If you still watch TV news after that...

Sinking deeper than the bottom of the ocean: ABCYou have heard about "Botox Mom", haven't you? This charming lady claimed on TV that she was giving her 8-year old daughter Botox shots in order to remove imaginary wrinkles and prepare her for some of those horrible "beauty" pageants.

Of course, Child Protection Services promptly investigated and removed the child from her custody as a precautionary measure.

Well, what do you know? The latest development in the affair is that the mom apparently had made it all up, and had been paid for it by the TV networks that aired her story.

That makes her a slightly less horrible parent, as she is only just lying and pushing her daughter to lie on TV and profiting from said lies.

But what I take from it is that it's now official: in case you hadn't noticed, those TV things now have nothing whatsoever to do with news. They really are pure (and lousy) fiction, and as such are performed by actors who are paid to tell a pre-written story.

In other news... http://www.slate.com/id/2291942/entry/2293553/?from=rss

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More Aperture Science: the Light Bridge

The Light BridgePortals are not Aperture Science's only remarkable scientific accomplishment. Among their other inventions is the Light Bridge, that provides a stable and seemingly immaterial surface that people can stand on. The bridge can also be turned on or off instantly.

How does it work and is it really made of light?

It certainly emits light but it most definitely isn't made of it. For light to be able to withstand the weight of a person would require an amount of energy that would have to be directed upwards and that would be sufficient to fry them instantly.

There is little information available on Light Bridges but similar technology has been mastered by others. One declaration we were able to get from an Aperture representative is the following:

"If you rub your cheek on it, it feels just like being outside, with the sun shining on your face. It will also set your hair on fire, so don't actually do it."

This is because the bridge seems to be a stationary wave of photinos, the supersymmetric partners of photons. Around the surface of the bridge, there is an evanescent wave that is characteristic of a phenomenon of total reflection.

The tricky part is that what is being totally reflected on the surface is the quantum wave function of all fermions above the bridge. In other words, the force exerted by the bridge on what stands on it is purely quantum mechanical in nature, similar to what keeps electrons in separate atomic orbitals or to what keeps a neutron star from collapsing further. It could even be seen as a sort of reverse-quantum-tunneling effect, where objects cannot possibly move any farther. An anti-portal of sorts.

Now light can still pass through because it's made of bosons, of course, which explains the translucency. The blue color is due to the disintegration of some of the photinos that form the bridge.

There is a cylindrical version of the light bridge that is used as a tractor beam and that is obtained by not making the photino wave exactly stationary.

That is it for today. I'll take questions now.

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The physics of portals

Fuckin' portals - how do they work?You heard it like me, someone just asked about the physics of Aperture Science's neat Portal Gun. I'll try to give an account of what we know from the material that Aperture recently made available and from what can be deduced from demonstrations of the product.

Unfortunately I've been unable to get any additional information or confirmation of my findings from Aperture themselves as the only person I was able to contact, a Mrs. Glados, told me on the phone that "all the persons who are still alive are currently unavailable, but as you seem to have an interest in doing science, I'd be happy to show you around our test chambers. We are open 24/7. I hope you like orange. Can you bring some cake? I don't want to lie to you: we seem to have run out."

So let's get going, shall we? Here's how the gun works:

The Portal Gun (source Aperture Science)

The central part of the Portal Gun is a miniature black hole with a Schwarzschild diameter of a few centimeters. Now black holes this size usually radiate strong amounts of Hawking radiation, resulting in their rapid evaporation. This is counterbalanced by an extraordinarily simple device, in the form of a cooling fan that blows evaporated virtual particles back onto the black hole's horizon.

Above and below the black hole, there are two ring singularity rings that can be made to rotate one way or another in order to communicate angular momentum to the black hole (this is why operating the gun while moving creates the impression that it is being gently pulled out of your hands, by gyroscopic effect). Making the hole rotate results in the event horizon opening up and revealing the ring singularity inside.

