Our universe contains many mysteries, but few people stop to think about numbers that appear almost everywhere. Some irrational numbers, such as PIS, are present in many places. But if you ask some physicists which is the most mysterious number they know, several of them will tell you a number that you've probably never heard of.
1 on 137. To be more precise, we could say 1 over 137. 03599 or even 0.
0072973. But for the sake of practicality, in this video we'll refer to this number simply as 1 over 137. At first glance it appears to be just a random fraction that you could find by solving math, but nothing too unusual.
If you had to choose a number that you find most mysterious, I very much doubt that you would would choose 1 over 137. But if you show that same number to a theoretical physicist, the reaction will be completely different. The physicist Richard Feynman, very famous, once described it as one of the greatest mysteries of physics, a magic number that comes to us without any understanding by man.
Feynman also said that every good theoretical physicist had this number on a wall and worried about it. Nobel Prize-winning physicist Wolfgang Pauli, said that the first question he would ask the devil when he died would be what it meant to him. of that number.
Pauli spent part of his life trying to decipher what this number meant. Somehow, it seemed that the universe itself had given it to us as a gift. He died of cancer in on December 15, 1958, after falling ill during a lecture a few weeks earlier.
And guess what, the number of the last hospital room he stayed in was room number 1 over 137. Friends, family and visitors who went to see them a few days before he died said that Pauli talked about the fact that he was in room number 137 and for everyone to come and see him. But what is so special about the number 1 over 137 that it made one of the greatest physicists of the 20th century, also one of the fathers of quantum mechanics, to stay focused on it until the day he died?
This number has a name, fine structure constant, and in physics it is represented by the letter Greek alpha. In equation form, the number is represented as the square of the electron's charge over 4 pi times the permittivity of the vacuum times the reduced Planck constant times the speed of light. That's quite a lot.
If you look closely at this equation, you'll realize that it's composed of by constants such as the speed of light. And constants are things we're already used to within physics, we see constants all the time. The speed constant itself of light appears directly in equations from quantum mechanics to general relativity.
The gravitational constant is perhaps one of the most important constants along with that of light. Even Planck's constant appears in a series of equations and is almost a pilada quantum mechanics. But none of them is called the mysterious number of the universe, and few have left so many physicists obsessed for much of their lives.
And to understand what took sleep of so many theoretical physicists, we need to go back in time to the birth of mechanics quantum mechanics. Quantum mechanics began to advance at the end of the 19th century and the beginning of the 20th century, when physicists began to wonder what matter was made of. Various physicists have carried out various experiments and proposed different models to understand what matter.
And one of the fundamental experiments to understand what the atom is like was the emission of lines, mainly from hydrogen. When an electron receives energy, it jumps from one lower energy level to a higher energy level. But nature will always seek the degree of lowest possible energy, so the electron goes back to the lowest energy level e, in this process, it needs to release energy.
The way the electron releases energy is through photons, that is, by emitting light, which are electromagnetic waves. And depending on the energy level, the electron emits photons with a given energy or a given wavelength related to that energy. We observe this emission through the emission lines, and those of hydrogen are special because they are found in the visible spectrum.
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br and dress the universe together with me, because every T-shirt of my brand has a profound meaning. Now back to the video. Over time, the experiment became more and more more sensitive, and so the results started to become more sensitive and something strange started to happen.
to appear. Where the emission lines were, experimental physicists began to find no just one line, but two lines very, very, very close together. So close that without the right equipment they appear to be just one.
And it wasn't until 1916 that physicist Arnold Sommerfeld was able to explain the reason for these two lines. Sommerfeld realized that each level of energy level depended on the spins of each electron, so it was as if there were two levels of extremely close to each other. And the separation between these two energy levels has been given the name fine structure.
Sommerfeld also realized that the distance was always a multiple of a certain number, or rather of a certain equation. This equation results in 7. 297352.
5693 times to the power of 10 to the minus 3, or rounding in fraction form 1 over 137. But what exactly was the reason for a separation of the atom's energy level cause so much interest among physicists? They didn't have things more interesting things in the universe to research, like black holes in dark matter?
And this is where I ask for calm. I only spoke of where the mysterious 1 over 137 appears. And right here we can already see it a strange thing looking at the equation.
If you open each unit and each constant, you'll notice that all the units cancel each other out leaving a dimensionless number. In other words, the constant of fine structure is dimensionless, regardless of which units of measurement you use. Numbers are not uncommon, but they are curious for the following reason.
A civilization would arrive at the same number without needing to know the definition of meters, seconds or any other unit. This number is universal in the sense that it is not exclusive to only to the units that we human beings create. But the number 1 over 137 began to attract attention not because it was dimensionless and a good way to communicate with aliens, but because it started appearing literally all the time.
