At the beginning of everything there was a single dot, infinitely small, infenitely hot, infinitely dense. This singularity, for unknown reasons, started to expend, or better exploded, defining the beginning of everything: space, time, matter and life. The Universe, perfect at birth, should have grown perfect as well, expanding uniformly in all direction. This perfection should have been maintained in time, forcing the particles to keep exactly the same distance between themselves everywhere, all the time and in all directions… Sadly, such a universe wouldn’t have formed any kind of complex particles: neither atoms, stars, galaxy and, for sure, not even life! But hey, look around, we are here! So, what happened to break the primordial equilibrium? Scholars are unclear about this: some says there was a small asymmetry, a very small difference in the amount matter and anti-matter initially formed, and the annihilation just let this little percentage of matter we can admire outthere. Good for us, sorry anti-matter dudes! Ok, but doesn’t it contradict the first statement: perfection? Why would such a perfection have generated more matter then anti-matter?
Let forget for a while this curiousity… In thermodynamics, entropy is a measure of molecular disorder within a macroscopic system, which is commonly interpreted as a measure of disorder present in a physical system whatsoever (yes, including the universe). Entropy never decrease and evolves toward the state with maximum entropy, blablabla… In fact as we said, before the Big Bang, the universe was entirely concentrated in a single point, representing the minimum possible entropy of a system: the perfection. Suddenly the time started, the dot and the entropy of the newly born Universe simultaneously started to grow as well, leading to the actual, incredibly beautiful universe. A beautiful but sad universe made of small particles following the law of thermodynamic is like a giant computer, elaborating the position of atoms and molecules, their speeds and deciding eventually what to do next, when they collide. All of which is potentially predictable… the live of the stars as well the live of any of us, even what we think has been decided from the first instant of life of the universe… or not?
Well, fortunately, there is a branch of physics which may actually defies this hypothesis: quantum mechanics (or the nightmare of Einstein 🙂 ). Many experiments, run on the particles level, has measured that electron, photon, etc appear to behave in very strange ways. For instance, two particles might get entangled (which means that they can be forced to interact in ways such they cannot be described independently: basically, they appears as if they are the same thing in two different places). Whenever this happens, the entropy of the system (the two particles entangled) is no more increasing, it’s completely static. Ahaaa! So we have the proof of an exception to the rule… Are there any other experiments defying the rules? Yes, there are… and they are very very disturbing to… to anyone who tries to understand it!
The double-slit experiment, which demonstrate that light and matter can behave as a waves or a particles based on the environmental condition, was run by “simply” throwing electron through a panel on which we have done two slits. Being fundamentals particles, we’d expect the electrons to go through one or the other slit, such as if we put a wall after the panel, we should see two bands corresponding to the place where the electrons end his flight. This is not what happened: the scientist noticed that the electron formed an interference pattern, just like what we get if waves were going through the panel! But we said that the electrons are particles, not waves, so the scientist decided to check what really happens. And to do so, they put a detector to see from where they were going through. Guess what happened, the pattern disappeared and the two bands showed on the wall. Incredible, the electron was behaving differently if they were observed! This experiment has been repeated many times, with some variants, and the result is always more incredible.
For instance, we could manipulate our experiment so that, after the measurement is done, we “erase” it. How? By setting some device which cancels the first device to detect from which slits the electron actually went through (if you are interested to know how they did it, check for “quantum eraser double slits experiment”). And guess what happens? Yeah! The interference pattern is back!! “But, we measured it!… Yes, but the eraser actually cancelled the validity of the measurement; meaning, it’s like it never happened. Ok, what does that mean? Well, if it was necessary, this proof that the “act” of observing the electron is not influencing its trajectory! It is not “physically” changing something in the electron which change its behavior (or how you would call that particule doing what it does when it’s watched). Thus we cannot say that the wave “collapses” by the act of watching it…
Quantum Zeno effect is another paradox defying the law of entropy. This time we have unstable uranium involved… As we know uranium is unstable and decays over time, so imagine the surprise of Texas scientists when, after a day spent observing some unstable uranium, they just see it was not really doing anything. So, they left it alone and it did decay as expected… They spent another day observing it and again the uranium stopped doing anything! Uranium will never decay if you’re observing it… Are we stopping time or is the uranium just kidding with the scientist?
Quantum tunneling… oh, yeah, we could talk about this one too, particles going through the walls like Harry Potter.
Interpretation? Well, there is the Copenhagen interpretation, whereas it is said that physical systems do not have definite properties prior to being measured, so that we can only predict the probabilities that measurements will produce certain results. Basically the act of measurement affects the system, causing the set of probabilities to reduce to only one of the possible values immediately after the measurement. This feature is known as wavefunction collapse which, as I wrote earlier appears to be contradicted by the “quantum eraser” version of the double split experiment (at least this is what I understood of it 🙂 ).
Then, there is the many-worlds interpretation which requires that all possible alternate outcomes and futures are real, each happening in an actual “world” (or “universe”), having other me (and you) observing. I really don’t like this interpretation, personally as it requires an infinite number of Universe, which is simply mathematically impossible. “Infinity” is a nice concept but it really cannot bind with reality: imagine to put all those universes inline, an infinite line (right?) starting on one side by “our” Universe. Now try watching as far as you can to the right, to see the last Universe. See it? 🙂 Ok, now I will compact all the line of universes so that it fits a segment I can easily see entirely. Which side of this segment would be the Universe you been selecting before? Left, somewhere in the middle or to the right? To the extreme left!! As if you would have actually been putting you eyes on the Universe 1… that simply cannot be…
There are few other interpretation but the Copenhagen and many-worlds interpretation basically cover all because the first one is like an exclusive “or” (this reality or that one exists), while the second is like an “and” (this reality and that one exists always in multiple worlds). If we reject both, what can it be? Einstein suggested that there is actually no “superposition” of the states, simply we do not know how measure it effectively, as there may be some “hidden-variable”. Which has been rejected as it requires information travelling faster than speed of light but still…
Conclusion/question: quantum effects shows beyond any doubt that “observing” the particules affects their intrinsic nature or their behavior in our world. Considering that the universe was born the size of the Planck constant (even way way way smaller than an atom), we might safely deduce it certainly started obeying to quantum mechanics right? Now, respectable scientist will never ever asks such questions… but I’m not a scientist so…… shouldn’t this quantum universe have expanded forever as an undisturbed waves, if there wasn’t any observer out there? What caused it to “collapse”? Or maybe… who???
Counting To God: A Personal Journey Through Science to Belief (English Edition)