The fan is then sped up suddenly behind the singularity to blow part of it forward into the portal intake manifold, focused by the three quantum shaping prongs that you can see moving around the front end of the gun when firing a portal. The focalization is necessary but not sufficient, as the singularity needs to be stopped by a surface charged with Z bosons. This is why Aperture is building special panels for their test chambers, the only surfaces that can stop portals in place. Whenever you attempt to fire a portal on a different surface, the portal continues its course through space unaffected while the dye is stopped by the wall and produces a spray of color at the impact point. This of course makes portal guns unusable in practice outside of a specially equipped test facility.

It's worth mentioning at this point that it is a trivial cosmetic detail that orange or blue dye is injected around the singularity at the precise moment when it passes through the intake manifold. The dye then enters into the gravitational orbit of the ring singularity and remains there as long as the portal remains active, creating the rotating colored shimmer that we all know and love.

Now here is the tricky part: when you fire the second half of the portal, it is emitted as a second ring singularity that rotates counter to the orientation of the first one and most importantly while being entangled with it. It is this quantum gravitational entanglement that does the job of bridging space-time on both sides of the portal. Contrary to common belief, Aperture's portals work by creating a quantum tunneling channel between two locations and not at all by creating a wormhole. Creating wormholes requires considerably more energy, making the process unsuitable to the construction of portable devices. Furthermore, as Black Mesa recently showed, we do not know how to control which universe the other end of the wormhole comes from.

It is often asked whether portals are limited to connecting points in space or if they could permit time travel like wormholes do. Well, if you can find a way to aim in the direction of the past or future, which are unfortunately orthogonal to the three dimensions of space that we are familiar with, then yes, it is possible. Good luck with that.

Now that we understand how the gun works, we can look at the energetic consequences of punching tunnels into space. One thing that all people who have operated a portal gun report is that if they create a portal between two places that present a potential gravitational energy gradient (in layman terms, different altitudes), there is wind coming out of the top portal and entering the bottom portal. This wind gets stronger with the altitude difference.

This is very easy to understand as the difference in potential energy between the two ends of the portal manifests itself like any potential energy gradient: by a force from highest to lowest potential.

That leads us to an interesting point which is that air is affected by portals in exactly the same way that we or any massive object such as a weighted cube is. If for example you punch vertically aligned portals on the floor and ceiling of a test chamber, the air in the room will start falling through, creating a strong wind that will blow downwards, attracting passers by in virtue of the Venturi effect.

Another amusing consequence is that falling through such a portal pair, you can reach speeds much higher than the normal terminal velocity in the same conditions of pressure and temperature.

A gravitational turbine, as used by Aperture ScienceThis effect is actually used by Aperture Science to produce the considerable energy that their testing facility consumes: weighed cubes are left to fall between two portals in a tall well, and a turbine harvests the gravitational energy transformed into kinetic energy along the way.

Now of course the next question is where does this energy come from? Well, the portal itself carries little energy and it doesn't seem to decay as energy is harvested. Many speculations have been made about this but the most plausible explanation seems to be as follows.

Conservation of energy, as everyone knows, is not a principle in itself but rather is a consequence of the laws of physics being the same at all points in time. Ergo, all you have to do is to break the laws of physics in order for energy to stop being conserved. And you'll have to admit that a persisting quantum tunneling device is as weird as it gets.

The effect of this is that constants such as the fine structure constant or the gravitational constant are probably varying slightly as more stuff gets dumped into portals, possibly resulting eventually in atoms failing to retain electrons, galaxies to dissolve or the Sun to transform into a black hole. But don't worry too much, that should take at least a few centuries to happen if my calculations are right.

Well, this is it in a nutshell. I'm going to take questions now.

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Rees, ethics, aesthetics and religion

Sir Martin Rees said this right after receiving a huge pile of money from the Templeton Foundation:

[…]I think just as religion is separate from science, so is ethics separate from science. So is aesthetics separate from science. And so are many other things. There are lots of important things that are separate from science.

