這篇是翻譯自己以前寫了兩篇解釋地磁的來由，首先兩篇都是建基於相對論電磁學的根基，就是當兩個物件中的非自由電子在作相對的旋轉運動時，因為以各自的角度去看，對方的旋轉運動是和自己的旋轉方向相反，所以產生了相斥的電磁場，於是在地球上高速轉動的東西就會因此產生了浮力，此事已被實驗證實。只是因為這些停留在原子軌道電子本身也在做旋轉運動，而不是被完全固定，所以相對旋轉運動就不是工整的圓形，於是這個效應就相對較弱。

把這個原理應用在地球上，我的推想是地球核心有不少流動而含鐵離子的岩漿，一層層地繞箸地心轉動，由於液體黏力(viscosity)的緣故，所以最近地心這一層最快，距離地心愈遠就愈慢，所以每一層以地心為軸作旋轉運動的岩漿於轉動得最遲的地表而言都是向相反的方向作旋轉運動，所以層層累積的效應就形成了地磁南北極。

要驗証這假說，只要量度地球磁場強度是如何隨箸與地心距離愈少而減弱﹐是否合乎岩漿流動的相對速度及含鐵量，理論上當然是愈近地心，地磁愈來愈弱;另一個推論就是地磁應和地球自轉的方向有關，想像一個於真空旋轉的液體行星，要是沒有外來的力距，它的最外層會先向一個方向旋轉，慢慢遲下來再向另一方向旋轉，如此類推，但是由於能量守恆，旋轉的角動量必然愈來愈低，所以過往地球應有無數次地磁逆轉及地磁減弱的記錄，即地表剛誕生時應為最強，之後隨箸岩漿冷卻和凝固，相對旋轉運動愈來愈遲，最後完全凝固時失去地磁。

If we consider that the current theory of the Universe is correct, ie. The Earth is in the Universe and that there are stars and planets which are millions of light years away, then what I cannot get my head around is the notion that the past must not therefore exist.

Because of the incomprehensible distance between us on Earth and other stars and planets in the Solar System, in some cases we are only just receiving the light from some stars that was transmitted in 1066. This got me thinking. Images are essentially light patterns, and whilst the Earth receives light and image, so must it equally transmit light (otherwise we wouldn’t be able to see the Earth from the Moon for example).

So, in this way, if there was to exist some sentient being on a star billions of light years away, they could see the Earth as it was hundreds, thousands of years ago, (the battle of Hastings in 1066 for example could somewhere still exist and be occurring due to the lag in light travel).  Each one of our actions through time are still travelling as light through space, and could be received and seen at any point. Furthermore, if “space” is infinite, every single action on Earth could never be considered a finished action and in the past, as it is floating off through space somewhere, where in maybe one thousand or one billion years it will be picked up on some far away planet.

I don’t actually know the validity of this idea, as I am not a astro-physicist, but on the simplest of levels, I find it a fascinating concept.

My first time seeing a rainbow was a horrible experience.

I was in a beach on a little island with my family. The weather was pretty nice with the sun and a clear sky. Suddenly, there was a shower. Exactly when the shower just stopped, I was chased by a bee. It kept following me on the beach. I ran and screamed. But, of course, someone saved me at the end. At that exact moment, I looked up the sky, there was the rainbow; A rainbow with 4 or 5 colors in the middle of two clouds. That was my first time seeing a real rainbow on the sky. I am amazed by it even it was a very short and thin one.

Ever sine then, I am very curious about what is behind/ under/ at the end of a rainbow. Although I know nothing about it, I still kind of have a thing for rainbow. To me, it represents hope, reborn, blessing and good luck.

I tried to chase a rainbow in a car with my friend. I and my friends made promises under a rainbow. Well, not exactly under it. But, I wish I could someday go underneath a rainbow, a really big and bright one…and make a wish.

OMG…exactly like this one. (photo from wikipedia)

Tif

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Rainbow.

The first thing I think of is the gay right movement.

