Team of scientists produces large quantity of antimatter

First time major amount has been created on Earth

September 19, 2002|By KNIGHT RIDDER/TRIBUNE

WASHINGTON - Scientists announced yesterday a major breakthrough in their long struggle to understand perhaps the weirdest stuff in the universe - antimatter, the mirror image of ordinary matter.

A team of European physicists reported the creation in a Swiss laboratory of at least 50,000 atoms of antihydrogen, the fictional fuel in Star Trek's imaginary "warp-drive."

It was the first time that a significant quantity of antiatoms, the looking-glass cousins of normal atoms, has been produced on Earth, according to a report published on the Internet by the British journal Nature.

Antimatter is composed of electrons and protons, the raw materials of atoms, but with a whopping difference - the electrical charge.

Like poles on a battery, a normal electron has a negative charge, while a proton is positively charged. In antimatter, however, the charges are reversed. The electron's antimatter counterpart, known as a positron, carries a positive charge. The antiproton has a negative charge.

When matter and antimatter collide, they annihilate each other and emit a burst of electromagnetic energy. The Reagan administration's "Star Wars" project briefly toyed with the idea of using this force to destroy incoming Soviet missiles, but U.S. officials abandoned it as unworkable.

Since the first positrons (antielectrons) were detected in 1932, thousands of physicists have been laboring to create or collect antimatter, using the world's mightiest nuclear colliders, orbiting spaceships and balloon-borne detectors.

Although antimatter sounds like science fiction, antielectrons are used every day in hospitals and clinics around the world.

They are the key to the PET (short for Positron Emission Tomography) scans employed since 1950 to observe what's going on inside a human brain.

Physicists expect that the study of antimatter will help them understand the fundamental nature of matter and what happened during the first few seconds of the universe.

An unexplained mystery has been why these opposing forms of matter didn't simply wipe each other out. By studying what happens when matter meets antimatter in the laboratory, scientists hope to resolve this puzzle.

The most likely answer seems to be that perhaps one in a billion more particles of matter were created than of antimatter, an extremely small fraction. Most of both kinds of stuff was annihilated, but enough normal matter remained to form all the galaxies, stars, planets, people, tables and chairs in the universe.

"Our entire universe seems to be residual matter," said Nigel Lockyer, a physicist at the Department of Energy's Fermilab near Chicago. "We're the leftovers. We're the scraps."

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