The Anti-Universe
Universe running backwards in time
Quantum mechanics doesn’t predict a single solid result when undergoing an observation. On the contrary, it predicts a number of different possible outcomes. Similarly, entropy is a measure of the number of possible arrangements the atoms in a system can have. And when trying to take both these into consideration, we land in the world of multiple possibilities — one of them being Anti-Universe.
It was Paul Dirac who predicted that the electron has a partner — an antielectron or simply, a positron. Carl D. Anderson while analyzing cosmic rays, discovered the positron.
- 1932 — positrons or anti-electrons were discovered.
- 1955 — anti-protons discovered.
- 1995 — Scientists at CERN discovered even anti-atoms — these are the anti-matter counterpart of an atom. They don’t last much longer. These survived just for 40- billionths of a second before coming into contact with ordinary matter and annihilating.
Anderson noticed the following properties of the newly discovered positron:
- The mass equals the mass of the electron.
- The charge has the same magnitude as the electron’s charge but is positive instead of negative.
- The particle is always created in pairs with electrons.
- When this particle collides with an electron, both annihilate.
So, in a nutshell, the discovery of positron proved Dirac’s theory right. We know that every particle has an exact antiparticle too, with which it would finally annihilate. It is now known that all the so-called elementary particles have antimatter counterparts. As per, E=mc², the collision between positron and electron, transforms their masses into energy. Matter and antimatter cannot coexist at close range for more than a small fraction of a second, so when coming into contact they collide and annihilate each other — giving off large amounts of energy in the form of gamma rays or elementary particles.
The concept is beautifully stated in Stephen Hawking’s, Our Brief History Of Time, where he says, “There could be whole antiworlds and antipeople made up of antiparticles. If you meet your antiself, don’t shake hands! You would both vanish in a great flash of light.”
It is evident that our universe barely contains any anti matter but we know( theoritically) that during the big bang matter formation had to be accompanied by anti-matter formation. (Also the reverse process is possible i.e when matter and anti matter annihilate energy is produced) .
So there might arise a question in the back of your mind saying, ‘if matter and antimatter annihilate each other, then where does the present matter in the universe come from?’
The answer to this question is equally interesting. Scientists say that most of the particles created in the early universe were annihilated by anti-particles. But, some of these (one in a billion) particles had no matching anti-particles. So these particles survived to form the matter we observe in the present moment today, inside stars and galaxies.
Even Schrödinger’s cat and quantum decoherence states that two state continue to exist separate and decoherent from each other, creating a new branch of reality based upon the two outcomes. So quantum decoherence ensures that different outcomes have no interaction with each other. Even when we look into the multiverse theory, there is a type of universe that flows backwards in time. To know more about multiverse, click the link embedded below.
CPT symmetry
It’s the most important part of this article as the genesis of anti-universe theory has basis in it. We know our all the laws of physics took birth in symmetries. Physics has identified a set of fundamental symmetries in nature. Some scientists believe the symmetry properties exist in our physical reality because our physical reality is a mathematical structure.
CPT symmetry has been recognized as the fundamental property of physical laws. There are three factors understood to be symmetrical throughout the universe — The three most important symmetries are: charge (if you flip the charges of all the particles involved in interaction to their opposite charge, you’ll get the same interaction); parity (if you look at the mirror image of interaction, you get the same result); and time (if you run an interaction backward in time, it looks the same).
At the particle level, the universe appears CPT symmetric. The general notion is that a physical system(made up of particles) will follow the same laws as an identical system made up of anti-particles like a mirror image of one another. To preserve the CPT symmetry throughout the cosmos, there must be a mirror-image cosmos that just balances out our own. Not only this universe would have all opposite charges than we have, be flipped in the mirror, but anti-particles will run backward in time. Scientists predict that particles moving backward in time, must still behave in the same way and obey the same laws as they did before getting flipped. Our universe has a twin. Taken together, the two universes obey CPT symmetry.
Neutrino
First of all, let’s understand the neutrino as these forms the basis for understanding the anti-universe. We’ll learn how certain neutrinos’ discovery could provide evidence of the anti-universe theory.
An atom is made up of electrons with a negative charge — these electrons are bound around the nucleus( the center of atom) — nucleus itself is made up of protons(having a positive charge) and neutrons(with no charge). Now protons and neutrons aren’t elementary particles. They're made up of smaller particles called quarks — up quark and down quark. In addition to these, some stable ghostlike particles called electron neutrino, muon neutrino, and tau neutrinos have been discovered — they don’t interact with ordinary matter.