I never associated gay men with rainbow before. Not before I came to SF and knew about the renowned Castro Street and its rainbow flags.

But I also think of the first rainbow, the rainbow Noah saw when the flood that destroyed almost all life on the earth ended.

And then there is also this physics theory explanation of rainbow. Moisture in the atmosphere after the rain, the sun light, the reflection…Actually, I don’t know much about physics theory.

I remember when I was a kid, I always had this wonder about rainbow. I thought it was mysterious. I firmly believed there must be some power to it. I believed once I got to the end of the rainbow, I could walk on it and it would carry me to the sky.

Later, I learned in school the scientific theory about rainbow, which totally smashed my fantasy about rainbow, but set me for some other fun: my friends and I would try to spray some water under the fierce sun just to produce a rainbow for ourselves.

I like to search for a rainbow after the rain. I love the freshness in the air. It seems it is a new start and everything is going to be great!

LISA

This week marked the 40th anniversary of man landing on the moon. Buzz Aldrin, among others, met with President Obama to discuss plans to create a permanent base on the moon and to one day fly a man to Mars (Aldrin lobbied for bypassing the moon part and going directly to the red planet). One day we will put a man on Mars. And we will probably put a man on its moon, Phobos and Deimos. We may one day put a man on Mercury, but that’s a much more treacherous trip (it’s highly unlikely that we’ll ever put a man on Venus because it’s way too hot; the surface temperature of 480 degrees Celsius can melt lead).

But what then? Maybe we put men on some outer moons, like Europa or Titan. But, after Mars, the excitement of a manned intrasolar trip will be limited. I was asked this week if we’d ever be able to send a man to another solar system. I think answering that question is a good opportunity to learn some interesting physics theory.

Our nearest neighbor star is Alpha Centauri, which his 4.37 light years away. This means, of course, that it takes like 4.37 years to get there. Therefore, if we can send a space ship as fast as fast as possible and get close to the speed of light, it will take the ship 4.37 years to get there, or about 8.8 years for the round trip. That’s not terrible and it’s certainly conceivable that we’d find an astronaut willing to spend about a decade of his life away from our Solar System.

Now, you may say that we don’t have the technology to get a space ship that can move near the speed of light, to which I reply, “rubbish.” There’s no friction in space, so there’s nothing to stop a ship from accelerating forever. A ship with a regular engine and enough fuel to burn can simply turn its engines on and wait until it gets close enough to the speed of light.

There is, however, an interesting complication. As an object moves closer and closer to the speed of light, it becomes harder and harder to accelerate. Meaning, if our ship turns on its engines at a constant burn and leaves them on, it will accelerate at a constant speed AT FIRST, but eventually relativistic effects will come into play, and it will accelerate slower and slower as it gradually approaches the speed of light.

Let’s say that we want to accelerate our ship at 10 m/s/s. I make this choice, of course, because 10 m/s/s is how fast things accelerate in Earth’s gravitational field, so a person in a ship accelerating at that speed would weigh as much as he does on Earth (he would fell gravity due to the accelerating ship, just like you feel a pull forward and backward when your car breaks or accelerates quickly). If you ignore relativity, it will take about HALF a year to reach about HALF speed of light. If you include relativity, it will take approximately the same amount of time. The following graph shows that the change of speed is nearly linear for constant acceleration until you get above about .6 the speed of light:

So, there’s not problem getting fast enough. You have enough fuel to burn for half a year to get up to speed, and then another half a year to slow down. And then you of course need to double that amount if you plan to get back to Earth. So, you need two years worth of fuel, and the rest of the time you simply coast. It would be a lot, but certainly not completely out of the question. (I’m ignoring the change of mass to your ship due to the burning of your fuel. Including that is interesting, but not relevant to this discussion. Just assume that the ship is heavy compared to the mass of the fuel).

