Neutrinos caught speeding!

The big news in physics at the moment is that a beam of neutrinos from CERN has turned up at a particle detector 60ns sooner than should have been physically possible. Did they really travel faster than light? At first glance, most scientists would say that there's probably a flaw in the measurements somewhere, but the team who made the discovery had spent 2 years checking the results before they published them. However, if neutrinos really were travelling faster than light, we should have detected neutrinos from a supernova 5 years before the light from the explosion. (What if some did arrive that early and nobody noticed?) More exotic theories are going about. According to some versions of string theory, the universe we know is a four dimensional strcture called a brane (short for membrane) embedded in a higher dimensional bulk. If the brane is slightly curved, neutrinos could take a short cut across the bulk.

So, have we found an exception to relativity? Is this evidence of extra dimensions? Or will it all come down to experimental error? I know that the latter is most likely, but I want my spaceship!

Quantum Thinking and Function Words

Two articles in New Scientist caught my eye this week - one about a quantum mechanics like system of logic and the other about function words. According to the first article, many of our thought processes don't follow the rules of classical logic, but a system of inference that can be described in terms of Hilbert Space, which is a vector space with an arbitrary number of dimensions. Quantum mechanics uses Hilbert spaces to describe the states of quantum systems, and the mathematics of Hilbert space allows quantum states to interact in counter-intuitive ways. The same logic apparently allows human minds to combine ideas in ways that don't necessarily follow the rules of classical logic, but do allow greater flexibility. To quote from the article -

If you want to research a topic such as the "story of rock" with geophysics and rock formation in mind, you don't want a search engine to give you millions of pages on rock music. One approach would be to include "-songs" in your search terms in order to remove any pages that mention "songs". This is called negation and is based on classical logic. While it would be an improvement, you would still find lots of pages about rock music that just don't happen to mention the word songs. Widdows has found that a negation based on quantum logic works much better. Interpreting "not" in the quantum sense means taking "songs" as an arrow in a multidimensional Hilbert space called semantic space, where words with the same meaning are grouped together. Negation means removing from the search pages that shares any component in common with this vector, which would include pages with words like music, guitar, Hendrix and so on. As a result, the search becomes much more specific to what the user wants.

Obviously, if you're interested in Artificial Intelligence, where a key aim is to enable computers to emulate the flexibility of human thought, this is a useful approach. The second article, by James W. Pennebacker, concerns his work on the importance of function words. These are things like pronouns, conjunctions and prepositions, the words that don't seem to mean very much, but act like glue holding the sentence together. Professor Pennebaker has discovered that there's a lot of psychological information hidden in these apparently insignificant words - for example, in a conversation between two people, the more socially dominant one will tend to use the word "I" less than the other one. Most natural language processing software treats words like this as stop words and ignores them, but for some applications (eg sentiment analysis, social network analytics) it could be just the data you need.

Doctor Who: The Almost People

The Almost People is a tale of humanity lost and found. As Jen, the Ganger we had most sympathy with last week is driven by her desire for revenge to become more and more monstrous, Cleeve, the human who was most monstrous last week, acknowledges her vulnerability and comes good. The other Gangers reluctantly agree to Jen's plan to destroy the humans, believing it to be their only chance of survival.

The Doctor trusts his Ganger immediately, but Amy finds she can't. She does, however, confide in him about the future Doctor's death, possibly hoping that it was the Ganger who died. She also tells the Doctor about Weird Eyepatch Woman, although the Doctor initally dismisses this as "just a Time Memory". Rory finds two Jens, and a fight breaks out between them, ending with one of them falling into a pool of acid and dissolving, revealing her to be a Ganger. When the surviving Jen shows Rory the pile of discarded Gangers, we are reminded that the Gangers do have a genuine grievance against the humans, but then we discover that the real Jen is dead. Her Ganger, having created another Ganger of herself for the purpose of destroying it to trick Rory into helping her, has crossed a line even by her own standards.

