a very different experience that way than you would going on your own.

The nutshell version, though, is that the wave equations permit solutions we usually don't use. It's like when we reject negative solutions to certain problems involving motion. If you want to know how long it will take before a certain collision occurs and get two answers (negative and positive) you can reject the negative one based on the fact that you want a future solution. The equation produces both, but your problem has further constraints. It is possible we have added causality as a 'further constraint' when we don't really need to. The equations certainly aren't forcing us to do it within classical field theory anyway. 8)

Keith D. Halperin said...

RE: New low-cost, high-energy batteries could be powered by rhubarb, plants
Perhaps we'll know they're getting somewhere when we read one or the other of these scenarios:

1) Chinese, Saudis, Koch Nrothers buying up rhubarb farms worldwide or

2) Mysterious plant disease decimating rhubarb harvests- cause unknown...

Jumper said...

A pioneer in nastiness, Joe Pyne was on the radio and TV some time ago. Unfortunately.

Jumper said...

I am fond of the idea that the past is just as fluid as the future. If the past was morphing constantly, there is no reason we would know it: our present would be changing too.

Alex Tolley said...

Perhaps they existed "a long time ago"?

But then all they need is a vanilla relativistic starship to slow time and travel into the future and start the next colonization wave and empire. There should be Galactic empires all around us.

Paul451 said...

It was just a Star Wars joke.