Antimatter has long been the subject of science fiction. In the book and film "Angels and Demons, " Professor Langdon tries to save the Vatican from an antimatter bomb. The Star Trek spacecraft Enterprise uses an annihilating antimatter engine to travel faster than the speed of light. But antimatter is also an object of our reality. Antimatter particles are almost identical to their material partners, except that they carry opposite charge and spin. When antimatter meets matter, they instantly annihilate into energy, and this is no longer fiction.
1. Antimatter should have destroyed all matter in the Universe after the Big Bang
According to the theory, the Big Bang gave birth to matter and antimatter in equal amounts. When they meet, there is mutual annihilation, annihilation, and only pure energy remains. Based on this, we should not exist.
But we do exist. And as far as physicists know, this is because for every billion pairs of matter-antimatter there was one extra particle of matter. Physicists are trying their best to explain this asymmetry.
2. Antimatter is closer to you than you think
Small amounts of antimatter constantly rain down on Earth in the form of cosmic rays, energy particles from space. These particles of antimatter reach our atmosphere at levels ranging from one to over a hundred per square meter. Scientists also have evidence that antimatter is generated during a thunderstorm.
There are other sources of antimatter that are closer to us. Bananas, for example, produce antimatter by emitting one positron - the antimatter equivalent of an electron - about once every 75 minutes. This is because bananas contain small amounts of potassium-40, a naturally occurring isotope of potassium. When potassium-40 decays, a positron is sometimes born.
Our bodies also contain potassium-40, which means that you also emit positrons. Antimatter annihilates instantly upon contact with matter, so these particles of antimatter do not last very long.
3. Humans managed to create quite a bit of antimatter
The annihilation of antimatter and matter has the potential to release tremendous amounts of energy. A gram of antimatter can produce an explosion the size of a nuclear bomb. However, humans have not produced much antimatter, so there is nothing to be afraid of.
All antiprotons created at the Tevatron particle accelerator at Fermi Laboratories will barely weigh 15 nanograms. CERN has produced only about 1 nanogram to date. At DESY in Germany - no more than 2 nanograms of positrons.
If all the antimatter created by humans annihilates instantly, its energy will not even be enough to boil a cup of tea.
The problem lies in the efficiency and cost of producing and storing antimatter. Creation of 1 gram of antimatter requires about 25 million billion kilowatt-hours of energy and costs over a million billion dollars. Unsurprisingly, antimatter is sometimes included in the list of the ten most expensive substances in our world.
4. There is such a thing as an antimatter trap
To study antimatter, you need to prevent it from annihilation with matter. Scientists have found several ways to do this.
Charged antimatter particles like positrons and antiprotons can be stored in so-called Penning traps. They are like tiny particle accelerators. Inside them, particles move in a spiral while magnetic and electric fields keep them from colliding with the walls of the trap.
However, Penning traps do not work for neutral particles like antihydrogen. Since they have no charge, these particles cannot be confined to electric fields. They are trapped in Ioffe's traps, which work by creating an area of space where the magnetic field becomes larger in all directions. Particles of antimatter get stuck in the area with the weakest magnetic field.
The Earth's magnetic field can act as traps for antimatter. Antiprotons were found in certain zones around the Earth - the Van Allen radiation belts.
5. Antimatter can fall (in the literal sense of the word)
Particles of matter and antimatter have the same mass, but differ in properties like electric charge and spin. The Standard Model predicts that gravity should act equally on matter and antimatter, but this remains to be seen for sure. Experiments like AEGIS, ALPHA and GBAR are working on this.
Observing the gravitational effect in the example of antimatter is not as easy as looking at an apple falling from a tree. These experiments require trapping antimatter or slowing it down by cooling to temperatures just above absolute zero. And since gravity is the weakest of the fundamental forces, physicists must use neutral antimatter particles in these experiments to prevent interaction with the more powerful force of electricity.
6. Antimatter is studied in particle moderators
Have you heard of particle accelerators and have you heard of particle slowers? At CERN, there is a machine called the Antiproton Decelerator, in a ring of which antiprotons are captured and slowed down to study their properties and behavior.
In ring particle accelerators like the Large Hadron Collider, particles receive an energetic boost every time they complete a circle. Retarders work in the opposite way: instead of accelerating particles, they are pushed in the opposite direction.
7. Neutrinos can be their own antiparticles
A particle of matter and its antimaterial partner carry opposite charges, which makes it easy to distinguish between them. Neutrinos, nearly massless particles that rarely interact with matter, have no charge. Scientists believe they may be Majorana particles, a hypothetical class of particles that are their own antiparticles.
Projects like the Majorana Demonstrator and EXO-200 are aimed at determining whether neutrinos are indeed Majorana particles by observing the behavior of so-called neutrinoless double beta decay.
Some radioactive nuclei decay simultaneously, emitting two electrons and two neutrinos. If neutrinos were their own antiparticles, they would annihilate after double decay, and scientists would only have to observe electrons.
The search for Majorana neutrinos may help explain why the matter-antimatter asymmetry exists. Physicists suggest that Majorana neutrinos can be either heavy or light. The lungs exist in our time, and the heavy ones existed immediately after the Big Bang. Heavy Majorana neutrinos decayed asymmetrically, which led to the appearance of a tiny amount of matter that filled our universe.
8. Antimatter is used in medicine
PET, PET (Positron Emission Topography) uses positrons to produce high-resolution body images. Positron-emitting radioactive isotopes (like the ones we found in bananas) attach to chemicals like glucose in the body. They are injected into the bloodstream, where they decay naturally, emitting positrons. These, in turn, meet with the body's electrons and annihilate. Annihilation produces gamma rays that are used to construct an image.
Scientists at CERN's ACE project are studying antimatter as a potential candidate for cancer treatment. Doctors have already figured out that they can send particle beams to tumors, emitting their energy only after they safely pass through healthy tissue. Using antiprotons will add an extra burst of energy. This technique has been shown to be effective in treating hamsters, but has not yet been tested in humans.
9. Antimatter may lurk in space
One of the ways scientists are trying to solve the problem of asymmetry of matter-antimatter is to search for antimatter left over from the Big Bang.
The Alpha Magnetic Spectrometer (AMS) is a particle detector located on the International Space Station and looks for such particles. AMS contains magnetic fields that bend the path of cosmic particles and separate matter from antimatter. Its detectors must detect and identify such particles as they pass.
Cosmic ray collisions usually produce positrons and antiprotons, but the chances of creating an antihelium atom remain extremely small due to the enormous amount of energy required for this process. This means that the observation of at least one nucleolus of antihelium will be powerful evidence of the existence of a gigantic amount of antimatter elsewhere in the universe.
10. People are actually researching how to equip spacecraft with antimatter fuel
Just a little bit of antimatter can generate massive amounts of energy, making it a popular fuel for futuristic science fiction ships.
Antimatter rocket propulsion is hypothetically possible; the main limitation is collecting enough antimatter to make this happen.
There are no technologies yet for mass production or collection of antimatter in the quantities required for such an application. However, scientists are working on imitating such movement and storage of this very antimatter. One day, if we find a way to produce large amounts of antimatter, their research could help interstellar travel come true.