But, again, relativity adds an interesting twist. Because the person in the ship is flying at a speed approaching light relative to the Earth, he will experience time differently than his family sitting at home. His will pass through less time than people on Earth and therefore will be younger when he returns to his home planet than people who were his same age when he left. If he moves at half the speed of light, time will pass at ¾ the rate for everybody else as it does for him. So, if someone on Earth ages 10 years, he will only 7.5 years and will be 2.5 years younger than someone who was his same age when he left. So, an astronaut will only have to volunteer to be away from Earth for less than 8 years to complete the journey.

If one wants to do some concrete calculations, one can consider the following scenario. The astronaut blasts off in his ship, accelerates at 10m/s/s half way to the planet (he accelerates the entire time) and then starts to decelerate half way through his journey (so he’ll stop just as he reaches the star). His ship burns fuel with 100% efficiency (meaning you have some sort of nuclear reactor that can convert a mass M of fuel into Mc^2 in energy), and we consider the fact that burning fuel reduces the mass of the ship. This site shows how one can do the relativistic calculations involved and gives some neat results:

Distance                  Location                       Time for astronaut        Fuel
4.3 ly                        nearest star                 3.6 years                             38 kg
27 ly                         Vega                               6.6 years                             886 kg
30,000 ly               Center of  galaxy       20 years                              9.55 * 10^8 kg
2,000,000 ly         Andromeda               28 years                               4.2 *10^12 kg

Finally, this I think is the most interesting part. Consider making a flight to the center of the galaxy. It will take 20 years if you accelerate in the above way, but will cost A LOT of fuel. So, why not just accelerate for about half a year and get very close to the speed of light? Why accelerate the whole way? Since you can’t go faster than light, as you approach the speed of light, accelerating increases your speed by asymptotically smaller and smaller amounts. You end up burning tons and tons of fuel just to increase your speed by, say .2 the speed of light.

So, the actual time for someone on early is nearly unaffected by all this extra effort. However, interestingly, it make a HUGE difference for the person on the ship. If he just accelerated to about half the speed of light and then coasted the rest of the way, it would take the man nearly 60,000 years! However, if he accelerates constantly the whole way, it only takes him 20 years!!! The speeds are very close to each other, but the difference in time is enormous. So, to the astronaut, all that extra fuel spend accelerating the whole way is certainly justified (he can actually live through the trip!!).

Of course, if you’re sending robots who don’t care about the passage of time, you would simply save the money on fuel and only accelerate at the very beginning and the very end. They don’t mind twiddling their thumbs for 60,000 years.

Un objeto real tiene propiedades con valores bien definidos independientemente del orden en que sean medidas. La mecánica cuántica no es una teoría realista. Un sistema cuántico puede presentar propiedades cuyo valor medido depende del orden en el que sean medidas. Lanzas un cubilete con dos dados “cuánticos.” El valor que saldrá en cada dado es diferente si observas ambos dados simultáneamente o uno a uno. Técnicamente, la mecánica cuántica es contextual. El contexto de la medida (cómo se realiza ésta) influye en el resultado obtenido. Así lo han demostrado experimentalmente el sevillano Adán Cabello y sus colaboradores austríacos en el artículo técnico G. Kirchmair et al., “State-independent experimental test of quantum contextuality,” Letter, Nature 460: 494-497, 23 July 2009, como nos cuenta Boris Blinov, “Quantum mechanics: Hidden context,” News and Views, Nature 460: 464-465, 23 July 2009.

Un sevillano publicando en Nature es motivo suficiente para que muchos medios se hayan hecho eco de esta noticia. Por ejemplo, ”Mediciones cuánticas: el sentido común no es suficiente,” Servicio de Información y Noticias Científicas, SINC de la FECYT, 22 julio 2009, “Un equipo internacional de físicos ha realizado en Innsbruck (Austria) un experimento con parejas de iones en el que se muestra que, independientemente del estado en que se preparen los iones, es imposible explicar lo que se observa en términos no contextuales, es decir, suponiendo que los resultados no dependan de otras mediciones compatibles que se hagan sobre el sistema.” Kanijo ha “fusilado” la noticia (no ha tenido ni que molestarse en traducirla). Y cómo no, ha sido meneada. Muchos otros se harán eco de esta noticia y la Francis, cual mula, no puede ser menos.