Rory and one of the Doctors have been captured by the Gangers, and base is heading for destruction, with the remaining Doctor and the surviving humans strugging to contain the acid, when Adam's son phones for his birthday. Adam's Ganger goes to get his original, only to find him dying. Being the Human who found it easiest to identify with his Ganger, Adam then hands his life over to his duplicate. The other Gangers no longer support Jen, and help the surviving humans to escape.

At the end, some of the survivors are humans and some are Gangers. We discover that the Doctors had switched boots earlier, so presumably the real Doctor knows about his assasination now. Although the Ganger Doctor and the Ganger Cleeve were dissolved stopping the now completely monstrous Jen, the possiblity that they could reconstitute themselves is left open. But ther's a bigger revalation left to come.

You remember there was a thowaway line last week about how the Flesh could even duplicate clothes? Well, I'd been wondering for a while why Amy, who loves dressing up, had been wearing the same outfit all season. It turned out that since Day of the Moon, the Amy we've been seeing has been a Ganger, and that the real Amy was being held prisoner somewhere. This explains why the Tardis couldn't decide whether she was pregnant or not - the Ganger wasn't, the real Amy was. Now, she's about to give birth, while held captive by the Weird Eyepatch Woman.

By the way, did anyone else think that the episode titles should have been the other way round?

Doctor Who: The Rebel Flesh

The Rebel Flesh brought an unusual element of hard SF into Doctor Who. Programmable matter is an idea that nanotechnologists are actively working on. It's role in the story was to explore the familiar idea of artificial people - here, the "Gangers" (short for Doppelgangers were being used to undertake hazardous work (mining deadly acid) as a safety precuation for their human operators. The opening scene brought home how this could dehumanize the operators - when a Ganger falls into a vat of acid, his colleagues are more concerned about the loss of his protective suit than him - and at this point, we don't know that he's a Ganger.

The Doctor is clearly up to something - he's planning to drop Amy and Rory off for chips and deal with this one himself. It also becomes apparent later in the episode that he already knows something about The Flesh, and isn't telling anyone what. Having bluffed his way into the facility with the Psychic Paper (a device that's being used more sparingly of late), the Dcotor inspects The Flesh in its vat, and it inspects him. After the rather creepy sight of a Ganger being created, we get the solar storm that knocks everybody out, ruptures the acid pipes, and makes the Gangers independent of their originals. The Frankenstein reference is obvious, but it reminded me more closely of Short Circuit.

The Gangers now have all the memories of their human originals. As Rory gets to know Jen, we find that they are frightened and confused. So are the humans, who at first think of the free Gangers as nothing but a threat. The Doctor introduces the Gangers to their originals, and at first it seems that there's some sort of understanding developing between the Gangers and the humans. But as in The Hungry Earth and Cold Blood, somebody has to go and ruin everything - in this case it's Cleeve, the leader, who electrocutes one of the Gangers - I think. Since the Gangers look identical to the Humans at this point, it could easily have been a Ganger killing a Human, a Ganger killing a Ganger or a Human killing a Human. At this point, our sympathies lie very much with the Gangers, but as Ganger Jen, the one that we have most empathy with, encourages her fellows to rise up in revolt, the waters become considerably muddier. The humans try to barricade themselves into the safest part of the base, but Rory is left outside, and in with them is a Ganger... of The Doctor.

All the ingredients in this story are familiar - artificial humans, a base under siege, a conflict that The Doctor tries to prevent but can't, sympathetic monsters and unsympathetic humans, The Doctor being cut off from the Tardis, the duplicate of The Doctor. It's the way they've been mixed that comes off really well in this story.

One last detail... Amy saw the weird woman with the eyepatch again.

Fortieth post Wordle

Well, we can see what I've been writing about recently, can't we?
Two interesting things to note - one is that The Doctor's Wife seems to dominate the Doctor Who related writing - I ended up writing quite a big post about that one. However, I'm glad to see that Doctor Who isn't sqeezing everything else out.

