Antimatter facts for kids

Antimatter is a special kind of material. It's made of tiny pieces called antiparticles. These antiparticles are like mirror images of the regular particles that make up everything around us. They have the same weight (mass) but the opposite electrical charge. For example, an electron has a negative charge, but its antiparticle, a positron, has a positive charge. When matter and antimatter meet, they destroy each other in a burst of energy. This process creates high-energy light (like gamma rays) and other tiny particles.

What is Antimatter?

In physics, all the basic building blocks of everything we can touch are called elementary particles. These particles often come in pairs. Each particle has what is called an antiparticle. An antiparticle looks and acts very much like its regular particle. The main difference is its electrical charge.

For example, an electron has a negative charge. Its antiparticle is called a positron, and it has a positive charge. Other antimatter particles are similar. They have the same weight and behave like regular particles. But their electrical charge is the opposite.

Think about hydrogen. A normal hydrogen atom has a negatively charged electron orbiting a positively charged proton. An antihydrogen atom is the opposite. It has a positively charged positron orbiting a negatively charged antiproton.

How Does Annihilation Work?

When matter and antimatter touch each other, they destroy each other. This process is called annihilation. It releases a huge amount of pure energy. This is why many science fiction stories use antimatter as a powerful fuel. For example, in the book "Angels and Demons," antimatter is used as a very strong weapon. Scientists are also looking into using it as a fuel source for future missions into outer space.

Einstein's Energy Formula

The famous scientist Albert Einstein discovered a formula that shows how much energy a certain amount of matter or antimatter has. This formula is . It's one of the most well-known equations in the world.

In simple terms, this formula means that if you take the mass (weight) of something and multiply it by the speed of light, and then multiply it by the speed of light again, you get the amount of pure energy it contains. The speed of light is a very big number. This means that even a tiny amount of matter can have a lot of energy. It's thought to be four times more powerful per mass than nuclear fission.

Dirac's Prediction

In 1928, a physicist named Paul Dirac was trying to find an equation. This equation would predict how very fast particles should behave. There was already an equation for slow-moving particles, but Einstein's theory of special relativity showed that fast particles could be very different. Dirac knew that particles like electrons usually move very fast. He realized the old equation wouldn't work well for them. So, he created a new equation that could describe particles moving close to the speed of light.

Dirac's new equation showed that for fast particles, the energy is not just . Instead, the energy is given by . In this equation, is called the momentum. It measures how fast a particle is going and how hard it is to stop. This equation showed that very fast particles have more energy.

When you solve this equation, you get two possible answers for energy: a positive one and a negative one. Scientists realized that the answer with negative energy could represent antimatter. This was a big step in understanding how antimatter works.

Where is All the Antimatter?

Many scientists believe that when the universe began with the Big Bang, both matter and antimatter were created. If equal amounts of matter and antimatter were made, they would have annihilated each other. After a long time, there would be no matter or antimatter left, only energy. But our universe today seems to be made almost entirely of matter, with hardly any antimatter.

Physicists don't yet know for sure if equal amounts were created. They are also wondering where the antimatter went. Was any left over from the beginning of the universe?

One idea is that there was just a tiny bit more matter than antimatter at the start. So, after most of them annihilated into energy, the leftover matter became the universe we see today. Another idea is that there's a lot of antimatter on the other side of the universe. It might be hidden far beyond what we can see. These antimatter regions could have formed their own galaxies and solar systems.

Uses of Antimatter

Because antimatter can create so much energy, it could be used for many things. For example, it could be fuel for traveling into outer space or even for our cars.

However, there's a big problem. Antimatter is extremely expensive to make. It's also very expensive to store because it can't touch regular matter. It costs hundreds of millions of dollars to make less than one-millionth of a gram of antimatter. In fact, it is the most expensive and rarest substance on Earth. Because it's so expensive, antimatter is not practical to use as a weapon or as an energy source right now.

Recently, scientists have been able to trap antimatter for over 16 minutes (1000 seconds total). This is a big step forward.

Medical Uses

Antimatter does have a use in medicine. There's a special kind of scanner called a PET scan. PET stands for positron emission tomography. This machine uses positrons (antimatter particles) that go into the human body. Doctors can watch how the positron changes into energy inside a person's body. This helps them tell if something is wrong inside.

This type of machine works differently than an X-ray machine or a magnetic resonance imaging (MRI) machine. It can help doctors see things that those other machines cannot.

Images for kids

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  A cloud chamber photograph of the first observed positron, 2 August 1932.

See also

In Spanish: Antimateria para niños