Kirchmair y sus colaboradores utilizan una técnica de medida sin demolición (QND o quantum non-demolition) que a diferencia de las medidas estándares no provoca el colapso completo (demolición) de la función de onda cuando esta representa estados entrelazados superpuestos. Este proceso es clave en el diseño de ordenadores cuánticos, donde las puertas lógicas cuánticas deben ser capaces de leer el estado de un cubit sin afectar a los demás en un registro de varios cubits. Como el gato de Schrödinger que está simultáneamente vivo y muerto (<vivo>+<muerto>), con dos dados “cuánticos” entrelazados tendríamos 36 posibles estados superpuestos (simultáneos) según la pareja de caras que salga al tirarlos <1,1>+<1,2>+…+<6,6>. Con una medida QND podemos medir uno de los dados sin destruir el estado de superposición obteniendo un nuevo estado <1,k>+<2,k>+…+<6,k>, donde <k> es el estado medido en el primer dado.

Kirchmair y sus colaboradores han estudiado experimentalmente una desigualdad de tipo Bell presentada en 1967 por Kochen y Specker para verificar la no contextualidad de la mecánica cuántica. Ya se demostró una desigualdad más sencilla, de Clauser-Horne-Shimony-Holt, que afirma que <A,B>+<C,D>+<A,C>-<B,D> <= 2, para toda teoría de variables ocultas, desigualdad que se viola desde el punto de vista cuántico, pero que aporta poco sobre el problema de la contextualidad. Kirchmair et al. han considerado estados <v1,v2,v3> donde vi es un valor en A,a,a,B,b,b,C,c, y c, y la desigualdad <A,B,C>+<a,b,c>+<a,b,c>+<A,a,a>+<B,b,b>-<C,c,c> <= 4, para toda teoría de variables ocultas, pero que la mecánica cuántica viola, resultando en un valor mucho mayor (las medidas de un valor de 5.46 +/- 0.03). Este tipo de estados permiten estudiar la contextualidad ya que se puede realizar hasta 3 medidas QND en 6 modos diferentes, que conducen a incumplimientos diferentes de esta desigualdad. Experimentos anteriores ya habían verificado la desigualdad (teorema) de Bell-Kochen-Specker. ¿Qué es lo nuevo? Los investigadores han demostrado que el resultado cuántico es independiente de cómo se preparen inicialmente los estados en superposición (y lo han demostrado con una certeza del 99% utilizando 10 formas diferentes de prepararlos).

Bohr vuelve a vencer a Einstein. Otra demostración más de que no hay ninguna teoría de variables ocultas clásica subyacente a la mecánica cuántica. ¿Qué queda por hacer en el futuro? Habrá que repetir este experimento con un nuevo diseño que permita que los estados en superposición se encuentren separados a una distancia suficientemente grande como para que actúe la no localidad de la mecánica cuántica.

¿Para qué sirve este trabajo de investigación? Su utilidad más directa es en sistemas de cifrado cuántico (basados en el transporte de portadores con tres estados cuánticos) o en las tecnologías de procesamiento de información cuántica que habrá que desarrollar en el camino hacia los futuros ordenadores cuánticos.

One of the fundamental assumptions of modern physics theory is that it works the same everywhere in the Universe. I always wondered why this should be so. I mean, it makes possible a lot of the calculations used in astronomy, but that just makes the assumption convenient -it doesn’t make it necessarily true. I occasionally amuse myself with the game of “what if it were not true.” As such, I’m always on the lookout for stuff which indicates maybe it isn’t true. Here I present two potential pieces of evidence that the assumption about homogeneity of physical law is not true.