"Just as"? When is the last time you heard a philosopher of ethics or aesthetics make a claim about the origin of life or of the universe? Or, for that matter, make any claim that directly contradicted hard science?

This insistence that religion and science are non-overlapping magisteria is decidedly strange. Science's magisterium is very clearly defined: it's everything that is a natural phenomenon. If religions want to stop overlapping with that, it's fine by me but are they prepared to do that?

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About nuclear energy

Credit: U.S. Nuclear Regulatory CommissionI just read Brian Dunning's post about the Fukushima explosion and was about to comment there but they are blocking comments from behind proxies, which is incredibly stupid on their part. So there, new post.

Dunning is a strong supporter of nuclear energy, which is fine. I used to be fiercely in that camp until fairly recently, based on scientific facts about our current technical ability to build secure plants and about the danger that other traditional energies present in a much more real way (look up the death toll for coal to see what I mean).

What made me change my mind is the realization that nuclear energy is surrounded by an opaque cloud of secret, all over the world. This is essentially a world where no transparency exists at all. We know very well what happens when there is no transparency: people cut corners and get away with it. In the case of nuclear energy, cutting corners is particularly tragic.

Another reason to be rationally against nuclear energy today of course is also that we should focus our efforts instead on making renewable energies viable.

Dunning, in his post, argues that coal is much more dangerous than nuclear energy. That's a feeble argument: we should also get rid of coal, starting now. One does not preclude the other, we can do both.

The Fukushima accident, even though not the final proof of the horribleness of nuclear energy in principle, should give us pause, and stimulate debate. What is the state of currently running plants? What should we replace them with at the end of their lifetimes? Did we tragically underestimate natural catastrophe risks for some of those plants? And also, very importantly, how do we reach transparency on nuclear energy and waste disposal? Those, I think, are questions worth asking.

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Do not reward luck

Dead monkeyHere is a little experiment. I have built a bunch of programmed agents that are using a variety of strategies to try and predict the outcome of a randomized event. The event in question is the roll of a dice. The twist is that the probabilities of all sides of the dice are not equal: there is a distribution of probabilities that is itself decided randomly before the experiment.

Here is a table showing how well each of the agents did on a hundred throws of that unfair dice:

  • Agent 1: 18
  • Agent 2: 22
  • Agent 3: 20
  • Agent 4: 10
  • Agent 5: 14

Assuming you can't make any further tests, which agent would you hire to predict future throws?

The correct answer is none of them: you just don't have enough data. So let's throw the dice an additional thousand times:

  • Agent 1: 180
  • Agent 2: 188
  • Agent 3: 176
  • Agent 4: 136
  • Agent 5: 168

What can we notice here? Agent 2 still seems to be doing pretty well, and agent 4 is still doing poorly, might you say. Well, that's true but irrelevant.

What you should be noticing is that the average probability of a hit over all the agents and over all the throws we've made is 0.169. But wait a minute. The probability of a completely random number between 1 and 6 is 0.167. That's pretty close. Just way too close to be a coincidence, as additional data would confirm.

You should by now have understood that I lied: that dice is not weighed at all, the numbers are as close to random as I know how to make (I used crypto-random numbers).

Our five agents do have various strategies (ranging from always picking the same number to picking the number that came out most often in the past) but the point is that it doesn't matter. There is no way to predict a random phenomenon (otherwise it's not random). No strategy works. None ever will. They are all equivalent to chance.

Now what am I getting at? The main lessons we can extract from this are the following:

  1. You can usually determine with a good level of certainty whether a phenomenon is random by confronting its statistics with something you know to be random (it's sometimes trickier than that but is mostly reliable).
  2. Luck in the past is not an indicator of luck in the future. Do not reward it.
  3. In order to distinguish luck from talent, you need to determine first whether the domain where they apply is predictable and only once that's been shown, to consider previous results of the candidate.

To conclude, I'll leave you with this thought. What profession rewards its members with extravagant bonuses whereas it's been shown that dart-throwing monkeys were consistently doing better than any of them in the long run?