Neutrinos are high-energy particles that pass through most solid objects without anyone even getting noticed. Neutrinos constantly bombard Earth and studies point out that 100 trillion neutrinos pass through your body every second without posing any threat to us.
As per their nature, they rarely interact with matter. But if they do smash into an atom, they produce a shower of secondary particles that we can detect, which allows us to probe where they came from in the universe. (ANITA experiment detected these which we’ll cover later in the article.)
There are three known neutrino: the electron-neutrino, muon-neutrino and tau-neutrino (already discussed earlier). It’s well known that the three of these neutrino flavors are left-handed (referring to the direction of its spin relative to its motion). All other particles known to physics have both left- and right-handed varieties, so physicists believe there might be additional right-handed neutrinos.
Recent Discovery
In 2020, Neil Turock of the Perimeter Institute in Canada says, ‘when our big bang expansion of a matter universe happened, at the same time it created a collapsing antimatter universe containing this unwanted antimatter to be bound up in a singularity and hidden from us.’ He further says the anti-universe would stretch back in time from the Big Bang, getting bigger as it does so, and would be dominated by antimatter as well as having its spatial properties inverted compared to those in our universe
Electric fields can create particle-anti-particle pairs out of the vacuum. So his theory is built on the idea that it’s possible to drag the universe out of nothing. The implication of this model is that there would be two sides to universe — matter as well as anti-matter. He further says that considering all the concepts in Physics, the model works perfectly fine, and even this model provides the simplest explanation of the dark matter.
Explaining Dark matter
Dark matter is the most mysterious thing in the entire universe in a way how it affects ordinary matter. CPT symmetry is the only theory that explains dark matter more than any other theory. Some scientists believe the presence of fourth type of neutrino(undetected) — often termed a sterile neutrino. The electron, muon, and tau neutrinos are all left-handed. The Standard Model assumes that, unlike other particles, neutrinos don’t have such partners. But the CPT-symmetric universe disagrees, indicating they should have those partners.
Sterile neutrinos — These are also known by the name inert neutrinos. These are hypothetical particles that are believed to not interact via any other fundamental interaction of the standard model except gravity. These are the neutrinos considered right-handed. For a particle regarded as a dark matter candidate, there are certain conditions to be kept in mind — it must’ve non zero mass and no electromagnetic charge — so it makes neutrinos strong contenders.
To comply with the theory of dark matter, scientists believe there exists not just one type of sterile neutrino but three such types.
In 2018, MiniBooNE experiment, reported a stronger neutrino oscillation signal — pointing towards the possibility of finding sterile neutrinos. But it couldn’t.
ANITA Experiment
Antarctic Impulsive Transient Antenna (ANITA) experiment has been designed to study ultra-high-energy cosmic neutrinos by detecting the radio pulses emitted by their interactions with the Antarctic ice sheet. This is to be accomplished using an array of radio antennas suspended from a helium balloon flying approximately at a height of about 37,000 meters.
Usually particles and photons interact at high energies with microwave background photons — making them unable to propagate. None of the known Standard Model particles should have been able to fly all the way through the Earth and burst out the other side at such high energies, but that’s what ANITA seemed to be detecting. These findings can’t be explained by our current understanding of physics. Some physicists believe ANITA might have detected the sterile neutrinos that are directly coming from the parallel universe that runs backwards in time. While there are other scientists who don’t believe in the presence of parallel universe running backwards in time.
T2K Experiment
T2K is a neutrino experiment designed to investigate how neutrinos change from one type or flavour to another as they travel (neutrino oscillations). An intense beam of muon neutrinos is generated at the J-PARC nuclear physics site on the East coast of Japan and directed across the country to the Super-Kamiokande neutrino detector(uses water to detect neutrinos and works upon the principle of cherenkov radiation — in layman terms, produces sort of shockwaves of light similar to sonic boom and we measure the light)in the mountains of western Japan. The beam is measured — the change in the measured intensity and composition of the beam is used to provide information on the properties of neutrinos.
Scientific concepts pass through three stages before they’re accepted as reality. The first stage involves being ignored — nobody take these theories seriously. The second stage involves extreme criticism — violent stage. The third stage is the most fruitful stage as involves the theory being tagged as reality — widely accepted, and given utmost respect. The anti universe theory is probably in the first or in the second stage. It’ll take time and detection of unknown particles, the right handed neutrinos, especially the sterile neutrino to prove the theory right…….