The first one is the oldest one, for which there is the most evidence. It is the Pioneer anomaly. Pioneer was a pair of spacecraft that produced the first up close photos and telemetry from Jupiter and Saturn in the early 1970s. They’ve since left the solar system. They are the farthest man-made objects available for study, so people study them very carefully. In fact, they found a very small, but unexplainable anomaly in their motion. It corresponds to an acceleration which is 10^-10m/s^2 towards the sun. Various explanations have been fielded; some pedestrian, some far out -none are particularly satisfying. Pedestrian explanations: perhaps there is lots of dirt slowing them down; perhaps some large mass is out there influencing the things; perhaps the waste heat is large enough to provide this much acceleration. For non-pedestrian explanations, perhaps gravity works differently than we think. This would be a disaster for astronomers and cosmologists. Perhaps physics theory itself is different in different regions of space. Whatever it is, this effect has been pondered for half a decade now, and they haven’t been able to make it go away. I had the germs of a paper trying to tie this to the solar neutrino problem, but I guess I have more self respect than most cosmologists, so I never bothered publishing it.

The latest one is even more disturbing. It indicates that radioactive decay changes over time. In fact, the rate of beta decay of certain nucleotides seems to be strongly correlated with earth’s distance to the sun. Now, in my opinion, this is rather indicative of systematic error -perhaps detector efficiencies are correlated to something that comes from the sun, like heat. They’re postulating something more radical: that neutrino flux (which varies with distance to the sun by 1/R^2) might have an interaction with these isotopes, or even more radical, that the sun emits some previously unknown field that alters the local fine structure constant. The neutrino instance would be a big deal; lots of nuclear models would have to be revisited. A field that alters the fine structure constant would be cataclysmic. They’ve already looked for and not found the effect in the radioactive power plants of the Cassini probe, which to my mind indicated that the effect is likely systematic error. I’m also not encouraged by the fact that the original paper contains statistical measures which look suspiciously like they did their statistics incorrectly. If anyone came to me with 35 data points and claimed correlation with 4×10^-12 probability, I would laugh at them. I’m guessing they got their “formal probability” by cranking it through some Student-T formula, which is pretty much wrong for calculating correlation probabilities like that. In another case, they actually have the kidney to quote a 2^10-246 probability, which is simply absurd. I mean, that sort of number verges on quantum mechanical absurdity (as in, I think it violates the uncertainty principle, though I don’t feel like doing the math). I suspect such primitive statistical ideology may be common in physics theory; physicists never learn real statistics. Financial analysts are arguably a lot more careful with their statistics, and they’re certainly more sophisticated than most physicists are. None the less, the signals are obviously correlated even if the authors arguably didn’t do the calculation right, and it’s an interesting result.

Anyone else read books about quantum physics theory in a bubble bath with a mojito after crazy days, or am I alone in that one?

On that note – what kind of drinks go with what subjects?  I think we need a whole list of drinks here!  Answer any/all in the comments, or suggest your own. 
a.) __________________ is to zoology as mojito is to quantum physics theory.
b.) Tequila is to __________________ as mojito is to quantum physics theory.
c.) __________________ is to forensic anthropology as mojito is to quantum physics theory.
d.) Sake is to __________________ as mojito is to quantum physics theory.

E is for extra credit!
E-1: Mojito (white rum + sugar + lime + sparking water + ice + mint) = quantum physics theory.  Which part(s) represent(s) simply physics theory?
E-2: That taken into account, please explain this version of a chocolate martini:
1 shot chocolate vodka + 2 shots white Godiva chocolate liquor + 1/2 shot creme de cacao + 2 shots whole milk = __________________.

Wait! you say.  Fox the above post has NOTHING to do with physics theory and everything to do with chaos!
To that I can only reply: did you forget who I was? And have you had the pleasure of reading Surely You’re Joking, Mr. Feynman?

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Those meddling mathematicians
continue to blow my mind
I cannot figure it out, perhaps
I am a fraction blind.
Sculpting the fourth dimension
I can see the fatal attraction
as the artist becomes magician
via mathematical abstraction.
The physicists equations
described our physical reality
in only three dimensions
so how can you see
four dimensional objects fly
through time and space?
I am trapped in a hypercube*
in a very dark place.

D.Hinson