European physics laboratory CERN announced that scientists have observed for the first time how antimatter particles, the mysterious counterparts of the visible matter around us, fall downwards under the influence of gravity. The experiment was called a “tremendous breakthrough”, although most physicists awaited the result, which was predicted by Einstein’s theory of relativity in 1915.

This eliminates gravity’s ability to push antimatter upwards once and for all; It’s a discovery that will turn our basic understanding of the universe upside down. About 13.8 billion years ago, the Big Bang is thought to have produced equal amounts of matter (this is the stuff you see) and its equal but opposite counterpart, antimatter.

But there is almost no antimatter in the universe, which raises one of the greatest mysteries in physics: What happened to all the antimatter?

“Half the universe is missing,” said Geoffrey Hangst, a member of the ALPHA CERN collaboration in Geneva that conducted the new experiment. “In principle, we can build the universe – everything we know – from antimatter alone and it works exactly the same way,” he told AFP.

Physicists believe that after the Big Bang, matter and antimatter met and almost completely destroyed each other. But matter now makes up almost five percent of the universe; The rest consists of even less well-studied dark matter and dark energy, while antimatter has disappeared.

Does Newton’s apple fly?

One of the most important unresolved questions about antimatter was whether gravity causes antimatter to collapse in the same way as normal matter. Although most physicists believed this, some argued the opposite.

The famous fall of an apple inspired Isaac Newton’s work on gravity, but if that apple were made of antimatter, would it fly into the sky? And if gravity really pushes antimatter, that could mean impossibilities like a perpetual motion machine are possible.

“So why don’t you drop it a little bit and see what happens?” “Hangst,” he said.

He compared the experiment to Galileo’s famous — possibly apocryphal — demonstration in the 16th century that two balls of different masses dropped from the Leaning Tower of Pisa would fall at the same speed. But Hangst said this experiment, the result of 30 years of work on antimatter at CERN, was “a little more complex” than Galileo’s experiment.

One problem was that antimatter was virtually non-existent except as rare, short-lived particles in space. However, in 1996, CERN scientists produced the first antimatter atom (antihydrogen). Another problem was that since the electrical charges of matter and antimatter were opposite, when they met, they destroyed each other with a bright energy explosion that scientists called annihilation.

magnetic trap

To study the effects of gravity on antimatter, the ALPHA team built a 25 centimeters (10 inches) tall bottle with magnets placed on the top and bottom, placed on the tip. Late last year, scientists placed about 100 very cold antihydrogen atoms into this “magnetic trap,” called ALPHA-g.

When the strength of both magnets was reduced, anti-hydrogen particles, bouncing at 100 meters per second, managed to escape from both ends of the bottle.

The scientists then counted how much antimatter was destroyed at each end of the bottle. About 80 percent of the antihydrogen escaped from the base; This is a similar rate to how ordinary bouncing hydrogen atoms would behave if they were in a bottle. This result was published in the journal Nature It shows that gravity causes antimatter to fall downward, as predicted by Einstein’s 1915 theory of relativity.

In more than a dozen experiments, CERN scientists varied the strength of the magnets and observed the effect of gravity on antimatter at different speeds. Although the experiment rules out that gravity causes antihydrogen to rise, Hungst emphasized that it has not been proven that antimatter behaves exactly like ordinary matter.

“This is our next mission,” he said.

Physicist Marko Gersabek, who works at CERN but was not involved in the ALPHA study, said this was a “major milestone”. But this marks “only the beginning of an era” of more precise measurements of the effect of gravity on antimatter, he told AFP. Other efforts to better understand antimatter include using CERN’s Large Hadron Collider to study strange particles called beauty quarks.

And an experiment is being conducted on the International Space Station trying to trap antimatter in cosmic rays. However, physicist Harry Cliff said that for now “it remains a mystery” why the universe is full of matter but devoid of antimatter. Since the two were supposed to completely destroy each other in the early universe, “the very fact of our existence suggests that there is something going on that we don’t understand,” he added. Source