Friday, November 19, 2010

Antimatter discovery: how physicists explore science fiction frontier

Under a theory expounded in 1928 by the eccentric British physicist Paul Dirac, when energy transforms into matter, it produces a particle and its mirror image - called an anti-particle - which holds the opposite electrical charge.

When particles and anti-particles collide, they annihilate each other in a small flash of energy.

If everything were equal at the birth of the cosmos, matter and anti-matter would have existed in the same quantities.

The observable Universe would have had no chance of coming into being, as these opposing particles would have wiped each other out.

In reality, though, matter came to be far more dominant, and antimatter is rare.

But understanding why there is this huge imbalance presents a daunting technical challenge.

Until now, experiments have produced anti-atoms, namely of hydrogen, but only in a free state. That means they instantly collide with ordinary matter and get annihilated, making it impossible to measure them or study their structure.

But to science fiction fans an antimatter reactor powers the starship Enterprise in the TV series Star Trek, and in Angels & Demons a secret society hides an antimatter bomb beneath St Peter's Basilica in Rome.

Theoretically, a single pound of antimatter would contain more destructive power than the largest H-bomb.

According to Nasa scientists antimatter is not antigravity.

"Although it has not been experimentally confirmed, existing theory predicts that antimatter behaves the same to gravity as does normal matter," the space agency says.

But to produce any meaningful power it would cost a huge amount of money.

"Right now it would cost about $100 billion dollars to create one milligram of antimatter," a Nasa spokesman said.

"One milligram is way beyond what is needed for research purposes, but that amount would be needed for large scale applications.

"To be commercially viable, this price would have to drop by about a factor of Ten-Thousand."

View the original article here

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