Guess what my next post's going to be about?

Robots invent a language

IEEE Spectrum describes an interesting experiment in artificial intelligence and linguistics. Two robots, equipped with microphones and loudspeakers to talk to each other, managed to create a set of words useful for navigating their environment.

I think it would be interesting to extend this experiment to see if it could give insight into how language evolves. Starting with a larger population of robots, you could give them time to make up a language, and then start deleting the memories of individual robots at intervals. In real life, languages have to be continually relearned by sucessive generations of speakers, and this is probably part of the reason why the undergo changes. It would be possible to vary the size of the population and the rate of deletions to see what influence these might have, and also to add varying amounts of background noise.

Mind you, to give a real insight into the development of human language, you might want to give the robots more complex tasks to do than simply finding their way around, so that they would have to invent a grammar to express their meaning. Then you would be seeing how language might develop in a mind fundamentally unlike a humans. There's been considerable debate amongst linguists about how many of the constraints on human languages are hard-wired into the human brain, and how many are simply a result of circumstance, and what can evolve from what already exists.

Doctor Who: The Doctor's Wife

The titleThe Doctor's Wife turned out to be a metaphor, but it was an apt one. You can well imagine hardcore fans debating who might be the greatest love of The Doctor's life. Was it Susan's grandmother? Was it Sarah Jane Smith? (RIP Lis Sladen) Was it Romana? Was it Rose Mary Sue Tyler? Was it Madame de Pompadour? Is it River Song?

No, it's the Tardis. Obvious when you think about it.

The episode has a sinister opening, with Uncle, Auntie and Nephew (an Ood) preparing Idris to have her soul sucked out and replaced with another one. Cut to The Doctor, Amy and Rory in the Tardis, bantering about past adventures. There's a knock on the door. They're in space. The Doctor opens the door and finds a message capsule from another Time Lord, "The Corsair". The message leads them to a junkyard world in a pocket universe, where the Matrix is sucked out of the Tardis.

It turns out to be a trap of course - while The Doctor searches for other survivors of the Time War, he sends Amy and Rory back to the Tardis and locks them in. He then discovers that House, the planet they are on, is a sentient planet that eats Tardises, and that The Corsair has been killed and his body parts used in House's patchwork servants. Meanwhile, House having heard from The Doctor that his Tardis is the last one left, has decided to hijack it and head for our universe in search of more food. But The Doctor has an ally - Idris, who has become a personification of the Tardis.

Neil Gaiman makes good use of Doctor Who's past in this story, pulling off the trick of using references to previous adventures in such a way that they add something if you know the reference, but don't take anything away if you don't. The Tardis comes across as pleasingly barmy, and the idea that she wanted to see the universe, so she stole a Time Lord and ran away is a neat symmetry. Best quote of the episode has to be the following exchange-

I just want to say, you know, you have never been very reliable.
And you have?
You didn't always take me where I wanted to go.
No, but I always took you where you needed to go.
You did!

Of course, we always knew that was how it worked, but now it's been said on screen.

But despite focussing on The Doctor's relationship with his Tardis, the episode didn't neglect Amy and Rory, and showed some real insights into their relationship too. Amy, who's normally full of mad bravado, was allowed to let the mask slip and be vulnerable. The quote "Hold my hand, Rory," when the Tardis took off under House's control was touching, and she was bought face to face with her greatest possible fear - losing Rory not only physically, but emotionally too. Then the real Rory turn up, and show us what she needs him to be - the reliable one, the one sane person in a mad universe. Rory had had a wonderful Genre Savvy moment earlier, when House asked, "Why shouldn't I just kill you now?" and he replied, "Because it wouldn't be any fun." Interesting that the Tardis thought that he was "the pretty one".

This week's cryptic bit - The river is the only water in your forest. River Song, perhaps? she did appear in Forest of the Dead, and also appeared in a forest in Flesh and Stone.

Note to Steven Moffat- ask Neil Gaiman back.