The unusual substance known as antimatter may have appeared in many films about space and the future.

But it is what real scientists at the European Organization for Nuclear Research, or CERN, work on almost every day. Their research is part of efforts to find out what the universe is made of -- and how it works.

Based in Geneva, Switzerland, CERN has 23 member nations and includes scientists and other employees from many more countries.

Their research laboratory is a ring-shaped underground structure. It is 27 kilometers around and crosses the border between Switzerland and France.

In the structure lies the Large Hadron Collider. In this huge machine, the parts of atoms called protons are made to crash into one another with extreme force. This creates antimatter and other elements.

But just because physicists can make antimatter does not mean they understand everything about it. Antimatter is as old as the universe. It is part of its creation, in an event often called the "Big Bang."

Ludivine Ceard is a physicist with CERN. She discussed one of the theories behind the research.

"We have this theory that says that right after the Big Bang, there was creation in equal amount between matter and antimatter," she told VOA. "If the difference between the two is only the charge, they should have just recombined and left nothing but radiation."

Ceard added, "However, we are here...So it means at some point, matter took over the antimatter."

This, Ceard said, shows scientists that there are differences between matter and antimatter that they do not yet know.

Searching for those differences is one of the tasks for the people at the Compact Muon Solenoid, or CMS. That is one of four main experiment sites around the Large Hadron Collider at CERN.

A muon is one of the so-called elementary particles, one with no smaller parts. It is similar to an electron, but heavier. And although it is extremely small, the machine built to study it is very large.

To create muons and antimatter, groups of protons race around a circular structure in two beams, moving in opposite directions at almost the speed of light. When the physicists are ready, the beams are focused and made to hit each other in just the right place.

Rende Steerenberg leads the group in charge of seeing those crashes happen. "On either end of the experiments we will switch on focusing magnets so that the beam squeezes," he said.

This increases the chances of the beams hitting each other.

Even with 100 billion protons in a group moving in one direction and 100 billion protons moving the other way, only 50 protons are likely to connect.

Right now, however, the chance of a collision is zero. That is because the machine and the experiments around it are in the middle of a two-year work suspension for repairs and improvements. This happens every three years.

But there is still plenty of work to do.

The CMS project includes about 4,000 scientists from more than 50 countries. Patricia McBridge is a representative of the CMS project. She said the suspension does not mean scientists get free time.

"I would say that for us it's an opportunity," she said. "We're looking at ways of making the detector better, repairing things, putting in new detectors, and preparing for the future runs which ... will be running until, we hope...2035."

I'm Pete Musto.

Penny Dixon reported on this story for VOANews. Pete Musto adapted this story for Learning English. Ashley Thompson was the editor.

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antimatter – n. molecules formed by atoms consisting of antiprotons, antineutrons, and positrons

ring – n. something that is shaped like a circle

proton(s) – n. a very small particle of matter that is part of the nucleus of an atom and that has a positive electrical charge

site(s) – n. a place that is used for a particular activity

electron – n. a very small particle of matter that has a negative charge of electricity and that travels around the nucleus of an atom

beam(s) – n. a line of energy or particles that cannot be seen

focus(ed) – v. to cause something, such as attention, to be directed at something specific

squeeze(s) – v. to press together the parts and especially the opposite sides of something

opportunity – n. an amount of time or a situation in which something can be done

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