If you take Bohr's atomic model, which today is a outdated model, but interesting from a physical point of view, the speed that an electron would have when orbiting the nucleus with the lowest energy level, divided by the speed of light, would be 1 over 137. Or if you were to compare the energy of this electron with the rest energy, you arrive at the number 1 over 137 squared. Departing from Bohr's model, supposing you take two electrons and put them at one certain distance, in order to overcome the electrical repulsion between the two, you'll need an amount of energy.
Now take this energy and divide it by the energy of a photon with the length the size of that distance, 1 over 137. And if you go even deeper, you'll find this number more often. If you take the circumference of a circle and divide by twice the radius of that circle, you will find pi.
Sorry, it was just a joke. The fine structure constant always comes up when you analyze the relationship between charged particles and the electromagnetic field. Basically, the constant seems to be telling us something, but we have no idea what.
We always observe the fine structure constant when the electromagnetic force is in some sort of relationship with charges. And here is a perfect place to bring the concept of coupling, which means the interaction of two things, like atoms. When two particles are approaching each other, there is an probability that they will interact, that is, that they will collide.
Physicist Richard Feynman was the responsible for introducing something called Feynman diagrams, which make it easier to visualize these interactions between particles. And in these diagrams, we can see whether two particles can interact or not, and calculate the probability of interaction between them. The structure constant when squared, arises with a probability that an electron tends to absorb or emit a photon.
So here we can say that the constant is like a kind of coupling force of the electromagnetic force, or in an easier way, it's the force of the relationship between electric charges and the electromagnetic field. So this way we can understand it better why the examples I gave arrived at this constant. What remains strange is the following, why is it dimensionless and why does it have the value it has?
The gravitational constant can be seen as a way of measuring the force with which two particles are interacting, and it has units of meter cubed divided by kilogram times second squared. I can change these units if I want, I can say that one meter is the size of my dog, Plank, and that one second is the exact length of this video. If I make these changes I will arrive at a new value for the gravitational constant, which will agree with these new units I've just invented.
But this doesn't happen with the fine structure constant, it's as if the number on its own is important, it seems to be saying something that we haven't managed to grasp yet. And the number is constant in the sense that it is the same, no matter where in the universe we measure it, nor at what time in the universe we measure it. universe, but it depends on energy.
The value of this constant changes according to the energy of the system that we observe changes, and this is quite curious, especially considering that during the first moments of the universe, just after the Big Bang, the energy density was extremely high. high, and under these conditions we expect the value of this constant to be close to 1. But as the universe expanded in the following moments, the number decreased until it reached the value of 1 about 137.
But why? What made this number park here? Why don't we see number change when we observe stars and galaxies in the early universe?
What prevents it from arriving to zero, or at least closer to zero? Not that I'm complaining too much because our very existence is linked to this number and its exact value. If the value were lower than this, the electrons would be interacting too weakly with the charge in the atoms.
This means that the atoms would be very unstable and it would be difficult to maintain an atom in the form we know. Some theoretical calculations show that if the value of this constant were only 4% smaller than the current value, it would be impossible to form the element carbon. And carbon is essential for life as we know it.
Without it, we wouldn't have elements heavier. Besides, if stars couldn't form carbon, they would die well and form only the first elements of the periodic table. On the other hand, if the constant were a little higher than the value it has, the electrons would be trapped much more strongly to the nucleus of atoms.
And that would make it difficult for electrons and the atoms themselves to make bonds to form molecules or chemical reactions. It's as if the universe had chosen the exact value of this constant by hand, and we don't know how it came about. Some physicists suggest that the constant is an important ingredient in the search for a unified theory of physics.
The fact that she is dimensionless and appears in various situations, would mean that she could be a way of relating different areas in physics. And others even suggest that all the constants, such as gravitational or the speed of light, are related to this constant, and that it defines all the values we see today. And there are also those who believe that this number is giving us some information about the formation of matter itself, ie, of what matter is made.
Basically, the universe has given us a riddle and we have to guess to find the answer we want. But there are also people who suggest that this number is not special, and it works exactly like pi works, which is also a dimensionless number and appears in almost everything in physics. Pi is a mathematical constant, and there are suggestions that alpha is also a mathematical constant.
We just don't know exactly where it came from yet. Anyway, this is one of the mysteries in physics that has lasted for over 100 years, and famous physicists who defined quantum mechanics died curious about it. But what about you?
What do you think? Could this number be giving us the answer to all the mysteries of the universe, or is it just our obsession with searching for patterns? I would like to know what you think here in the comments.
Thank you very much and see you next time! Blackbird singing in the dead of night, take these broken wings and learn to fly.