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Apologetics is not a proper form of reasoning

Apologetics is the systematic defense of a position. It's usually done by religious people in defense of their dogma.

We are all biased, but embracing bias as the starting point of your reasoning is not going to help you find any reliable truth.

Contrast that with scientifically obtained information. All scientists have their own bias, but scientific methods are designed to eliminate that bias. That's what they do: neutralize subjectivity. Imperfectly, but better than anything else we know. As a consequence, they are our best chance to discover objective truth.

When a new idea emerges in science, the very first thing scientists do is attempt to destroy it. That is not in defense of any kind of orthodoxy, it's to verify that the idea really is a good.

Can apologists reach any form of truth? They could, by chance, but even if they did, what they find would be of no value until it's been scrutinized and verified by a wide community of independent researchers. Why not start with that? Are you interested in finding the truth or in defending your position?

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The Unicorn Paradox

Dieu Et Mon DroitThe other day I heard someone say this on NPR:

You can only see unicorns if you truly believe in them.

That made me think: what can you tell that person that would possibly convince her that unicorns don't really exist? If nobody sees them, it's not that they don't exist, it's just that people don't have enough faith!

Here you have an assertion that is obviously not rooted in anything real, but still there is no way you can really refute it. It's somehow reminiscent of the Invisible Pink Unicorn or the Dragon in the Garage.

What do you think? Do you have your own unicorns? How do you react when faced with this kind of rhetoric?

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“One cannot prove a universal negative” Oh really?

The Mad Hatter stuffing a teapotThis is a claim I've read so many times in comments that I think it deserves a little debunking. If you do a search on that little sentence, you'll see that it's very rarely if ever used in a scientific context but is repeated like a mantra by religious apologists. They seem to be persuaded that it is an established rule of logic.

Let's get it out of the way: it isn't. Here is a counter-example:

No even number that is larger than two is prime.

Done. I hope you'll agree that the proof to this is trivial.

One can prove a universal negative. Declaring otherwise pretty much constitutes a logical fallacy in itself. A universal negative poses no logical challenge whatsoever.

Now this of course applies to mathematics. When it comes to empirical truth, the challenge is quite different: one doesn't deal with proof whatsoever. Instead, you deal with evidence, no amount of which is ever equivalent to proof. Some assertions can be backed with more or less lines of evidence of various quality, which does make some assertions more valuable than others. But proof? Nope. Never. No big deal, too.

Apologists who resort to this false argument might as well say that science cannot prove anything. No it can't. Nor does it ever claim to.

But the absence of proof for not A does not mean that A, let alone B is true. The absence of proof for the non-existence of God does not mean that the Abrahamic God, or Zeus, or the Flying Spaghetti Monster exists. The absence of proof for the absence of a teapot orbiting the Sun between the Earth and Mars does not mean that there is a red teapot there.

Believe what you will. But if you are going to argue for your belief in scientific-sounding terms, or if you make claims that overlap with science (which all religions do), be prepared, and avoid making stuff up. Oh wait...

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The fact checking generation

RotativeI'm not very good at predicting the future (because I'm just one individual out of several billion) but I'll give it a shot today, and try to make it some sort of message of hope.

The greatest revolutions in the history of Mankind, the ones that moved humanity forward in a measurable and long-term fashion, such as the invention of the movable type, owe their success to the way they made knowledge more easily available to more people.

We are in the middle of such a revolution.

The generation of my children is the first one in the history of Mankind for which information will be ambient, and where the entirety of human knowledge will be available all the time to everyone and everywhere.

This fact gives them an amazing power: whenever an extraordinary claim will be made, someone will go "ORLY? Let me check that (LOL)… Oh look, that's actually BS." Or, even better: "that's an interesting idea. Did really nobody come up with that before? Let me check it out… Wow, you really are up to something here. Let's see how far we can push it."

Seriously, gullibility should have no excuse with this generation and I'm convinced that should make it the most successful in the history of Mankind.

Here's to hope on this Christmas 2010.

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