In a laboratory in Paris, the French physicist determined very precisely the value of the number that makes up the universe. The analogy offers new insight into the question of whether the unknown remain hidden in the nooks and crannies of reality.
No, not “42”. With this strange answer, the supercomputer Deep Thought enters a popular scene from classic science fiction movies The Hitchhiker’s Guide to the Galaxy When asked about “the answer to the question about life, the universe and everything.”
However it could have been done. Because although the so-called microstructure constant is a little less comprehensive than “this one question,” it is not that important either.
“A universe in which this constant has a different value may look completely different,” says physicist Saida Qailati-Khalifa, the lead author of the book. An article in a trade magazine nature She and her colleagues provide the most accurate value of the stationary world popular among physicists.
Food for the number of pagans
In her laboratory at the Pierre-Marie Curie University in Paris, she precisely determined 9 decimal places that α, as physicists call it constant in their formulas, has a value – respiration – of one divided by 137.035999206.
Food for a number of fondness, but not closely related otherwise? Well, α plays a very big role in modern physics for that. For example, the constant determines how light moves through a room and how strong the electromagnetic force is, the force with which a magnet attaches to a refrigerator door.
Since α is so small this force is relatively weak. This means, among other things, that electrons (negatively charged) that dance like clouds around the nuclei of atoms (positively charged) do not collapse in a thunderous blow. Something that would cause matter to collapse in everything from our bodies to nebulae and stars in the depths of the universe.
“The microstructure constant is everywhere in physics,” says Qalati Khalifa. Thus, accurately determining the value also serves as a stress test for many of our natural laws.
However, the microstructure constant is only one of several basic natural constants known to physicists. “The total is probably 26,” says Pete Mulders, affiliated with the Nikhef National Physics Institute. Together they define what the Standard Model of particle physics looks like, and the model that captures all known particles (the smallest building blocks of everything around us) and their mutual interactions in one comprehensive mathematical description. “The known masses of particles, the strength of the Higgs field, the energy in empty space – these are all values that the universe has placed for us,” he says.
Physicists do not understand why these numbers have such value. But if they were a little different, the reality around us would cease with the creak of my existence. Turn the wrong knobs and you can make the gravity too weak, for example That the galaxies separate themselves from each other, the Earth is separating itself from the sun – and if we’re really unlucky – people are thrown out of the Earth like drops of water from the spindle of power.
Guellati-Khelifa also thinks important, all these are constants. However, the microstructure constant is most specific to it. A lot of constants Express yourself in units, she says. For example, you could write the mass of the proton in kilograms (1672.623.1 x 10−27 kg), but also in so-called electron volts (938 MeV / c2), such as More common in particle physics. This actually means exactly the same thing, but the number you type in is suddenly different. “This does not apply to α and a number of other constants,” says Qalati Khalifa. It is dimensionless and therefore eternal. Always the same everywhere. And this is wonderful for a number of romantics.
A lot of patience
For 22 years, Guellati-Khelifa has been busy defining the constant more accurately. “Of course this does not mean that I have also been measuring for 22 years, but it does mean that I have made increasingly precise instruments, developed better experimental techniques and gradually learned to understand the physical phenomena that underlie our experience,” she says. … with the new design – three times more accurate than the measurement made by US competitors In 2018 – As temporary lighting.
Mulders describes the result with admiration. You must be very patient with this measurement. And this while you know that you can expect a lot of criticism if even one detail in the implementation is wrong.
rotation from Earth
The experiment by Guellati-Khélifa and colleagues maps the microstructure constant by measuring the effect that the rubidium atom receives when it absorbs a photon, a light particle. With some calculations, you can translate the power of that hit into α.
This is such a delicate task that the researchers provide an error table in their paper that takes into account everything from the influence of gravity to the small effect on the experience of rotating the Earth on its axis.
At the bottom of the line, all this work by Monk Gilati Khalifa and his colleagues provides not only a new record, but also a fresh look at the smallest details of our natural laws. For example, the microstructure constant says something about the existence of particles that could be the cause of dark matter – a mysterious “matter” found in great numbers in the universe that physicists have so far only seen indirectly, through their influence. gravity.
For now, the measurement still strictly follows the predictions of the Standard Model. If in reality unknown objects are hiding in the smallest nooks and crannies, her experience has yet to reveal them. “But if we come to a more precise definition later, we might still be able to get a glimpse of new physics,” she says firmly. Even after 22 years Her quest for the ultimate measure of the magic number upon which our reality depends is far from over.