You are probably familiar with the following story: 13.8 billion years ago, the Big Bang led to stars and galaxies, which led to planets and life and eventually to you and me. But there is a conspicuous gap in this chronicle, an aperture so great that the solution would shake our knowledge of reality.
“If we in principle pick the best physics theories… we will have to conclude that the universe as we observe it cannot exist,” said Stefan Ulmer, physicist at the RIKEN-led Baryon Antibaryon Symmetry Experiment at the European Council on Nuclear Research .
But … here we play Wordle and pay taxes, so either our physics laws are wrong, or we are missing massive pieces in the metaphysical puzzle.
Among the army of scientists looking for these pieces, Ulmer has spent years studying the germ of our universe’s existential crisis: antibody. In a paper published Wednesday in the journal Nature, he reports an update: Antibody does not respond to gravity differently than normal drug does.
Don’t worry, if the last one flew all over your head, it would all fall apart.
First, what is antibody?
Everything from the sun to the entity you are reading this article about consists of the normal matter we know and love, composed of atoms built with positive protons and negative electrons. The Big Bang gave rise to all this affair, and the rest is literally history.
Here’s the strange part: Our universe also contains a small amount of antibody, composed of atoms built with negative protons and positive electrons. It’s like the Big Bang’s rebel child.
These two also have a rift. When they come in contact, they totally annihilate each other due to their opposite charges. Even when scientists create antibody for experiments, the zipped particles must remain in a vacuum because an antibody particle in a normal substance environment would immediately become “puff”.
This incompatibility dominates down to a huge existential problem – and it’s not just that we can not meet our antibody counterpart one day without basically exploding.
There should have been a particle war
Physicists use two main frameworks to explain particle behavior: the standard model of particle physics and relativistic quantum field theory. Each is super solid in its own right, and combining them leads to a confusing result.
Matter and its arch-enemy are two sides of the same coin.
“The space and time architecture basically implies that matter and antibody are in principle exactly symmetrical,” Ulmer said, “meaning they have the same masses, they have opposite charges, opposite magnetic moments and so on and so forth.”
If true, the Big Bang should have had a 50/50 chance of forming both. And had there been a 50/50 distribution, antibody and substance should have completely destroyed each other. (Do you remember the rift?) With such a particle war, the universe would not have anyone fabric. Space would not accommodate a sun or an earth, and would certainly lack humanity. Only a remnant kind of energy would have lingered after the battle.
But the sun, the earth and humans exist.
For some reason, the universe exhibits several orders of magnitude more matter than antibody, a cosmic riddle known as baryon asymmetry, the namesake of Ulmer’s laboratory. Did Big Bang-generated antibody disappear? Was there never anyone to begin with?
“We do not understand the origin of matter and antibody asymmetry,” Ulmer says simply.
The part where it is connected
Because the Standard Model’s prediction of a 50/50 fabric type distribution depends on the particles being exactly symmetrical, the mystery can finally be solved if we find a way to break the supposed parallel.
“If, let’s say, the proton were a little heavier than the antiproton, that would immediately explain why there is more substance than antibody,” Ulmer said. That would pretty much shed light on why the universe exists.
Let’s return to Ulmer’s study results: Both substance and antibody respond to gravity in the same way and exclude some possibilities in the general ledger of possible symmetry violations.
Ta-da, told you it would collapse.
A proton symphony
Ulmer’s experiment began with a fascinating device called a Penning trap, a small metal device that records the cyclotron frequency of a particle, or the frequency at which something moves in a magnetic field.
The researchers placed a laboratory-produced antiproton inside and measured its cyclotron frequency, after which they popped in a negatively charged brintion and measured the same parameter. (Ulmer used a negatively charged brintion, or atom with a proton and two electrons, as a normal substance because it matched the negative charge of the antiproton).
It’s easiest to think of the experiment in terms of music.
The penning trap’s pickup system, Ulmer says, is akin to what’s in an electric guitar. “It’s a very musical experiment in that sense,” he explained when he was a guitarist himself.
“The frequency range is a little different, but we listen to the sound of what does not exist in the universe,” he added. “With our current ability to listen, [matter and antimatter] sounds identical. “
The particles play the same melody, if you will, which also means that they have the same notes. Alas, the cyclotron frequencies of these particles were the same, as were many of their resulting properties, such as charge-to-mass ratios. All of these similarities have now been eliminated from the list of possible substance-antibody-symmetry violations.
Room as a laboratory
But the researchers’ ultimate goal was to use their cyclotron frequency data and see if the antibody song changes along with adjustments in a gravitational field. Specifically, they tested whether Einstein’s weak principle of equivalence – true for normal matter – acts on antibody.
Einstein’s principle states that every object in a gravitational field behaves independently of its inherent properties. For example, a piano and a feather would fall to Earth with the same acceleration in the absence of external forces such as wind.
Intuitively, we could assume that opposite charges of antibody would force it to “fall up,” or at least have some variation in behavior.
For this facet of the experiment, Ulmer utilized some cosmic laboratory equipment: the Earth and the Sun. “As the Earth orbits the sun in an elliptical orbit,” Ulmer said, “the gravitational potential of our laboratory changes as a function of time.”
So he and his research team measured the cyclotron frequencies, also called the melodies, of both antiproton and negative hydrogen ions at different times. After 24,000 comparisons, they concluded that both particle types reacted equally – with very, very high certainty.
Voila, Einstein’s principle works on antibody. It actually does not fall upwards.
“We will continue to make the microscope better and better to be safe,” Ulmer said, and “if we find anything unexpected in these experiments, this would change our basic understanding of the laws of nature.”
Philosophical consequences of antibody
For the sake of argument, let’s assume that someone finally finds a discrepancy between antibody and substance. What can it mean for us?
Violating drug-antibody symmetry would mean violating a larger phenomenon called CPT invariance. C stands for charge, P for parity and T for time. In a nutshell, the rule says that if any of these things were reversed, the universe would basically remain the same. If time went backwards instead of forwards, if everything was left-handed instead of right-handed, and you guessed it, if all matter had the opposite charge, the world would not change.
If we were to find out that antibody is not the same as normal drug, C would be violated. And if the CPT invariance is violated, causality, scientists say, may no longer hold. “I think this might lead to a more philosophical change in our thinking,” Ulmer said. “Comparable to what happened in the 1920s when quantum mechanics was developed.”
Adds, “up to that point, people thought that everything is deterministic. In quantum theory, things can no longer be deterministic by definition – so this changes how people understand themselves.”
Even more confusing is the realization that because the universe seems to exist, we already know, so to speak, that antibody is up to something. In a way, we already know that we will have to adjust our perspective on reality.
We’re just waiting for the right moment.